Schwann cells transplanted in the lateral ventricles prevent the functional and anatomical effects of monocular deprivation in the rat.

We investigated whether the transplant of Schwann cells prevents the physiological and morphological effects of monocular deprivation in the rat. On the day of eye opening in rats (postnatal day 14), we transplanted Schwann cells in the lateral ventricles and sutured the eyelids of one eye. After 20-30 days, at the end of the critical period for the visual system development, we analyzed the functional properties of visual cortical neurons. Spontaneous discharge, orientation selectivity, and receptive field size of visual cortical neurons in transplanted animals were in the normal range. Transplantation of Schwann cells prevented the detrimental effects of monocular deprivation on ocular dominance and binocularity of cortical neurons. Visual acuity of the deprived eye estimated by visually evoked potentials was also normal. Schwann cells derived from adult animals were as effective as those derived from neonates. The effects of Schwann cells on monocular deprivation were dependent upon the number of cells present in the transplant so that 10(6) Schwann cells were sufficient to prevent the effect of monocular deprivation, whereas 10(5) and 3.3 x 10(5) Schwann cells were ineffective, and 6.3 x 10(5) cells gave variable results. Shrinkage of the deprived lateral geniculate neurons was prevented by a transplant of 10(6) cells. In rats transplanted with hybridoma cells producing an antibody that functionally blocks nerve growth factor (NGF), we found that the effect of cotransplanted Schwann cells on monocular deprivation was partly counteracted. We conclude that transplantation of Schwann cells prevents both functional and anatomical effects of monocular deprivation, presumably acting through the production of NGF. We propose that transplants of Schwann cells could be a promising technique for clinical applications.