Neuropathology of trimethyltin intoxication. II. Electron microscopic study on the hippocampus

When mice ( BALB c) were given a single injection of trimethyltin chloride (TMT) at a dosage of 3.0 mg TMT/kg body wt, extensive lesions were observed in the hippocampus at 48 hr after TMT administration. Electron microscopy revealed extensive neuronal necrosis among the granule cells and many of these necrotic neurons also displayed the phenomenon of karyorrhexis (fragmentation of the pyknotic nuclei). Although few necrotic cells were found among the pyramidal neurons, extensive accumulation of lysosomes was found within the neuronal bodies and processes of these nerve cells. Intracellular edema was a prominent finding in both cell types of the hippocampus. Such phenomenon was represented by severe distention of the cytoplasmic membrane systems (endoplasmic reticulum and Golgi complex) within the pyramidal cells and extensive swelling of the cytoplasm and neuronal processes of the granule neurons. Vacuolation of both cell types occurred as a result of these edematous conditions. It is postulated that TMT induced a severe disruption of oxidative phosphorylation and ATP production in these neurons leading to rapid cell death and/or cellular edema of these nerve cells.