The properties of cultured fetal human and rat brain tissue and its use as grafts for the relief of the parkinsonian syndrome.

Primary cultures were derived from human fetal ventral mesencephalon and cerebral cortex at 7-11 weeks gestation, and from fetal rat mesencephalon and cortex at embryonic day 14-15. Immunohistochemical analysis of the mesencephalic cultures using antibodies to tyrosine hydroxylase (TH) showed between 0.1-0.5% of human cells to be TH positive and 0.1-1% of rat cells to be TH positive. HPLC analysis of extracts from the cultures showed that they had the ability to synthesise and store dopamine. Implantation of the cultured human and rat mesencephalic tissue into a 6-hydroxydopamine rat model of Parkinson's disease produced marked recovery from amphetamine induced rotational asymmetry in the recipient rats, but no such recovery was observed following implantation of cortical cultures. Histological examination demonstrated the presence of surviving human mesencephalic and cortical grafts at least 6 months after implantation. Implants of cultured fetal rat tissue were less obviously but still significantly effective in these experiments. These rat tissue grafts were detectable for periods of at least 6-8 weeks by histological staining.