Abstracts

RATIONALE: To describe the distribution and characterize the pattern of status epilepticus (SE)-induced neuronal damage in the thalamus of developing rats. METHODS: SE was induced in 54 twelve days old rats using a LiCl-pilocarpine model. Animals were sacrificed either 48 hours or 7 days later and sections were stained with cresyl violet, Gallyas silver impregnation and immunohistochemistry for caspase-3, cytochrom c, and OX-42 (microglia) or used for Tunnel staining. RESULTS: Silver positive neurons were found in 13 thalamic regions 48 hours and in 6 regions one week after SE. No silver positivity occurred in control animals receiving the same treatment with the exception of pilocarpine. The highest density of damaged neurons was found in the mediodorsal nucleus of the thalamus bilaterally. In the same region, neurons with typical apoptotic morphology were observed in Nissl stained sections. Also, OX-42 positivity occurred in this region. In contrast, number of Tunnel positive cells was not increased in any part of the thalamus at any interval studied. CONCLUSIONS: Our data demonstrate that status epilepticus induces neuronal damage in the mediodorsal thalamus of immature rats and suggest that at least some of the susceptible neurons might undergo apoptotic cell death. Supported by a grant No.309/99/0193 of the Grant Agency of the Czech Republic.