Effects of selective mild cerebral hypothermia on endogenous anti-injury mechanism in brain tissue after cardiac arrest and resuscitation

Objective To study the effects of selective mild cerebral hypothermia on endogenous anti-injury mechanism in brain tissue after cardiac arrest and resuscitation. Methods Fifteen healthy mongrel dogs of both sexes were anesthetized and intubated. Cardiac arrest was induced by potassium cardioplegia and cross-clamping of aorta, vena cava superior and inferior and azygos vein and maintained for 18min. The animals were randomly divided into 3 groups: group A, in which no cardiac arrest was induced, served as control ( n = 4) ; in group B animals received routine cerebral resuscitation ( n = 5) ; in group C animals received selective mild cerebral hypothermia (34℃±0.5℃) and routine cerebral resuscitation ( n = 6) . After successful resuscitation, the animals were observed for 8 hours. At the end of the experiment the parietal cerebral cortex was removed for determination of MDA, GSH, LA, FFA content and activities of SOD(T-SOD, Mn-SOD, Cu-ZnSOD) and GSH-Px. Results FFA and LA content of brain tissue in group B was significantly higher than those in group A (P 0. 05). GSH, GSH-Px content and T-SOD, Mn-SOD, Cu-ZnSOD activities decreased significantly in group B as compared with those in group A( P0.05 or 0.01). GSH content and T-SOD, Cu-ZnSOD activities in group C were significantly higher in group C than those in group B. There was no significant difference in MDA, FFA and LA between group C and B. Conclusion Mild cerebral hypothermia up-regulates anti-injury mechanism in brain tissue following cardiac arrest and resuscitation and may be beneficial to cerebral resuscitation.