The research on protective effect of penehyclidine hydrochloride in rats with myocardial ischemia/reperfusion injury / 中华危重病急救医学

ABSTRACT

Objective To compare the protective effect of different dose of penehyclidine hydrochloride (PHC) in rats with myocardial ischemia/reperfusion (I/R) injury.Methods Forty-eight healthy male Wistar rats were randomly divided into six groups (n =8 each)sham group,sham + 1.0 mg/kg PHC group (sham + H-PHC group),I/R group,I/R + 0.1 mg/kg PHC preconditioning group (I/R + L-PHC group),I/R + 0.3 mg/kg PHC preconditioning group (I/R + M-PHC group),and I/R + 1.0 mg/kg PHC preconditioning group (I/R + H-PHC group).I/R injury model was reproduced by ligation followed by release of the coronary artery,and PHC in different dosages was given at 30 minutes before model reproduction.At 3 hours after reperfusion,the left ventricular end-diastolic pressure (LVEDP),left ventricular end-systolic pressure (LVESP),ejection fraction (EF),and fractional shortening (FS) were recorded.The levels of aspertate aminotransferase (AST),MB isoenzyme of creatine kinase (CK-MB),and lactate dehydrogenase (LDH) were determined.The myocardial tissues were harvested for the determination of the area at risk (AAR) and the infarct area (AI),and the percentage of AI/AAR was calculated.The examination of myocardial fiber was performed with electron microscopy.Results Compared with sham and sham + H-PHC groups,LVEDP was increased in I/R groups,LVESP,EF and FS were decreased,and the levels of AST,CK-MB and LDH,as well as the AI/AAR were increased.Compared with I/R group,in pretreatment groups with different doses of PHC,LVEDP was decreased,LVESP,EF and FS were increased,the levels of AST,CK-MB,LDH,and AI/AAR were also decreased,especially in I/R+M-PHC and I/R+H-PHC groups [LVEDP (mmHg,I mmHg =0.133 kPa)11.33± 1.17,9.85± 1.09 vs.15.82 ± 1.79,LVESP (mmHg)98.9 ± 10.6,112.8 ± 10.0 vs.87.8 ± 9.2,EF0.681 ± 0.074,0.741 ± 0.070 vs.0.569 ± 0.072,FS(42.4 ± 4.6)％,(46.0 ± 5.1)％ vs.(36.8 ± 3.9)％,AST (U/L)386.97 ± 80.65,298.31 ± 54.88 vs.603.47 ± 173.66,CK-MB (U/L)3.12 ± 0.84,2.88 ± 0.72 vs.7.14 ± 1.54,LDH (U/L)1 784.23 ± 488.49,1 629.37 ± 436.34 vs.2 489.14 ± 460.80,AI/AAR0.284 ± 0.014,0.223 ± 0.008 vs.0.377 ± 0.011,all P ＜ 0.05].There was significant difference in LVEDP,LVESP,and AI/AAR between I/R + M-PHC group and I/R + H-PHC group (all P ＜ 0.05),and no significant difference in other parameters (all P ＞ 0.05).It was showed by electron microscopic examination that after I/R injury,the myocyte mitochondria membranes were broken,mitochondria were markedly swollen,mitochondrial cristae disappeared;however in I/R+M-PHC and I/R+H-PHC groups,mitochondrial swelling was mild,the capsule was more or less intact,mitochondrial cristae were partly visible,the structure was complete,especially in the group I/R+H-PHC,and the mitochondrial structure was close to normal.Conclusions PHC could protect myocardial from I/R injury.Mid dose of PHC (0.3 mg/kg) and high dose of PHC (1.0 mg/kg) could provide better protective effect than low dose of PHC (0.1 mg/kg),and high dose of PHC is better in effect than the middle dose.