Protection Effects Of Legs Ischemic Preconditioning On Pigs-heart In Cardiopulmonary Bypass Opreation

Objective : To observe the myocardium protectionaleffects by legs ischemic preconditioning (LIPC)cardiaopulmonary bypass(CPB) operation. And to study thepossible mechanism and the relationship between the protectionand myocardium apoptosis.Methods:20 male white-jerk-pigs, weight 36-40kg ,wererandomly divided into two groups: normal control group (NC,n=10) , and legs ischemic preconditioning group (LIPC,n=10).After non-eating for 24 hours, and other jobs to observe all thenecessory items in the operation ,to finish the building ofpigs-CPB-model.①normal control group (NC, n=10) :after theCPB machionary working together with the heart beating for 45minutes, blocking the blood from the central vein and theascending aorta. The heart would stop beating in the following90 minutes of the second period , no blood from the ascendingaorta makes the long-lasting ischemia . Then in the third period,the ascending aorta would be released lasting 120 minutes. ②legs ischemic preconditioning group (LIPC,n=10): to finish thebuilding of the model just like the NC group. Then thelegs-vessels (including artery and vein) of pigs were clampedmaking 5 minutes'ischemia, and released for 10 minutes'reperfusion. the same programe would last three times, up to 45minutes. In the whole course to monitor the changes ofhemodynamics and cardiactelegraph . And to collect the bloodsamples and myocardium tissues for examining the activities ofsuperoxide dismutase (SOD), and the content ofmalondialdehyde (MDA) and LDH in the blood serum , andthe variety of tissue appearance under the light microscope andelectronic microscope ; the expression level ofapoptosis-gene-protein like bcl-2,bax etc ; the apoptosis index(AI) in the TUNEL essay .Results:From different aspects we could find the result:①There was great variety of tissue appearance between twogroups under the light microscope and electronic microscope②LIPC group had a better recovery of myocardium function thenNC group(P<0.05).③The value of SOD of group LIPC showedan increasing tendency, compared with NC group, the content ofMDA of group LIPC decreased obviously compared with NCgroup, there was obvious statistical significance(P<0.01) after120 minutes'reperfusion.④The flow cytometry showed thatLIPC group had a lower AI (the apoptosis index) than NCgroup(P<0.01); the study to the expression level of apoptosisgenic protein by flow cytometry showed that LIPC group had alower level in bax, and a higher level in bcl-2 than NCgroup(P<0.01).⑤the study to the apoptosis index (AI) in theTUNEL essay showed that LIPC group had a lower AI thanNC group(P<0.01).