TOXIC EFFECT OF HEMOGLOBIN ON SPINAL-CORD NEURONS IN CULTURE

The vulnerability of spinal cord neurons to hemoglobin was quantitativ ely assessed in primary cultures derived from fetal mice. Exposure to hemoglobin for 28 h in a serum-free medium resulted in concentration-d ependent neuronal death, with an EC50 of 0.9 mu M; glia were not injur ed, Neuronal death was decreased by the ferric iron chelator deferoxam ine, the a-tocopherol analogue Trolox C, ascorbate, and exogenous cata lase, but was potentiated by superoxide dismutase, Neuronal death was also increased by depletion of cellular glutathione with the gamma-glu tamylcysteine synthetase inhibitor buthionine sulfoxamine; inhibition of endogenous catalase with 3-amino-1,2,4-triazole had no significant effect. These results suggest that hemoglobin is toxic to spinal neuro ns via an iron-dependent, oxidative mechanism involving a hydrogen per oxide intermediate, and support the hypothesis that hemoglobin release may contribute to neuronal loss after spinal cord trauma.