[An embryonic tissue xenograft of neocortex in old rats].

To 31 2-3-year-old white noninbred rats transplantation of the neocortical tissue, obtained from human embryos 12-20-week-old has been performed. Under aseptic conditions after an osseous-plasty cranial trepanation (thiopental narcosis intraperitoneally) tissue pieces 2 x 3 mm have been put into an artificially made cavity in the cortex of the right parietal region. In 3-4 weeks after the operation, reparation takes place at the intracellular level both in neurons and in microglial elements, both hemispheres being involved in the process of compensatory-restoration process equivalently: realization of regeneration is performed in the brain as a single organ. The working hypertrophy of the neurons results from increase of both the perikaryon and the previously shrunken nucleus against the background of their normochromia and distinct structurally. Therefore, massive diffusive dystrophy of nervous cells disappears. Amount of microglial elements increases essentially. A close contact of neurons with satellite cells demonstrates certain activation of a single metabolic system neuron-neuroglia. Thus, xenotransplantation of the embryonal tissue of the neocortex to old animals produces a positive reparative process in involutively altered neurons and in macroglial elements.