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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study
Justification for type of information:
Read across from the analogous 2 Ethylhexyl methacrylate category member donor substance.
REPORTING FORMAT FOR THE CATEGORY APPROACH
see attached category document

1. HYPOTHESIS FOR THE CATEGORY APPROACH
see attached category document, chapter 1.1

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
see attached category document, chapter 1

3. CATEGORY APPROACH JUSTIFICATION
see attached category document, chapter 5.6 (Repeated dose toxicity) and endpoint specific chapters

4. DATA MATRIX
see attached category document, endpoint specific chapters

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Test animals

Species:
rat
Strain:
Crj: CD(SD)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Japan Co. (Hino Breeding Center)
- Age at study initiation: 10 weeks old for males and females
- Weight at receipt: 351~384g for males and 212~237 for females
- Fasting period before study: no
- Housing: Stainless steel cage systems (W: 240 x D: 380 x H: 200mm) were used during quarantine and acclimatization, and 5 rats were housed in each cage. After dividing into groups, a rack of five stainless steel cages (W: 755 x D: 210 x H: 170mm) were used for individual housing. Mating was conducted in stainless steel cage systems. Also, on the 18th day of gestation, pregnant animals were moved to plastic cages (W: 310 x D: 360 x H: 175mm) in which autoclaved floors (Sunflake, Charles River Japan Co.) had been inserted to facilitate natural delivery and lactation
- Diet (ad libitum): CRF-1, Oriental Yeast Co.
- Water (ad libitum): tap water
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 44-59
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
corn oil
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:
The amount of the test substance needed at each concentration was estimated, and the substance administered was produced in the required concentration by diluting with corn oil

VEHICLE
- Justification for use and choice of vehicle (if other than water): solubility
- Concentration in vehicle: 6, 20 or 200 mg/ml
- Amount of vehicle (if gavage): 5 ml/kg
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The 6, 20 and 200 mg/ml prepared solutions were confirmed to have no problems with stability for 7 days under cool and dark conditions after preparation, and for four hours under dark conditions at room temperature.
The concentration of the test substance in the administration substance at each concentration used on the administration starting date and the administration ending date for males was measured by HPLC. The results of the test substance concentration were 99.5~110% of the displayed concentration, and as they were within the range of acceptable concentration (within ±10% of the displayed concentration).
Duration of treatment / exposure:
Males: 14 days before mating and 35 days after, for a total of 49 days
Females: 14 days before mating and a total of 41~47 days during mating, gestation and day 4 of lactation to the day before necropsy
Frequency of treatment:
Once daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0 (vehicle), 30, 100, 300, 1000 mg/kg/day
Basis:
actual ingested
No. of animals per sex per dose:
12
Control animals:
yes, concurrent vehicle
Details on study design:
Post-exposure period: 1 day
- Dose selection rationale:
The dose was determined by the results of the preliminary testing (administration doses: 0, 125, 250, 500 and 1000 mg/kg, 5 in each group) with oral administration using male rats for a period of two weeks. Salivation was noted immediately after administration in the groups greater than 125 mg/kg, and low body weight values were noted in the 1000 mg/kg group but there were no confirmed fatalities in any of the groups. Therefore, the dose for this study was set with a maximum dose of 1000 mg/kg in conjunction with the dose limits found in the OECD guidelines, and included ratio of approximately 3, with doses of 300, 100 and 30 mg/kg. Furthermore, a group administered the same quantities of a medium (corn oil) as the test substance was considered the control group.
- Rationale for animal assignment (if not random):
To divide into groups, the computer was used to separate by weights and then random sampling was performed to make each group uniform in terms of average weight and distribution for the administration starting date. Animals remaining after allocation into groups were euthanized under ether anesthesia on the administration starting date and discarded
Positive control:
not require

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily
- Cage side observations checked in table [No.?] were included.

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations:
Males: twice weekly (Days 1, 4, 8, 11, 15, 18, 22, 25, 29, 32, 36, 39, 43, 46 of administration and the necropsy day)
Female: 14 days before mating started and two times each week during mating season (Measurement days: Days 1, 4, 8, 11, 15 and 18 of administration), and measured on day 0, 7, 14 and 21 during gestation, and day 0 and 4 during lactation.

