Registration Dossier

Administrative data

Endpoint:
sub-chronic toxicity: other route
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Not conducted to GLP or guideline. Follows basic scientific principles. Dose route not applicable for human exposure.

Data source

Reference
Reference Type:
publication
Title:
Study of subacute toxicity of manganese dioxide in monkeys
Author:
Suzuki Y , Mouri T, Suzuki Y, Nishiyama N, Fujii N and Yano H
Year:
1975
Bibliographic source:
The Tohoku journal of experimental medicine, 22: 5-10

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Monkeys were exposed to MnO2 via subcutaneous injection for 9 weeks in order to investigate clinical signs of Mn poisoning, biochemical changes, manganese distribution in tissue and histopathological changes in the brain and other viscera in relation to different doses of MnO2.
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): manganese dioxide

Test animals

Species:
monkey
Strain:
other: Indian red-haired (Macca mullata)
Sex:
not specified
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 3.5 - 4.5 kg (approx.)

Administration / exposure

Route of administration:
subcutaneous
Vehicle:
physiological saline
Details on exposure:
MnO2 for injection was made up by adding pure MnO2 powder to physiological saline at concentrations to allow administration of the specified dose in 2 mL suspension.
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
9 weeks
Frequency of treatment:
Once a week
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 0.25, 0.5 and 1.0 gm MnO2.
No. of animals per sex per dose:
2 animals per dose (no data on sex)
Control animals:
yes, concurrent vehicle

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: neurological signs and symptoms, and behaviour, were observed throughout the dosing period.

BODY WEIGHT: No data

FOOD CONSUMPTION: No data

WATER CONSUMPTION: No data

OPHTHALMOSCOPIC EXAMINATION: No data

HAEMATOLOGY: Yes
- Time schedule for collection of blood: samples of blood were drawn from each animal and submitted for haematological examinations every 2 weeks
- Anaesthetic used for blood collection: No data
- Animals fasted: No data
- How many animals: All animals

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: samples taken immediately preceding sacrifice upon conclusion of the 3 month observation, or on the 86th or 93rd day
- Animals fasted: No data
- How many animals: All animals
- Parameters checked included: total protein, A/G ratio, albumin, alpha-globulin, beta-globulin, GOT, GPT, alkaline phosphatase, acid phosphatase, triglycerides, total cholesterol, phospholipid, manganese, iron, copper, calcium, magnesium

URINALYSIS: No data

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: observations were made throughout the dosing period.
- Dose groups that were examined: all groups
Sacrifice and pathology:
ORGAN WEIGHTS: Yes
Various viscera and tissues of each animal were weighed at necropsy and the organ:body weight ratio calculated.

MANGANESE CONTENT IN ORGANS: Yes
- Organs analysed: heart, lung, trachea, submandibular gland, parotid gland, stomach, small intestibne, large intestine, liver, gallbladder, apncreas, spleen, kidney, suprarene, thyroid gland, pituitary gland, ovary, lymph nodes, nerve, hair
- Brain: gray matter (cerebrum, cerebellum), white matter (cerebrum, cerebellum), basal ganglia, inter-brain, mid-bain, pons, medulla oblongata

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
not specified
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:
not examined
Behaviour (functional findings):
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
(related to Mn content in organs)
Histopathological findings: non-neoplastic:
no effects observed
Details on results:
BODY WEIGHT AND FOOD CONSUMPTION: one monkey receiving 0.25 g MnO2 weekly became unable to stay in sitting position and to take meals about the 80th day and eventually died from amciation on the 82nd day.
HAEMATOLOGY: RBC, haemoglobin and haematocrit levels declined along with differential leukocytes of decreased lymphocytes and increased neutrophils.
SERUM BIOCHEMISTRY: A decrease in albumin, increase in gamma-globin and a fall in the albumin-globin ratio were evident in treated monkeys. A slight degree of hypoferremia and of hypercupremia was also seen.
ORGAN WEIGHTS: The spleen weights were higher in the monkeys treated with 0.5 g MnO2. One monkey which died before the end of the study showed an increase in the liver kidney and adrenal weights.
MANGANESE CONTENT IN ORGANS: Dose-related increases in manganese tissue content were observed. Accumulation of Mn was prominent in glands and gall bladder.
HISTOPATHOLOGICAL FINDINGS: In monkeys receiving the highest dose an irregular arrangement of hepatic cords and lymphocytic infiltration of Gilsons capsules was seen. One monkey that died before the end of the study was seen to have microscopic evidence of pulmonary congestion and changes consistent with bronchopneumonia. No significant abnormal findings were observed in any of the remaining animals.

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Neurological effects: Symptoms developed at 3 -4 weeks after the start of the study. In particular the effects observed were: hand tremors , hyperkinetic behaviour or hyperexcitability, loss of postural equilibrium, as well as, cutaneous symptoms such as alopecia. Some of the monkeys exhibited abnormal hand movements, especially when receiving food. This symptom persisted until some monkeys became incapable of being fed without assistance. The degree of these symptoms was not dose-related but at higher dose levels the onset of symptoms was quicker.

One monkey became unable to stay in the sitting position and receive food on the 80th day and eventually died from emaciation on day 82.

Monkeys developed extrapyramidal symptoms by subcutaneous administration of manganese dioxide.

1. The degree of symptoms was not dose-related but the higher the dosage level the faster was onset of these symptoms.

2. The animal receiving manganese showed haematologically anaemic findings and a fall in serum albumin-globulin ratio

3. Manganese concentrations in various organs and tissues were closely related to the dose. The accumulation of the metal was prominent in the thyroids, parotids, gallbladder and in the nuclei of cerebral basal ganglia.

4. Histopathological examination failed to reveal any adverse change in the lungs, liver, kidney, adrenals, lymph nodes and in the central nervous system including the nuclei of basal ganglia.

Applicant's summary and conclusion

Conclusions:
Monkeys developed extrapyramidal symptoms by subcutaneous administration of manganese dioxide.
The degree of the symptoms was not dose-related but the higher the dosage level the faster was the onset of these symptoms.
The animals receiving manganese showed haematologically anemic findings and a fall in serum albumin-globulin ratio.
Manganese concentrations in various organs and tissues were closely related to the dose. The accumulation of the metal was prominent in the thyroids, paratids, gallbladder and in the nuclei of cerebral basal ganglia.
Histopathological examination failed to reveal any adverse changes in the lungs, liver, kidney, adrenals, lymph nodes and in the central nervous system including the nuclei of basal ganglia.
Close interrelation was indicated between the dynamic behaviour of manganese in the tissue and the development of neurological symptoms of manganese poisoning.
Executive summary:

Monkeys were exposed to MnO2 via subcutaneous injection for 9 weeks in order to investigate clinical signs of Mn poisoning, biochemical changes, manganese distribution in tissue and histopathological changes in the brain and other viscera in relation to different doses of MnO2.

Under the conditions of the study a close interrelation was indicated between the dynamic behaviour of manganese in the tissue and the development of neurological symptoms of manganese poisoning.