Free Radical Reaction and Biological Defense Mechanism in the Pathogenesis of Prolonged Vasospasm in Experimental Subarachnoid Hemorrhage

The relationship between free radical reactions and the defense mechanisms against them was investigated in the pathogenesis of prolonged vasospasm following experimental subarachnoid hemorrhage (SAH) in dogs. The concentration of lipid peroxides in the cerebro spinal fluid (CSF) increased markedly up to the eighth day following SAH; the concentrations also rose in the arterial wall (p < 0.01) and the gray matter of the temporal lobe where the subarachnoid blood clots were (p < 0.01). On the other hand, the activity of superoxide dismutase (SOD) decreased significantly up to the eighth day after SAH (p < 0.01), and there was a gradual increase of glutathione peroxidase (GSH-px) in the CSF. In the arterial wall, there was a slight decrease in the activity of SOD, a significant decrease in the activity of GSH-px (p < 0.01), and also a significant decrease in the concentration of glutathione (p < 0.01) up to the eighth day following SAH. In conclusion, lipid peroxidation with insufficient biological defense mechanisms against it in the arterial wall, concomitant with that in the CSF, might take part in the genesis of prolonged vasospasm following SAH.