Cryopreservation of porcine fetal ventral mesencephalic tissue for intrastriatal transplantation in Parkinson's disease

In this study we examined the efficacy of cryopreserving porcine fetal mese ncephalic tissue. After microscopical dissection of the ventral mesencephal on (VM) from E28 pig fetuses, the collection of explants was randomly divid ed into two equal parts. One part was directly prepared as cell suspension. The other part was stored in hibernation medium for less than 2 days and t hen cryopreserved as tissue fragments and stored in liquid nitrogen. After 2 weeks up to 1 year, these tissue fragments were thawed and processed as c ell suspensions. After cell counting and assessment of viability, these cel l suspensions were used to examine survival, morphology, and neurite format ion of the dopaminergic neurons in cell culture as well as after intrastria tal implantation in 6-OHDA-lesioned rats. Comparison of cryopreserved with fresh VM cell suspensions showed no significant difference with respect to cell viability and the average number of living cells per VM explant. The m orphology of cultured dopaminergic neurons after cryopreservation was ident ical to that of fresh cells. After intrastriatal implantation, survival and outgrowth of cryopreserved dopaminergic neurons as well as functional effe cts did not differ from those of fresh cells. In conclusion, the cryopreser vation technique we used proves to be a reliably effective method for stori ng porcine fetal VM tissue.