[The structural organization of suspension grafts of human embryonic midbrain in the rat brain].

Dynamics of survival, differentiation and migration of human fetal cells after their transplantation into the rat brain without immunosuppression was studied using routine histology, electron microscopy and immunocytochemistry. A cell suspension prepared from the ventral mesencephalon of human embryos 7-8 weeks of gestation was injected into the striatum of rats-recipients. The graft development depends on the intensity of immune reaction. Under a weak reaction, the viability and differentiation of human embryo cells in the rat brain were observed within the three months of the experiment. The grafted cells conserve their mediator specificity, some of them being seen to migrate into the host (rat) tissue beyond the graft. In the transplant neuropil various types of cell contacts were observed, including synapses. The described method makes its possible to study the human nervous tissue histogenesis in an abnormal environment.