Emulation of seizure induced brain damage in neural tissue transplants to the anterior chamber of the eye.

We have developed a model system in which the mechanisms of neuronal damage due to hyperexcitation can be studied in isolation and where extended observation periods can be used. Substantia nigra pars reticulata (SNPR) develops a hypermetabolic necrosis following status epilepticus (Nevander et al. 1985; Auer et al. 1986). We transplanted rat fetal nigral area alone or together with fetal frontal neocortex to the anterior chamber of the eye in adult rats. Following 3 months of transplant maturation the hosts were subjected to status epilepticus for 60 min. In single nigral transplants no sign of structural damage was found. In the double transplants of frontal cortex and the substantia nigra a tissue necrosis had developed in the nigral part. This was demonstrated by a total loss of glial fibrillary acidic protein (GFA) immunoreactivity within a circumscribed necrotic region in the nigral part of the double transplant. Such a loss of GFA immunofluorescence had also developed in the host SNPR, as we have earlier shown (Eriksdotter-Nilsson et al. 1987). Thus, intraocular brain tissue transplants provide a unique model for studies on the development of neuronal damage and functional dependence between different neuronal structures for the development of such damage.