FOOD CONSUMPTION : Yes
Males: twice weekly (Days 3, 6, 10, 13, 24, 27, 31, 34, 38, 41, 45 and 48 of administration)
Female: twice weekly (14 days before mating, on day 2, 9, 16 and 21 during gestation as well as on day 4 of lactation)
FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes (male only)
- Time schedule for collection of blood: D49
- Anaesthetic used for blood collection: Yes (sodium pentobarbital)
- Animals fasted: Yes
- How many animals: 12
- Parameters checked in table [No.2] were examined.

CLINICAL CHEMISTRY: Yes (male only)
- Time schedule for collection of blood: D49
- Animals fasted: Yes
- How many animals: 12
- Parameters checked in table [No.3] were examined.

URINALYSIS: Yes (male only)
- Time schedule for collection of urine:
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters checked in table [No.1] were examined.

NEUROBEHAVIOURAL EXAMINATION: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes

ORGAN WEIGHTS: Yes
Brain (cerebrum, cerebellum and medulla oblongata), pituitary gland, thyroid gland, thymus, heart, liver, spleen, kidney, adrenal gland, ovaries, testes and epididymides. The pituitary and thyroid glands were measured after fixing in 20% neutral buffered formalin for one night

HISTOPATHOLOGY: Yes
H-E stained tissue specimens were produced from the heart, lungs, airway, liver, pancreas, stomach, duodenum, jejune, ileum, appendix, colon, rectum, thymus, spleen, lymph nodes (submandibullar, mesenteric), kidney, adrenals, bladder, ovaries, uterus, vagina, testes, epididymides, seminal vesicle, prostate, pituitary gland, thyroid gland, glandura parathyroid (only on animals that could be examined), brain (cerebrum, cerebellum and medulla oblongata) spinal cord, sciatic nerve, and bone marrow (sternum, femur) in the control group and the maximum dose (1000 mg/kg) group, and histopathological examinations performed. During the examinations for the 1000 mg/kg male group, the livers and spleens were found to show a difference in the number of animals exhibiting abnormalities compared to the control group, so the 30, 100 and 300 mg/kg groups were examined in the same manner. During the necropsy for one case (No. 308) in the 300 mg/kg group, an abnormality was confirmed so the epididymides were also examined. During the examinations for the 1000 mg/kg female group, the thymus, spleens and brains were found to show a difference in the number of animals exhibiting abnormalities compared to the control group, so the 30, 100 and 300 mg/kg groups were examined in the same manner
Statistics:
The mean values and standard deviations were calculated for each group for body weight, food consumption, absolute and relative weights of organs, urine volume, urine specific gravity, hematological examination results and blood chemistry examination results.
Equal distribution examination was conducted using the Bartlett method, and if there was equal distribution, a distribution analysis was performed using analysis of variance, and if significant, the Dunnett method was performed. On the other hand, if equal distribution was not confirmed, analysis of variance was conducted using a ranking (Kruskal-Wallis test), and if significant, the ranking was used and a Dunnett type of examination method was performed.
In the histopathological examination, in addition to the suggestion that there was a toxicological impact in the group with the maximum dose, the findings on the organs and tissues from the other groups that were subject to examination were conducted by using the Dunnett method with the ranking given above to compare the groups with the control group. If a significant difference with the control group was confirmed, the dose response was studied using the Cochran Armitage test for trend.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
effects observed, treatment-related
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
not examined
Details on results:
Clinical signs:
MALES:  There were no confirmed deaths or near-deaths in any of the groups.
In the observations on the overall condition, nothing abnormal was noted in any of the animals in the control group during the observation period. In the 30 mg/kg group, there were 1~3 cases where salivation was noted on day 9, 10, 12, 13 and 24 of administration. In the 100 mg/kg group, there were 1~3 cases where salivation was noted on day 5, 9, 10, 12~18, 23~28, 30, 33 and 43 of administration. In the 300 mg/kg group, there were 1~4 cases where salivation was noted on day 4~28, 33, 35, 39, 44~46, 48 and 49 of administration. In the 1000 mg/kg group, there was 1 case of soiled fur on days 16~23 of administration, and there were 4~all cases where salivation was noted on days 2~49 of administration. Salivation was seen for approximately 3~30 minutes after administration in all groups, and no changes were seen in the length of time that salivation continued, even during administration.
FEMALES: Neither dead nor moribund animal was observed in the control group and  the 30, 100 and 300 mg/kg group. In the 1000 mg/kg group, one animal died on Day 15 of administration. In the dead animal, salivation and abnormal gait were observed from Days 2 and 8 of administration to the day before death, respectively. In clinical observation in the surviving animals, there was no abnormality in any animal in the control group throughout the  observation period. In the 30 mg/kg group, there were 1~2 cases where salivation was noted on day 10, 12~14 of administration. In the 100 mg/kg group, there was 1 case where salivation was noted on day 12 and 13 of gestation. In the 300 mg/kg group, there were 1~3 cases where salivation was noted on day 10, 12~15 and 17 of administration, day 0, 3, 4, 9, 12~14 and 17 of gestation. In the 1000 mg/kg group, there was 1 case of soiled fur on days 16~19 of administration and day 0~3 of gestation, and there were 1~11 cases where salivation was noted on days 2, 4~19 of administration, 0~23 days of gestation, and day 0 and 1 of lactation. Salivation was seen for a period of approximately 3~30 minutes after administration in all groups.

