Neuropathology of trimethyltin intoxication. IV. Changes in the spinal cord

Young C57BL/6N mice were injected (ip) with trimethyltin chloride at a dosage of 3.0 mg/kg body wt. Animals were sacrificed between 48 to 72 hr postinjection by means of intracardial perfusion of saline solution followed by 2.5% buffered glutaraldehyde. For light microscopy, the cords were further fixed in 10% buffered formalin and embedded in Paraplast. For electron microscopy, tissue samples were obtained from the cord levels at L1-L4, further fixed in glutaraldehyde and osmium tetroxide, and embedded in Epon. Chromatolytic and vacuolar changes involving neurons mainly in the medial and lateral motor nuclei of the anterior horns were observed. Electron microscopy revealed lysosomal accumulation and extensive dilatation of the cytoplasmic membrane systems (endoplasmic reticulum, Golgi complex). Large intraneuronal vacuoles were formed as a result of extensive intraneuronal edema. Progressive distention of the cytoplasmic membranes resulted in severe vacuolation, disintegration, and total breakdown of the neurons.