Antioxidant enzymatic activities after experimental subarachnoid hemorrhage in rats

Lipid peroxidation has been hypotesized as one of possible factors involved in the pathogenesis of neuronal damage and delayed vasospasm after subarachnoid hemorrhage. In the brain there are anti-oxidant enzymatic systems which act as scavengers of superoxides and free radicals. In the present study the pattern of enzymatic anti-oxidant activities (Cu-Zn and Mn superoxide dismutase, and glutathione peroxidase) was investigated in an experimental model of subarachnoid hemorrhage in the rat in order to verify whether the hemorrhagic insult may be responsible for an impairment of such anti-oxidant systems. Enzymatic activities were assayed in three different rat brain areas (cerebral cortex, hippocampus and brain stem) of sham-operated and at 30 min, 1, 6 and 48 h after subarachnoid hemorrhage induction. After the hemorrhage induction the Cu-Zn superoxide dismutase activity in cerebral cortex was significantly reduced at all the set times (p < .05), while Mn-superoxide dismutase activity was significantly decreased since 1 h (p < .05) until 48 h (p < .05). Glutathione peroxidase activity was significantly reduced only in the late phase (48 h) of subarachnoid hemorrhage (p < .01). In the hippocampus, all enzymatic activities were significantly reduced in the late phase. In the brain stem Cu-Zn superoxide dismutase was significantly impaired at 1 and 6 h (p < .05) after subarachnoid hemorrhage induction, while in the late phase (48 h) reached the control value. The mitochondrial Mn-superoxide dismutase was significantly reduced since 1 h (p < .05) until 48 h (p < .02) after subarachnoid hemorrhage.(ABSTRACT TRUNCATED AT 250 WORDS)