A COMPARATIVE-STUDY OF PREPARATION TECHNIQUES FOR IMPROVING THE VIABILITY OF NIGRAL GRAFTS USING VITAL STAINS, IN-VITRO CULTURES, AND IN-VIVO GRAFTS

The intracerebral transplantation of embryonic dopaminergic nigral neu rons, although relatively successful, leads to a fairly low yield of s urviving cells. Many factors may influence the viability of dopaminerg ic grafts and one of these is the preparation of the tissue prior to t ransplantation. We have investigated the effects of different steps du ring the preparation and storage of embryonic rat nigral cell suspensi ons on their subsequent survival at a variety of different time points using a combination of techniques and studies. For studies concerned with the first 24 h we employed vital stains, in the period covering t he next 7 days we used in vitro cultures, and in the long term experim ent we used in vivo grafts. The results suggest that nigral cell suspe nsions may remain sufficiently viable for grafting for much longer per iods than previously reported. In addition a number of parameters whic h affect cell survival have been characterised, including the age of t he embryonic donor tissue, the use of proteolytic enzymes and the trit uration procedure used during the preparation of the suspension. The o ptimal preparation technique, therefore, uses E13-E14 embryos with the dissected ventral mesencephalon being incubated in purified 0.1% tryp sin solutions for 60 min and triturated using a flame polished Pasteur pipette. This may have important implications in improving intracereb ral transplantation for Parkinson's disease.