Abstract: Protective Effect of N-acetylcysteine on Brain Injury Induced by Cardiopulmonary Bypass in Rats CAO Huijuan, ZHOU Jin , ZHANG Tie-zheng, SUN Ying-jie, YAO Jing. Department of Anesthesiology, The General Hospital of ShenYang Military Region, Shenyang 110840,China Abstract Objective :To investigate the protective effect of N-acetylcysteine (NAC) on brain injury induced by cardiopulmonary bypass (CPB) in a rat model. Methods:Twenty-four adult male Sprague-Dawley rats were randomly divided into three groups ( eight per group ) , including sham-operated control group(group S)，vehicle control group (group C), CPB plus NAC group (group N).Rats in group N were treated with NAC 100 mg／kg into CPB prime followed by infusion at 20 mg/(kg?h) until the cessation of CPB,which in group C were treated with the same volume of natural saline. The CPB model of rat was established. The animals of group C and group N underwent one hour CPB and were observed two hours later. The samples of plasma and brain tissue were collected at two hour after CPB. The plasma levels of neuron specific enolase (NSE)，S-100β protein，tumor necrosis factor -α (TNF-α),interleukin-6 (IL-6) were determined.The contents of brain tissue of malondialdehyde (MDA) and glutathione peroxidase (GSH-px) were determined.The ultrastructure of hippocampal neuron was also examined under an electron microscope. Results :The plasma levels of NSE，S-100β protein ,TNF-α,IL-6 of group N were significantly better than those of group C. The contents of brain tissue of MDA and GSH-px of group N were significantly better than those of group C. Compared with group C ,the damage degree of ultrastructure of hippocampal neuron of group N significantly reduced. Conclusion:NAC can reduce brain injury induced by CPB in a rat model by antioxidant and anti-inflammatory mechanism. Keywords N-acetylcysteine; Cardiopulmonary bypass; Neuron specific enolase ; S-100βprotein

Key words: N-acetylcysteine, Cardiopulmonary bypass, Neuron specific enolase, S-100βprotein