Fetal porcine ventral mesencephalon grafts: dissection procedure and cellular characterization in culture

The objective of this study was to develop an optimal dissection procedure for fetal porcine ventral mesencephalon (VM) grafts and to characterize the cellular composition of such an explant, in particular with respect to the dopaminergic and GABAergic components. We have used a monolayer cell culture system to study and identify the various VM cell types. The in vitro development of the fetal VM cells and the effect of the addition of brain-derived neurotrophic factor (BDNF) was investigated during a culture period of 5 days. Extracellular dopamine levels were measured by means of high performance liquid chromatography (HPLC) with electrochemical detection (LCEC). Our results indicate that the ratio of dopaminergic to GABAergic neurons changed in favour of the dopaminergic component when a more selective dissection technique was used. Although addition of BDNF to the cultures appeared to exert trophic influences on all the cellular components of pig fetal VM, this effect was most pronounced on the TH-positive cells. Highest extracellular DA levels were found in the VM culture with the addition of BDNF and when a more selective dissection method was used. Our in vitro findings suggest that porcine fetal dopaminergic cells retain their potential for development and outgrowth after proper explantation and dissociation. Anticipating on the results of ongoing transplantation studies in rat, they suggest that pig fetal VM can be a suitable alternative for the use of fetal human VM as a graft for Parkinson's disease.