| OBJECTIVE Probing into the mechenism of insulin protective effect on brain tissue in cerebral ischemia reperfusion. METHODS Rats were subjected to cerebral ischemia by bilateral ligation of the common carotid arteries for 30 minutes and then reperfusion for 2 hours. Thirty rats were randomly divided into five groups: sham group (group A) undergoing all surgical precedures but ischemia; normal saline group (group B) ; insulin group which received seperately with insulin only 2. HLJ/kg, (group C); insulin and glucose groups (groupD) with low dose insulin ,2.1IU/kg; group E with high dose insulin , 4. 5IU/kg. After completing the required precedures, the samples of brain tissues were taken to measure the contents of lipid peroxide malondialdehyde(MDA), the activities of superoxide dismutase (SOD) and ATP-ase, and to observe the ultrastructure of cortex .After that, insulin's influnce on above index was observed. RESULTS (1) Blood glucose level in group C was lower than inthe other groups (P<0.01). (2) Group C is insignificantly different from group D(P>0. 05) on every index. Low dose insulin (2.1IU/kg) can decrease the content of MDA (P<0. 05), elevated the activity of SOD (P<0.05), and suspressed the reduction of ATP-ase activity (P<0.05) to certain content in the ischemia-reperfusion brain of rats, while high dose insulin (4. 5IU/kg) have the more significant differences (P<0. 01). CONCLUSION Insulin attenuates cerebral ischemia-reperfusion damage independent of its hypoglycemic effect, high dose is more effective than low one. Insulin protect the brain tissue may by inhibiting lipid peroxidation, renovating the cell membrane and mitochondria membrane and enhancing the activity of ATP-ase. |
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