Korean J Pathol.
1999 Sep;33(9):662-674.
Manganese Intoxication in the Rat A neuropathologic study and distribution of manganese in rat brain
- Affiliations
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- 1Department of Pathology, College of Medicine, Dongguk University, Kyungju 789-714, Korea.
- 2Department of Preventive Medicine, College of Medicine, Dongguk University, Kyungju 789-714, Korea.
Abstract
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We investigated a topographical distribution of managanese, and
immunohistochemical density of tyrosine hydroxylase (TH), and histopathologic findings
in globus pallidus and substantia nigra according to manganese dose and time course in
the brain of rats which received MnCl2 intravenously. Topographical distribution of
manganese was also investigated after injection of FeCl2. The manganese concentrations
of brain in control and experimental group were highest in pituitary gland and thalamus,
and lowest in the cerebral cortex. The manganese concentration of blood was increased
proportionally to the dose administered, and the biological half-life of blood manganese
was between 21 and 42 days. The manganese concentrations of brain were increased
proportionally to the dose, and increase rate was highest in olfactory bulb, and the
biological half-lives of brain manganese ranged from 42 days to 90 or more days; the
longest were observed in pituitary gland, medulla oblongata and cerebral cortex. In case
of administration of FeCl2, the manganese concentrations of brain were higher than that
of control group in dose of 2.5 mg/kg, and decreased proportionally to the administered
dose, resulting in lower level compared with control group in high dose of FeCl2
administered. Significantly decreased number of nerve cell and increased gliosis in
globus pallidus were observed in experimental group, which were closely correlated with
the duration after manganese injection, but no significant change of number of nerve cell
expressing TH and gliosis were observed in substantia nigra. Density of
immunohistochemical reaction for TH in globus pallidus made little difference between
control and experimental group. These results suggest that pathology of manganese
intoxication is caused by the loss of nerve cells in globus pallidus, and closely correlated
with the duration after manganese exposure.