Effects of trimethyltin on the mouse hippocampus and adrenal cortex

The effects of trimethyltin (TMT) on the mouse adrenal histology and its relationship with neuropathology occurrence was studied. Young, male CD-1 mice were divided into three groups: group I, injected on 3 consecutive days with 1.0 mg TMT/kg body weight (b.w.); group II, injected on 2 consecutive days with 1.5 mg TMT/kg b.w.; and group III, injected with a single acute dose of 3.0 mg TMT/kg b.w. Control animals were injected with saline solution. The brain and adrenal glands were sampled for light-microscopic examination. Although all animals received the same total amount of TMT, pathological changes in the granule cells of the fascia dentate appeared to be group III greater than group II greater than group I, suggesting that acute exposures produced a more severe damage to the fascia dentate neurons. Likewise, the adrenal weights of the animals were group III greater than group II greater than group I greater than or equal to control. Significant proliferation and enlargement of the eosinophilic or the "X zone" were observed in the TMT-treated, particularly groups II and III, animals. The expansion of the eosinophilic cell layer (X zone) was accomplished at the expense of the cortical fasciculata cells. Transformation of fasciculata cells into eosinophilic cells could also be demonstrated. As the eosinophilic cells are known to be active in corticosterone production as seen in stress situations, the proliferation of these cells may reflect a feedback response to the hippocampal hyperexcitation.