Body weight:
MALES: The body weight of animals in the 30, 100 and 300 mg/kg groups showed almost similar changes to those in the control group, and  no significant difference was observed on any determination day. In the  1000 mg/kg group, significantly low  body weights were observed from Day  18 to Day 50 of administration compared with the control group.
FEMALES: The body weight of animals in the 30, 100 and 300 mg/kg groups showed almost similar changes to those in the control group before  mating, and no significant difference was observed on any day of  determination. In the 1000 mg/kg group, significantly low body weights were observed from Day 4 to Day 15  of administration compared with the control group. In the dead animal in the 1000 mg/kg group, decreased body weight was observed before death.   During the gestation period, the body weights in the 30, 100 and 300  mg/kg groups showed almost similar changes to the control group, and no  significant difference was observed on any determination day. In the 1000  mg/kg group, significantly low body weights were observed on Days 14 and 21 of gestation compared with the control group.   During the lactation period, the body weights in the 30, 100 and 300  mg/kg groups showed almost similar changes to the control group, and no  significant difference was observed on any day of determination. In the  1000 mg/kg group, significantly low body weight was observed on Days 0  and 4 of lactation compared with the control group.

Food consumption:
MALES: Food consumption in the 30 mg /kg group was almost similar to as that in the control group, and no significant difference was observed on any determination day. In the 100 mg /kg group, significantly high food consumption was observed compared with the control group on Day 3 of administration, but it was not a dose-dependent change.  Food consumption in the 300 mg /kg group was almost similar to that in the control group, and no significant difference was observed on any day of determination. In the 1000 mg/kg group, significantly low food consumption was observed on Days 6, 10, 31 and 34 of administration compared with the control group.
FEMALES: Food consumption in the 30, 100 and 300 mg/kg groups showed almost the same changes as that in the control group before mating, and no significant difference was observed on any determination day. In the 1000 mg/kg group, significantly low food consumption was observed compared with the control group on Days 3 and 6 of administration. In the dead animals in the 1000 mg/kg group, a marked decrease in food consumption was observed before death. During the gestation period, food consumption in each group showed almost the same change as that in the control group, and no significant difference was observed on any day of determination. During the lactation period, food consumption in the 30, 100 and 300  mg/kg groups showed no significant difference compared with the control group. In the 1000 mg/kg group, no significant difference was observed compared with the control group, but food consumption tended to be low on Day 4 of lactation.

Hematology (Table 2):
MALES ONLY: In the 30, 100 and 300 mg/kg groups, no significant differences in any parameter. In the 1000 mg/kg group, significantly low  values of erythrocyte cell count, hemoglobin, hematocrit and white blood cell count were observed compared with the control group.  

