Effect of fetal striatal and astrocyte transplants into unilateral excitotoxin-lesioned striatum.

Abstract

Studies have suggested that neurotrophic mechanisms may underlie transplant-induced functional recovery. Astrocytes have been reported to be a source of neurotrophic factors. The present study examined the possible role of cultured astrocytes in promoting recovery of apomorphine-induced rotation behavior in rats with unilateral kainic acid (KA) lesions of the striatum. Five weeks after the lesions, one group of rats received fetal striatal tissue (E17) transplants, another group received transplants of cultured astrocyte suspension, and the remaining rats received sham transplants and served as controls. Apomorphine-induced rotation behavior was tested 4 weeks after the KA lesions, and 5 and 10 weeks following the transplantation. The KA-induced rotation behavior was reduced by the striatal transplants but not by the cultured astrocyte transplants 5 and 10 weeks following the transplantation. Histochemicai analysis indicated that the striatal transplants had survived and grown and contained neurons and glia with similar morphology to those in the host brain. Immunocytochemical analysis of the astrocyte transplant sites revealed heavy glial fibrillary acidic protein and OX-42 staining in the transplant areas, suggesting that the transplanted astrocytes may have survived in the host brain. Although fetal striatal transplants can ameliorate apomorphine-induced rotation behavior, transplants of astrocytes alone may not be sufficient to reverse the functional deficits produced by KA lesions.