Changes of MDA and SOD in Brain Tissue after Secondary Brain Injury with Seawater Immersion in Rats.

AIM To investigate the variation and significance of malondialdehyde (MDA) and superoxide dismutase (SOD) in brain tissue after secondary brain injury (SBI) with seawater immersion in rats. MATERIAL AND METHODS We randomly divided 163 male Sprague Dawley rats into 4 groups, as normal (Group A), SBI (Group B), SBI with physiological saline immersion (Group C) and SBI with seawater immersion (Group D) groups. The animal model of ischemic SBI with seawater immersion was established based on the Marmarou's model of diffuse brain injury. The water content, and the MDA and SOD contents of brain tissue were detected at 1, 3, 6, 12, 24 and 48 hours after the injury. RESULTS Compared to group A, there were significant changes of various indicators in group D after injury at 1 hour after injury (P < 0.05). The water content and MDA contents in brain tissue were persistently elevated and significantly higher than that in groups B and C at each time phase (P < 0.05). The SOD content showed a persistent decline and was significantly lower than that in groups B and C at each time phase (P < 0.05). The SOD content was negatively correlated with the MDA content with a correlation coefficient of -0.992 (P < 0.01). CONCLUSION The SBI with seawater immersion is faster and more serious than the simple SBI.