Blood biochemistry (Table 3):
MALES ONLY:  In the 30, 100 and 300 mg/kg groups, no significant difference was observed in any parameter compared with the control group. In the 1000 mg/kg group, significantly high values of albumin, A/G ratio, urea nitrogen and Cl and significantly low values of total protein, alpha3-globulin and beta-globulin were observed compared with the control group. In the 1000 mg/kg group, additionally, two animals showed high GOT and GPT.Though group data were not significantly different from the control group statistically, GOT and GPT  mean values were high.

Urinalysis (Table 1):
MALES: In the 30, 100 and 300 mg/kg groups, there were no significant differences in the urine volume and the specific gravity  compared with the control group. In the 1000 mg/kg group, significantly  high specific gravity was observed compared with the control group.   The color, pH, protein, glucose, ketone bodies, bilirubin, occult blood, urobilinogen and urinary sediments were nearly identical to the control group in each administration group.

Necropsy findings:
MALES:There was no abnormality in the control group and the 30 and 100 mg/kg  groups. In the 300 mg /kg group, yellowish white nodules were observed in the tail of the right epididymis in one animal. In the 1000 mg/kg group,  atrophied right testis and atrophy in right epididymis were observed in  one animal. However, these changes were observed in few animals and  judged to be incidental.
FEMALES: In the necropsy of surviving animals, there was no abnormality in the control group and the 30, 100 and 300 mg/kg groups. In the 1000 mg/kg group, an atrophied thymus was observed in one animal. In the necropsy of dead animals in the 1000 mg/kg group, atrophy in thymus and hypertrophy of bilateral adrenal glands were observed.

Organ Weight:
MALES (Table 4): In the 30 and 100 mg/kg groups, there were no significant differences in any of the absolute and relative organ weights compared with the control group. In the 300 and 1000 mg/kg groups, a significantly high absolute kidney weight and significantly high values of relative weights of the pituitary gland, liver and kidneys were observed compared with the control group. Additionally, in the 1000 mg/kg group, a significant high relative brain weight was observed compared with the control group, but since such a tendency was not observed in the absolute weight, it was judged as the finding unattributable to administration.
FEMALES (Table 6): In the 30 mg/kg group, there were no significant differences in any of  the absolute and relative organ weights compared with the control group.  In the 100 mg/kg group, there was a significantly high relative kidney  weight compared with the control group. In the 300 mg/kg group, there was  a significantly high relative kidney weight compared with the control  group. In addition, significantly low absolute and relative liver weights  were observed in the 300 mg/kg group compared with that in the control  group. They were, however, not the dose-dependent changes and judged not  attributable to administration. In the 1000 mg/kg group, there were a  significantly high absolute kidney weight and significantly high relative  weights of thyroid gland, liver and kidney compared with the control  group. In addition, significantly low absolute weights of pituitary gland  and heart and a significantly high relative brain weight were observed in  the 1000 mg/kg group compared with the control group. However, since  these changes showed no certain tendency in both absolute and relative  weights, they were judged not to be attributable to administration.

