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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:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well-documented GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

Principles of method if other than guideline:
The aim of the study was to determine if this effect is reproducible and thus the test substance may have a "protective" effect on the kidney at low concentrations.
GLP compliance:
yes (incl. QA statement)
Remarks:
testing lab.

Test material

Constituent 1
Chemical structure
Reference substance name:
Trisodium nitrilotriacetate
EC Number:
225-768-6
EC Name:
Trisodium nitrilotriacetate
Cas Number:
5064-31-3
Molecular formula:
C6H9NO6.3Na
IUPAC Name:
trisodium 2-[bis(carboxylatomethyl)amino]acetate
Details on test material:
Trilon A 92 R; purity : 95 g / 100g

Test animals

Species:
rat
Strain:
Wistar
Sex:
male
Details on test animals or test system and environmental conditions:
Male Wistar rats at an age about 12 weeks. Only animals free from clinical signs of disease were used for the study. The rats were identified clearly by ear tattoo. The rats were housed singly in type DK I I I stainless steel wire mesh cages (floor area about 800 cm2) . Underneath the cages, waste trays were fixed containing absorbent material. The animals were housed in a fully air-conditioned room. Central air-conditioning guaranteed a range of 20 - 24°C for temperature and of 30 - 70% for relative humidity . The day/night rhythm was 12 hours. Deviations from these ranges did not occur. The animal room was completely disinfected using a disinfector. The floor and the walls were cleaned once a week. The cleansing liquid used was water containing about 0.1% Incidin. The food used was ground Kliba maintenance diet mouse/rat, meal. Food and drinking water (from water bo ttles) were available ad libitum.

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
The test substance was weighed out and thoroughly mixed with a small amount of food. Then corresponding amounts of food were added to this premix in order to obtain the desired concentration , and mixing was carried out for 10 minutes in a laboratory mixer.
The mixtures were prepared weekly. The food used in the study was assayed for chemical and microbiological contaminants. The drinking water is regularly assayed for chemical contaminants.
Details on analytical verification of doses or concentrations:
No analyses of the test substance in the diet were carried out.
Duration of treatment / exposure:
4 weeks
Frequency of treatment:
daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 150 ppm
Basis:
nominal in diet
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Details on study design:
In a former study with the test substance, the 8-HO-2-deoxyguanosine content in the kidney was significantly lower at 150 ppm than in controls (BASF Project No. 99S0061 /95057).
According to previous studies with the test substance a concentration of 150 ppm in the diet was used.

Examinations

Observations and examinations performed and frequency:
The animals were examined for evident signs of toxicity or mortality twice a day (in the morning and in the late afternoon) from Mondays to Fridays and once a day (in the morning) on Saturdays, Sundays and public holidays. Additionally, further general clinical examinations were carried out daily. Food consumption was determined weekly and calculated as mean food consumption in grams per animal and day. Water consumption was determined weekly over a period of 4 days and calculated as mean food consumption in grams per animal and day. Body weight was determined before the start of the administration period in order to randomize the animals. During the administration period the body weight was determined on day 0(start of administration period) and thereafter at weekly intervals. The difference between the body weight on the respective day of weighing and the body weight on day 0 was calculated as body weight change.
Urine was collected overnight. The urine specimens were stored at about -80 °C for a possible analysis of zinc. However, on request of the sponsor, no analyses were performed.
The determination of 8-HO-deoxyguanosine was performed in the right kidney of the animals, and determination of lipid peroxidation was performed in the left kidney of the animals.
Sacrifice and pathology:
All surviving animals were sacrificed after a fasting period (withdrawal of food) for about 16 - 20 hours.
Statistics:
Means and standard deviations of each test group were calculated for several parameters.

Results and discussion

Results of examinations

Details on results:
No animal died during the study. No abnormal clinical signs were observed. No substance-related effects were obtained concerning food and water consumption. The body weight data showed no substance-related effects. No substance-related effects were seen concerning food efficiency.
Lipid peroxidation in kidneys being measured as the amount of TBA-reactive material found in tissue was identical in control and treated animals.
The level of 8-HO-dG was statistically significantly decreased by 35% in kidney DNA of treated rats when compared to controls. This was assessed as being treatment-related.

Effect levels

Dose descriptor:
NOAEL
Effect level:
9 mg/kg bw/day (nominal)
Sex:
male
Basis for effect level:
other: overall effects

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Induction of oxidative stress by Na 3NTA in kidneys was determined by measuring lipid peroxidation and 8-HO-dG. Lipid peroxidation was not affected by Na 3NTA treatment. There was, however, a statistically significant decrease in 8-HO-dG levels in kidney DNA from treated rats (35% lower than control). Although absolute levels of 8-HO-dG were rather high in this study, the effect is nevertheless considered to be biologically relevant because the data are rather consistent and were confirmed by the analysis of a second set of digested DNA-samples. These results confirm the results of a previous study (BASF Project No. 99S0061/95057) in which levels of 8-HO-dG in kidney DNA were decreased after treatment with 150 ppm Na 3NTA, too.