普萘洛尔预处理对缺血再灌注肥厚心肌超微结构形态的影响

Propranolol pretreatment protects ischemic hypertrophied myocardium in rat

目的探讨围手术期应用普萘洛尔预处理对肥厚心肌再灌注损伤的保护作用。方法36只雄性8周龄SD大鼠,随机分为正常心肌组、肥厚心肌组及普萘洛尔组。腹主动脉缩窄制备大鼠心肌肥厚模型,采用离体工作心脏灌流模型,缺血再灌注实验结束后取心肌组织观察超微结构并形态学定量测定线粒体损伤程度。结果各组大鼠均全部存活,切口无感染、渗血,服药期间无死亡。肥厚心肌组、普萘洛尔组心脏重量指数明显高于正常心肌组(P<0.01),肥厚心肌组与普萘洛尔组差异无统计学意义。超微结构显示普萘洛尔组心肌细胞损伤较对照组轻。心肌细胞线粒体形态学定量测定显示普萘洛尔组心肌细胞线粒体损伤较肥厚心肌组明显减轻(P<0.01)。结论普萘洛尔术前预处理较好地保护了心肌超微结构形态。而术前应用普萘洛尔减轻心肌线粒体损伤,明显保护再灌注期间线粒体良好的呼吸功能,可能是减轻肥厚心肌再灌注损伤的一个重要机制。

Objective This study was carried out to investigate the myocardial morphology effect of propranolol pretreatment on the isolated retroperfused rat hearts made hypertrophy by aortic banding. Methods Male Sprague-Dawley rats （age, 8 weeks） were subjected either to constriction of the abdominal aorta just above the renal artery or to sham operation. The rats were studied at 14-15 weeks of age ,the hearts were subjected to 2h of global ischemia followed by lh of repeIfusion, with propranolol pre-ischemia （ daily 10 mg/kg,for 10 days） or unpretreatment. Aniamls completing the experiment included the propranolol pretreated group （n=12）,the unpretreated group（ n=12 ） and normal age-matched control group （n=12）. Myocardial morphology were assessed in this study. Results The left ventricular weight/body weight ratio in the hypertrophied hearts was（3.77±0.04）g/kg versus （2.10±0.03）g/kg in the age-matched controls（P〈0.01 ）.Propranolol reduces or clelays the damage to the hypertrophied myocardiad cells. Morphometric study of electron micrographs demonstrated that mitochondrial swelling was distinctly less in propranolol-treated than in untreated rats（P〈0.01 ）. Conclusion Propranolol pretreatment in hypertrophied hearts provides protectior of hypertrophied rat hearts. This effect is maximal in protecting the mitochondria, thereby suggesting that mitochondrial salvage may play an important role in propranolol pretreatment＇s abillity to protect ischemic hypertrophied myocardium.