Histopathology:
MALES (Table 5):Focal necrosis of the liver was observed in two animals in the 1000 mg/kg group, but the severity was very mild.  Decreased extramedullary hematopoiesis in the spleen was observed in three animals in the 1000 mg/kg group, but the severity was mild. The decreased extramedullary hematopoiesis in the spleen in the 1000 mg/kg group was significantly different from that in the control group.  Hyaline degeneration of the proximal tubule of the kidney, hemiatrophy of the seminiferous tubule of the testis, unilateral spermatic granuloma of the epididymis, decreased sperms and intraluminal cell debris were observed. Since they were the changes sometimes observed in the control group and observed in one animals, they were judged as incidental changes. There were no abnormalities in the heart, lungs, trachea, pancreas, stomach, duodenum, jejunum, ileum, cecum, colon, rectum, thymus, lymph nodes (mandibular and mesenteric), adrenal glands, urinary bladder, prostate gland, seminal vesicles, pituitary gland, thyroid gland, parathyroid gland, brain  (cerebrum, cerebellum, medulla oblongata), spinal cord, sciatic nerve and  bone marrow (sternal and femoral) in the control group and the 1000 mg/kg  group.
FEMALES (Table 7): In surviving animals, atrophy in cortex of the thymus was observed in 2 animals in the control group and 3 animals in the 1000 mg/kg group. Its severity was very mild to mild in the control group and very mild in the 1000 mg/kg group. In addition, atrophy in medulla of the thymus was observed in one animal in the 1000 mg/kg group, but the severity was mild. The number of animals showing atrophied cortex or medulla was slightly larger in the 1000 mg/kg group compared with the  control group. In the spleen, decreased extramedullary hematopoiesis was observed in 4 animals in the 1000 mg/kg group, but the severity was mild. In brain, softened lesion of the medulla oblongata was observed in 2 animals in the 1000 mg/kg group, but the severity was very mild to mild. The decreased extramedullary hematopoiesis in the spleen and softened lesion of the medulla oblongata in the brain showed significant differences in the 1000 mg/kg group compared with the control group. Further, moderate unilateral extensive inflammation of the lung was observed in one animal in the 1000 mg/kg group, but it was judged as an accidental change. There were no abnormalities in the heart, trachea, liver, pancreas, stomach, duodenum, jejunum, ileum,  cecum, colon, rectum, lymph nodes (mandibular and mesenteric), kidneys,  adrenal glands, urinary bladder, ovaries, uterus, vagina, pituitary  gland, thyroid gland, parathyroid gland, spinal cord, sciatic nerve, bone  marrow (sternal and femoral) and mammary gland in the control group and  the 1000 mg/kg group. In one dead animal in the 1000 mg/kg group, a mild decrease in zymogen granules in the acinar cells of the pancreas, moderate atrophy of the cortex and medulla of the thymus, a moderate decrease in extramedullary hematopoiesis and moderate atrophy of the white pulp of the spleen, moderately softened  lesion of the medulla oblongata of the brain and a moderate decrease in  hematopoiesis in the bone marrow were observed. There was no change  suggesting hypertrophy of the bilateral adrenal glands observed at  autopsy.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
100 mg/kg bw/day (nominal)
Sex:
male
Basis for effect level:
other: high absolute and relative kidney weights
Dose descriptor:
NOAEL
Effect level:
30 mg/kg bw/day (nominal)
Sex:
female
Basis for effect level:
other: high relative kidney weight at doses of 100 mg/kg or more; see also the RSA review of this study

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Table 1: Urinary examination of male rats (P)

Group

Control

2-ethylhexyl methacrylate

(mg/kg)

0

30

100

300

1000

Number of males

12

12

12

12

12

Volume (ml): Mean ± S.D.

13.27±5.66

11.53±4.05

11.94±4.92

14.08±3.79

12.58±3.59

Specific gravity: Mean± S.D.

1.0523 ±0.0174

1.0560±0.0131

1.0588±0.0177

1.0514±0.0156.

1.0700±0.0134*

Color

Light yellow

12

12

12

12

12

pH

5.5

0

0

1

0

0

6.0

0

1

2

2

1

6.5

0

1

1

2

3

7.0

3

3

0

2

3

7.5

2

2

2

3

2

8.0

3

3

4

1

3

8.5

2

1

2

2

0

4.0

2

1

0

0

0

Protein

Negative

2

0

1

1

0

Trace

2

0

1

0

1

30 mg/dl

2

7

5

5

6

100 mg/dl

6

4

4

4

5

>300 mg/dl

0

1

1

2

0

Glucose

Negative

12

12

12

12

12

Ketone body

Negative

0

0

1

0

1

5 mg/dl

3

3

0

2

2

15 mg/dl

6

8

11

7

9

40 mg/dl

3

1

0

3

0

Bilirubin

Negative

11

12

12

12

11

Slight

1

0

0

0

1

Occult blood

Negative

12

10

12

12

12

Trace

0

1

0

0

0

Slight

0

1

0

0

0

Urobilinogen

0.1     E.U./dl

7

6

6

8

8

1.0     E.U./dL

5

6

6

4

4

Urinary sediments

Epithelialcells

0-20cells/100 fields

11

11

11

11

10

21-100 cells/100 fields

1

1

1

1

2

Erythrocytes

0-20 cells/100 fields

12

11

12

12

12

21-100 cells/100 fields

0

1

0

0

0

Leukocytes

0-20cells/100 fields

12

12

12

12

12

Casts

Not observed

12

12

12

12

12

Crystals

Not observed

3

4

4

5

4

Observed

9

8

8

7

8

Significantly different from control (*: P<0.05).

