Objective To observe the effect of midazolam on changes in cytokines and pathology during myocardial ischemia and reperfusion(I/R).Methods Twenty-four rabbits were randomly divided into three groups:sham operation group (group C,n=8),ischemia reperfusion group(group IR,n=8),midazolam group (group M,n=8),TNF-α and IL-6 in serum were measured at the following points:5 min before occlusion (I 0),30 min after occlusion(I 1),1 h(R 1)and 3 h(R 2)after reperfusion.Cardiac homogenate was taken at the end of reperfusion ,then TNF-α and IL-6 in it were measured.The serum activity of LDH and CPK were measured at I 0 and R 2 in three groups.The pathological changes were investigated under light and electron microscope.Results ①Changes of cytokines in serum and cardiac homogenate:in group M,serum TNF-α increased at I 1 and R 1,and decreased at R 2;serum IL-6 increased at R 2;Myocardial TNF-α and IL-6 were significantly lower than those in group IR( P <0 05).In group IR,serum TNF-α reached it's peak at R 1 and decreased a little at R 2,but it was still higher than that in group C and M( P <0 05),serum IL-6 increased significantly at R 1( P <0 05),and kept at a high level during reperfusion;compared with group C and M,the levels of TNF-α and IL-6 in cardiac homogenate were higher( P <0 05).
②Changes of LDH and CPK:the activity of LDH and CPK increased significantly at R 2 in group M and IR,the increases were greater in group IR and smaller in group M.③Pathological changes:under light microscope,mild myocardium edema and a few inflammatory cells were found in group M.Such changes were serious in group IR.Under electron microscope,mild swollen mitochondria with clear crest were found in group M, while in group IR irregular myofilaments and swollen mitochondria with broken or disappeared crest were observed.Conclusion Midazolam could inhibit the production of serum and myocardial TNF-α and IL-6,then midazolam could protect heart tissue during myocardial ischemia and reperfusion. <