Under Controlled Hypotension, Different Level Of Hypotension On Influences Of Myocardial Emzyme And Cardiac Troponin Ⅰ In The Rats

Objective:To observe the influence of different level of hypotension to myocardial emzyme and expression of cTnI in the rats under the controlled hypotension induced by sodium nitroprusside(SNP) and esmolol(ESM),to explore the rats' tolerance to different level of hypotension under the controlled hypotension.Method:42 Sprague-Dawley rats that are about three monthes old,are randomly divided into four groups:group A(n=6)is control group without induced hypotension;group B is controlled hypotension at the level of 50mmHg group,and it includes group B1(n=6)which is controlled hypotension at the level of 50mmHg and last for 30 minutes and group B2(n=6)which is controlled hypotension at the level of 50mmHg and last for 60minutes;group C is controlled hypotension at the level of 50mmHg group,and it includes group C1(n=6) which is controlled hypotension at the level of 50mmHg and last for 30 minutes and group C2(n=6)which is controlled hypotension at the level of 50mmHg and last for 60minutes;group D is controlled hypotension at the level of 50mmHg group,and it includes group D1(n=6)which is controlled hypotension at the level of 50mmHg and last for 30 minutes and group D2(n=6)which is controlled hypotension at the level of 50mmHg and last for 60minutes.Group A is continus infused 0.9% physiological saline solution(NS).Group B,C and D are induced to their target mean arterial pressure(MAP) and the sub-groups are maintained to the target time respectively with sodium nitroprusside(SNP) and esmolol(ESM).Recording vital sign of rats and doing blood gas analsy.Having a laboratory test of myocardial emzyme and detecting the cTnI with immunohisto chemical staining after 24 hours.The survival rate of the rats are also recorded.Result:1.The leve of CK-MB in the group C2 is more higher than that in the group C1(P<0.05);the level of LDH,CK,CK-MB in group C1 is the highest among that in the group A and B1(P<0.05);the level of LDH,CK,CK-MB in group C2 is the highest among that in the group A and B2(P<0.05).Because of the high death rate,the group D1 and D2 are excluded.2.The expression of cTnI in group C1 is higher than that in group B1 and group A(P<0.05);the expression of cTnI in group C2 is higher than that in group B2 and group A(P<0.05).The expression of cTnI in group C2 and is higher than that in group C1.Conclusions:1.The heart of the rats can tolerate the hypotension at the level of 50mmHg for 30 minutes to 60 minutes without significant change of myocardial emzyme and expression of cTnI under the controlled hypotension.2.When the hypotension is controlled to the level of 30 mmHg for 30min to 60min,the myocardial emzyme and expression of cTnI is increased significantly.In this case,the myocardial cell is damnified obviously and the level of damage increase as the time extend.3.The rats cann't tolerate the hypotension at the level of 25 mmHg for 30 minutes It's mortality is high.when controlled hypotension at the level of 25mmHg for 60 minutes,all the rats are dead.