Effects of glial cell line-derived neurotrophic factor (GDNF) on mouse fetal ventral mesencephalic tissue

Sammanfattning: The symptoms of Parkinson's disease occur due to degeneration of dopamine neurons in substantia nigra. It has been demonstrated that glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor when it comes to protect and enhance survival of dopamine neurons in animal models of Parkinson's disease. The aim of this study was to evaluate short- and long-term effects of GDNF on survival and nerve fiber outgrowth of dopamine cells and astrocytic migration in mouse fetal ventral mesencephalic (VM) tissue. Primary tissue cultures were made of mouse fetal VM tissue and evaluated at 7 and 21 days in vitro (DIV) in terms of dopaminergic nerve fiber outgrowth and astrocytic migration when developed with GDNF present, partially, or completely absent. The results revealed that VM tissue cultured in the absence of GDNF did not exhibit any significant differences in migration of astrocytes or dopaminergic nerve fiber outgrowth neither after 7 DIV nor after 21 DIV, when compared with tissue cultured with GDNF present. Migration of astrocytes and dopaminergic nerve fiber outgrowth reached longer distances when tissue was left to develop for 21 DIV in comparison with 7 DIV. In order to study the long-term effects of GDNF, mouse fetal dopaminergic tissue was transplanted into the ventricles of adult mice and evaluated after 6 months. No surviving dopamine neurons were present in the absence of GDNF. In contrast dopamine neurons developed with GDNF did survive, indicating that GDNF is an essential neurotrophic factor when it comes to long-term dopamine cell survival. More cases have to be assessed in the future in order to strengthen the findings. Thus, transplanted dopamine neurons will be assessed after 3 and 12 months in order to map out when dopamine neurons deprived of GDNF undergo degeneration.