Embryonic nervous tissue transplantation accelerates restoration of hypoxia-damaged blood-brain barrier in rats.

The aim of this work was to study the effect of hypoxia on blood-brain barrier (BBB) permeability to blood globulins in adult Wistar rats; the influence of hypoxia combined with embryonic nervous tissue (ENT) transplantation; as well as that of hypoxia and brain injury without transplantation. Impairments in BBB were detected by a change in the brain vessels permeability to blood globulins on the basis of Coons's reaction. BBB permeability was checked at different time intervals: from one to thirty five days after the hypoxia seance, hypoxia and brain injury, and hypoxia with ENT transplantation. BBB permeability to blood globulins was found to be significantly increased after the exposure to hypoxia, reaching its maximum by the 7th day and returning to normal only by the 30th day after the hypoxia seance. Similar results were obtained in the case of brain injury following an exposure to hypoxia. Although there was an insignificant decrease in BBB permeability seen one day after the rats were subjected to brain injury, the duration of BBB restoration was the same as in hypoxia-exposed rats (30 days). In the case of ENT transplantation into the brain of adult hypoxia-exposed rats the restoration of the damaged BBB proceeded considerably faster than in hypoxia-exposed rats with brain injury. By the end of the first week after the transplantation the functions of BBB were completely normalized and in some cases the barrier was already restored.