Table 2: Hematotogical examination of male rats (P)

Group

Control

2-ethylhexyl methacrytate

(mg/kg)

0

30

100

300

1000

Number of males

12

12

12

12

12

RBC (104/mm3)

851.8±50.2

854.1±41.6

854.3±47.6

815.7±33.6

770.5±63.0**

Hemoglobin (g/dl)

15.61±0.66

15.62±0.54

15.61±0.64

15.05±0.57

14.48±0.96**

Hematocrit (% )

46.47±2.39

46.57±1.92

46.55±2.11

44.83±2.01

42.60±3.43**

MCV (µm3)

54.58±1.10

54.55±1.32

54.52±1.24

54.96±1.46

55.29±0.98

MCH(pg)

18.34±0.46

18.31±0.52

18.29±0.59

18.45±0.56

18.82±0.57

MCHC(g/dl)

33,61±0.56

33.57±0.62

33.54±0.42

33.60±0.52

34.03±0.62

Platetet (104/ mm3)

102.78±13.28

109.15±13.35

105.60±12.17

102.51±12.31

99.59±8.19

RET (o/oo)

22.4±4.0

22.4±4.1

20.8±3.1

25.3±4.3

23.8±5.8

PT(Sec.)

15.69±1.08

17.04±1.55

17.46±4.58

17.68±3.70

15.98±1.74

APTT (Sec. )

32.79±2.41

35.13±2.26

33.01±4.07

35.28±3.64

32.78±3.26

Fibrinogen(mg/dl)

243.3±20.1

247.1±13.3

243.8±21.8

242.4±13.0

228.9±13.0

WBC (102/mm3)

80.0±26.4

66.3±23.4

73.8±22.5

59.5±9.4

49.3±12.2**

Differential leukocyte (%)

Lymphocyte

88.3±7.7

90.5±3.3

87.6 ±5.1

90.6±2.5

87.1±6.3

Neutrophile

10.7±7.4

8.5±3.1

10.9±4.3

8.4±2.3

11.6±6.2

Eosinophile

0.6±0.8

0.7±0.9

1.2±1.2

0.4±0.7

0.8±0.9

Basophile

0.0±0.0

0.0±0.0

0.0±0.0

0.0±0.0

0.0±0.0

Monocyte

0.5±0.7

0.3±0.7

0.3±0.9

0.6±0.7

0.6±0.5

Each value shows mean ±SD

Significantly different from control (**: P<0.01).

Table 3: Blood chemical examination of male rats (P)

Group

Control

2-ethylhexyl methacrylate

(mg/kg)

0

30

100

300

1000

Numberof males

12

12

12

12

12

GOT(IU/l)

62.68±9.07

61.67±13.56

60.85±9.22

55.79±7.36

100.85±111.48

 

GPT(IU/l)

20.25±4.27

17.53±2.95

18.41±3.57

16.01±3.07

48.63±78.98

ALP(IU/l)

83.50±18.08

95.17±20.41

84.35±11.11

84.47±28.62

95.91±19.38

LDH(IU/l)

225.71±73.25

232.08±79.76

242.41±82.47

207.47±55.64

240.89±188.46

γ-GTP(IU/l)

1.39±0. 50

1.48±0.55

1.67±0.58

1.48±0.55

2.04±0.93

TP (g/dl)

5.45±0.27

5.43±0.21

5.40±0.19

5.30±0.13

5.12±0.26**

Albumin (g/dl)

2.888±0.127

2.892±0.106

2.848±0.105

2.842±0.083

2.918±0.126

Protein fraction (%)

Albumin

53.02±1.89

53.26±2.15

52.76±1.55

53.63±1.54

57.08±1.88**

Α1-glo

21.94±2.14

22.27±1.75

22.24±1.72

22.17±2.40

20.38±1.66

α2-glo

5.17±0.63

5.36±0.77

5.36±0.80

5.23±0.76

4.98±0.58

Α3-glo

5.58±0.48

5.56±0.39

5.41±0.39

5.43±0.40

4.63±0.42**

β-glo

11.27±0.61

10.88±1.02

11.45±0.85

10.70±0.61

10.19±0.85**

γ-glo

3.03±0.69

2.68±0.58

2.78±0.54

2.85±0.48

2.75±0.68

A/Gratio

1.132±0.086

1.144±0.097

1.118±0.067

1.159±0.074

1.333±0.101**

T-BIL(mg/dl)

