Systemic treatment with GM1 ganglioside improves survival and function of cryopreserved embryonic midbrain grafted to the 6-hydroxydopamine-lesioned rat striatum

Cryopreservation may allow long-term storage of embryonic ventral mesenceph alon (VM) for neural transplantation. We investigated whether the gangliosi de GM1 or the lazaroid tirilazad mesylate (U-74006F) could improve survival of grafts derived from cryopreserved VM in a rat model of Parkinson's dise ase. VM was dissected from rat embryos (E14-E15), frozen and stored in liqu id nitrogen under controlled conditions, thawed, dissociated, and then graf ted into the 6-hydroxydopamine-lesioned rat striatum. In Experiment I, VM f ragments were exposed in vitro either to GM1 (100 mu M) or to lazaroid (0.3 mu M) during all preparative steps. In Experiment II, rats receiving GM1-p retreated VM were, in addition, treated systematically with GM1 (30 mg/kg) daily for 3.5 weeks. Rats grafted with untreated cryopreserved or fresh VM were used as controls, respectively. Rats receiving fresh VM control grafts showed complete recovery from lesion-induced rotations after 6 weeks where as rats grafted with cryopreserved VM (untreated or pretreated) did not rec over. Cryografts contained significantly less (18%, control; 23%, GM1; and 12%, lazaroid) tyrosine hydroxylase-positive cells compared to fresh grafts (1415 +/- 153; mean +/- SEM). Graft volume was also significantly smaller after cryopreservation. In contrast, with additional systemic GM1 treatment cryografts contained almost the same number of tyrosine hydroxylase-positi ve cells (376 +/- 85) as fresh grafts (404 +/- 56), which was significantly more than that of untreated cryografts (147 +/- 20), showed a significantl y larger volume (0.15 mm(3)) compared to that of untreated grafts (0.08 mm( 3)) (fresh controls, 0.19 mm(3)), and induced significant and complete func tional recovery in the rotation. test. In conclusion, systemic treatment of rats with GM1 improved the low survival and functional inefficacy of graft s derived from cryopreserved VM. whereas tissue pretreatment alone with eit her GM1 or lazaroid was not effective, (C) 2000 Academic Press.