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Alkylmercurial encephalopathy in the monkey (Saimiri sciureus and Macaca arctoides): a histopathologic and
Abstract:
Histopathologic and autoradiographic studies were performed on monkeys of the genera Saimiri and Macaca after acute and chronic oral exposure to several dosage regimens of methylmercuric chloride (MeHg). Neuropathologic changes were primarily cortical, although subcortical lesions also were observed. Autoradiographic localization of 203-Hg was greatest within glial cells (particularly Nissl-pump astrocytes, subependymal glia and Bergmann's glia) and mast cells. High levels of label within normal appearing large neurons (particularly those within Gasserian and dorsal root ganglia) indicate a lower susceptibility of these neurons to the toxic effects of MeHg. Blood and brain levels of mercury correlated well with the degree of neuropathologic change, but individual variations in susceptibility to intoxication also existed.
Insights
This study on methylmercuric chloride (MeHg) in monkeys found that mercury primarily damages the brain cortex, concentrating in glial cells. Some large neurons showed resistance to MeHg toxicity.
Area of Science:
- Neuroscience
- Toxicology
- Pathology
Background:
- Methylmercuric chloride (MeHg) is a potent neurotoxin.
- Understanding MeHg's distribution and effects in the brain is crucial for public health.
- Primate models offer valuable insights into human neurotoxicology.
Purpose of the Study:
- To investigate the neuropathologic effects of methylmercuric chloride (MeHg) exposure in non-human primates.
- To determine the distribution of mercury in the brain using autoradiography.
- To correlate mercury levels with observed neuropathologic changes.
Main Methods:
- Histopathologic examination of brain tissue from Saimiri and Macaca monkeys.
- Autoradiographic studies using 203-Hg to trace mercury distribution.
- Acute and chronic oral exposure to various methylmercuric chloride dosages.
Main Results:
- Neuropathologic changes were predominantly observed in the cerebral cortex, with some subcortical lesions noted.
- 203-Hg accumulation was highest in glial cells (astrocytes, subependymal glia, Bergmann's glia) and mast cells.
- Large neurons in cranial and dorsal root ganglia exhibited high mercury levels but appeared morphologically normal, suggesting lower susceptibility.
Conclusions:
- Glial cells are primary targets for methylmercuric chloride neurotoxicity.
- Certain neuronal populations may possess inherent resistance to methylmercuric chloride.
- Blood and brain mercury levels correlate with neuropathologic damage, but individual susceptibility varies.