0.058±0.011

0.059±0.008

0.060±0.007

0.056±0.007

0.061±0.016

BUN(mg/dl)

16.08±1.39

15.33±2.05

15.19±2.24

17.03±1.99

18.32±2.71*

Creatinine(mg/dl)

0.510±0.030

0.504±0.028

0.494±0.036

0.486±0.036

0.511±0.072

Glucose(mg/dl)

116.31±11.84

121.81±15.61

121.32±10.40

120.83±1.0.73

121.72±8.87

T-CH0(mg/dl)

51.86±9.88

53.78±13.83

54.98±9.42

55.92±8.69

54.73±9.94

TG(mg/dl)

45.47±11.05

42.60±17.13

56.28±20.95

38.62±13.82

36.28±12.59

Na (mEq/l)

148.17±1.77

148.31±1.18

147.67±1.56

148.68±1.35

147.78±1.88

K (mEq/l)

4.660±0.287

4.609±0.304

4.597±0.215

4.618±0.279

4.671±0.284

Cl (mEq/l)

105.72±1.35

105.69±1.28

106.33±0.91

106.32±1.22

107.82±1.36**

Ca(mg/dl)

10.15±0.25

10.03±0.31

10.08±0.30

10.02±0.33

9.83±0.32

IP(mg/dl)

7.18±0.68

7.32±0.61

7.56±0.70

7.41±0.56

7.48±0.61

Eachvalue showsmean ± S.D.

Significantlydifferentfromcontrol(*:P<0.05,**:P<0.01).


Applicant's summary and conclusion

Conclusions:
NOAEL of this chemical is considered as 100 mg/kg/day for males since high absolute and relative kidney weights were observed after administration at a dose of 300 mg/kg, and 30 mg/kg/day for females since a high relative kidney weight was observed after administration at a dose of 100 mg/kg.
Executive summary:

In an OECD Guideline 422 and GLP study, 2 -ethylhexyl methacrylate in corn oil was administered by gavage to 10 male and 10 female rats at dose levels of 0, 30, 100, 300, or 1000 mg/kg/day. The NOAEL for EHMA was 100 mg/kg/day in male rats and 30 mg/kg/day in females. One high-dose (1000 mg/kg/day) female died during the study. Treatment-related decreases in body weight and food consumption occurred in high dose animals only. Salivation was observed after administration in both male and female animals at doses of 30 mg/kg/day or higher appeared not to be treatment related. Male rats in the 300 and 1000 mg/kg/day groups had significantly high absolute and relative kidney weight and increased relative weights of the pituitary gland, and liver. The 300 mg/kg/day level was considered a LOAEL for males based on organ weight changes despite lacking histopathology because of corresponding changes at the high dose (1000 mg/kg/day) in serum BUN (kidney); protein, enzymes and A/G ratio (liver), and hematology (spleen and pituitary). In high dose females, there were significantly high absolute kidney weights and increased relative weights of thyroid gland, liver and brain. There was increased relative (but not absolute) kidney weights in females at both 100 and 300 mg/kg, however the effect at 100 mg/kg value was considered biologically insignificant based on the magnitude of the change compared to controls. The LOAEL for females is considered to be 300 mg/kg/day based on organ weight changes in both liver (absolute and relative) and kidney (relative only). Blood samples were not taken from the pregnant females, unlike males. Gross findings included yellowish white nodules in the tail of the right epididymis in one male animal at 300 mg/kg/day and atrophied thymus in one female of the 1000 mg/kg/day dose group. Treatment-related microscopic changes were observed in the liver and spleen of high dose males and in the thymus, spleen and brain of high dose females. These changes consisted of mild focal necrosis of the liver in two male rats, mild decreased extramedullary hematopoiesis in the spleen of three male rats and four female rats, mild atrophy of the thymus in four female rats, and a softened lesion of the medulla oblongata in two female rats at 1000 mg/kg/day.