The Protective Effects Of Glucose-insulin-potassium On Brain In Rabbits With Endotoxic Shock

Objective: To investigate the protective effects and possible mechanism of GIK on the brain of endotoxin-induced shock rabbits.Methods:Thirty New Zealand white rabbits were equally and randomly divided into NS group,ES group and GIK group.Rabbits in NS group were infusioned of compound sodium chloride（5ml/kg.h）;ES group and GIK group were given intravenous injection of LPS（0.5 mg / kg）to establish endotoxin shock model,followed by intravenous injection of compound sodium chloride and GIK（5ml/kg.h for 6 hours）respectively.During the experiment,measured the vital signs（mean arterial pressure,respiratory rate,temperature）,blood glucose,blood gas analysis index（PH,PaCO₂,serum potassium,lactic acid）at different time points,detected the concentration of NSE in serum by ELISA method.At the end of the experiment,the rabbits were killed and the brain tissue was taken immediately.Part of the left brain was used to prepare 10%homogenate,then detected the concentrations of oxidative indexes（H2O₂,NO,i NOS,MDA）and antioxidant indexes（SOD,T-AOC）,measured the activities of Na⁺-K⁺-ATP enzyme and Ca²⁺-Mg²⁺-ATP;The residual brain tissue was used to weigh dry and wet weight.The morphological changes of the right brain were observed by light microscope and electron microscope.Results: 1.Compared with NS group,the levels of mean arterial pressure,PH,PaCO₂ were obviously decreased and the levels of lactic acid,respiratory frequency,temperature were increased significantly in rabbits after injected of LPS（P < 0.05）.In the course of treatment,the levels of meanarterial pressure and lactic acid in ES group and GIK group were gradually increased（P < 0.05）.Compared with ES group,the level of mean arterial pressure obviously increased and lactic acid evidently decreased in GIK group（P < 0.05）,there was no significant difference in other indicators（P >0.05）.2.Compared with NS group,the concentrations of oxidation indexes in brain homogenate,the level of NSE in serum,brain water content in ES group and GIK group were significantly increased（P < 0.05）,the concentrations of antioxidant indexes,the activities of Na⁺-K⁺-ATP enzyme and Ca²⁺-Mg²⁺-ATP enzyme were evidently decreased（P < 0.05）.Compared with ES group,the levels of oxidation indexes,NSE,brain water content in GIK group were significantly decreased（P < 0.05）,while the concentrations of antioxidant index,the activities of Na⁺-K⁺-ATP enzyme and Ca²⁺-Mg²⁺-ATP enzyme were significantly increased（P < 0.05）.3.Pathological observation showed that there was no abnormality in NS group,the damage of brain cells and mitochondria was obviously in ES group and GIK group,however,the pathological damage in GIK group was significantly lower than that in ES group.Conclusion: GIK has protective effects on the brain tissue of endotoxic shock rabbits,which may be related to improve hemodynamics,inhibite oxidative stress and reduce mitochondria damage.