盐酸戊乙奎醚对大鼠心肌缺血／再灌注损伤保护作用的研究

The research on protective effect of penehyclidine hydrochloride in rats with myocardial ischemia/reperfusion injury

目的比较不同剂量盐酸戊乙奎醚（PHC）预处理对大鼠心肌缺血／再灌注（I／R）损伤的保护作用。方法健康雄性Wistar大鼠48只，按随机数字表法分为空白对照组（Sham）、空白＋1．0mg／kgPHC对照组（Sham＋H—PHC组）、I／R组、I／R＋0．1mg／kgPHC预处理组（I／R＋L—PHC组）、I／R＋0．3mg／kgPHC预处理组（I／R＋M—PHC组）及I／R＋1．0mg／kgPHC预处理组（I／R＋H—PHC组）6组，每组8只。采用冠状动脉结扎制备心肌I／R损伤模型，于制模前30min给予相应剂量PHC进行预处理。再灌注3h后记录左室舒张期末压（LVEDP）、左室收缩期末压（LVESP）、射血分数（EF）和短轴缩短率（FS）；测定血清天冬氨酸转氨酶（AST）、肌酸激酶同工酶（CK—MB）、乳酸脱氢酶（LDH）含量。处死大鼠取心脏，测定心肌缺血面积（AAR）及梗死面积（AI），计算AI／AAR比值；电镜下观察心肌纤维超微结构改变。结果与Sham组和Sham＋H—PHC组比较，I／R后各组大鼠均表现为LVEDP增高，LVESP、EF及Fs降低，AST、CK—MB、LDH含量升高，AI／AAR增加。与I／R组比较，不同剂量PHC预处理组LVEDP下降，LVESP、EF、FS升高，AST、CK—MB、LDH含量及AI／AAR比值下降，以中、大剂量PHC组改善最明显[LVEDP（mmHg，1mmHg=0．133kPa）：11．33±1．17、9．85±1．09比15．82±1．79，LVESP（mmHg）：98．9±10．6、112．8±10．0比87．8±9．2，EF：0．681±0．074、0．741±0．070比0．569±0．072，FS：（42．4±4．6）％、（46．0±5．1）％比（36.8±3．9）％，AST（U／L）：386．97±80．65、298．31±54．88比603．47±173．66，CK—MB（U／L）：3．12±0．84、2．88±0．72比7．14±1．54，LDH（U／L）：1784．23±488．49、1629．37±436．34比2489．14±460．80，AI／AAR比值：0．284±0．014、0．223±0．008比0．377±0．011，均P〈0．05]；中、大剂量PHC组比较，仅LVEDP、LYESP和AI／AAR比值差异有统计学意义（均P〈0．05），其余指标比较均P〉0．05。电镜下观察可见：I／R损伤后线粒体明显肿胀，被膜不完整，线粒体嵴消失，结构不完整；中、大剂量PHC预处理组线粒体肿胀减轻，被膜逐渐完整，线粒体嵴可见，结构完整，以大剂量PHC预处理组效果最好，基本接近正常。结论PHC预处理对心肌I／R损伤有明显的保护作用。中剂量PHC（0-3mg／kg）和大剂量PHC（1．0mg／kg）对心肌I／R损伤的保护作用明显优于小剂量PHC（0．1mg／kg），大剂量PHC的保护作用优于中剂量PHC。

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, LVEDPwas 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, 1 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, EF： 0.681 ± 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/AAR： 0.284± 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-PI-IC 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.