PROTECTION FROM OXIDATION ENHANCES THE SURVIVAL OF CULTURED MESENCEPHALIC NEURONS

Oxidative stress has been linked to the destruction of dopaminergic ne urons in the substantia nigra and may be a significant factor in both Parkinson's disease and MPTP toxicity. Using primary cultures of embry onic rat mesencephalon and standard immunocytochemical techniques, we have examined the survival of tyrosine hydroxylase-containing (TH+) ne urons cultured in the presence of antioxidants and/or in an environmen t of low oxygen partial pressure. The number of TH+ neurons increased approximately twofold if superoxide dismutase, glutathione peroxidase (GP), or N-acetyl cysteine (NAC) were added to the culture media. Expo sure of the neurons to a 5% oxygen environment (38 torr, i.e., 38 mm H g) also increased the survival of TH+ neurons by about twofold. A dram atic enhancement of survival, however, was seen when NAC was used in c ombination with the 5% oxygen environment. In this case, the number of TH+ neurons increased fourfold from nontreated controls. Morphologica l changes were also noted. GP increased the average neurite length whi le NAC increased the average area of the cell body in the TH+ neuron. These results suggest that manipulation of oxidative conditions by cha nging the ambient O-2 tension or the level of antioxidants promotes su rvival of TH+ neurons in culture and may have implications for transpl antation therapies in Parkinson's disease.