Trimethyltin-induced hippocampal degeneration as a tool to investigate neurodegenerative processes

Trimethyltin (TMT), an organotin compound with neurotoxicant effects selectively localised in the limbic system and especially marked in the hippocampus, is considered a useful tool to obtain an experimental model of neurodegeneration. Animals exposed to TMT develop behavioural alterations (hyperactivity and aggression), cognitive impairment (memory loss and learning impairment) and spontaneous seizures. TMT induces selective neuronal death involving the granular neurons of the Fascia Dentata and the pyramidal cells of the Cornu Ammonis, with a different pattern of severity and extension according to the various species studied and the dosage schedule. TMT-induced neurodegenerative events are associated with the activation of astrocytes and microglial cells and with the upregulation of proinflammatory cytokines. While the mechanisms by which TMT induces neurodegeneration are still not understood, many hypotheses seem to suggest that neuronal damage could be largely dependent on calcium overload. This review summarizes current data from in vivo and in vitro studies of the neurotoxic effects of TMT, focusing on the hypotheses regarding the mechanisms leading to neuronal death induced by the toxin.