限食对衰老大鼠心功能的保护作用及其机制

目的研究限食对衰老大鼠心功能的保护作用及其机制。方法选择2月龄SD大鼠10只,随机分为衰老组和限食组(60%进食量),每组5只。2组大鼠每天皮下注射D-半乳糖100mg/kg,连续给药42d建立衰老动物模型;衰老模型建立后另选5只2月龄SD大鼠设为青年组。3组行心功能检测,包括左心室内压(LVSP)、左心室舒张末压(LVEDP)、左心室压力最大上升速率(+dp/dtmax),以及血浆丙二醛水平、超氧化物歧化酶活性和左心室心肌脂褐素水平测定。结果与青年组比较,衰老组大鼠LVSP、+dp/dtmax、超氧化物歧化酶活性明显降低,LVEDP、丙二醛、脂褐素水平明显升高,差异有统计学意义(P<0.05,P<0.01);与衰老组比较,限食组LVSP(110.88±7.35)mm Hg(1mm Hg=0.133kPa)vs(70.18±19.27)mm Hg]、+dp/dtmax(2827.60±237.88)mm Hg/s vs(2365.66±99.81)mm Hg/s]和超氧化物歧化酶(115.77±10.17)U/ml vs(90.10±17.11)U/ml]活性明显升高,LVEDP(7.12±2.51)mm Hg vs(14.05±2.01)mm Hg]、丙二醛(12.54±1.66)nmol/ml vs(15.83±2.51)nmol/ml]和脂褐素(348.82±27.29)ng/mg vs(400.12±31.89)ng/mg]水平明显降低,差异有统计学意义(P<0.05,P<0.01)。结论衰老大鼠心功能有所降低,限食可能通过降低机体氧化应激水平,使脂褐素形成减少,从而改善衰老大鼠心功能。

Protective effect of dietary restriction on cardiac function in aging rats

Objective To study the protective effect of dietary restriction on cardiac function in aging rats.Methods Ten SD rats aged 2months were randomly divided into aging group and dietary restriction(60%food intake)group(5in each group).An aging rat model was established by daily subcutaneous injection of D-galactose(100mg/kg)for 42 days.Another 5SD rats aged 2months served as an adolecent group.The cardiac functions(including LVSP,LVEDP,+dp/dtmax)were detected and the plasma MDA level,SOD activity,left ventricular myocardial lipofuscin level were measured in 3groups.Results The LVSP,+dp/dtmax,SOD activity were significantly lower while the LVEDP,plasma MDA level,myocardial lipofuscin level were significantly higher in aging group than in adolecent group(P<0.05,P<0.01).The LVSP,+dp/dtmax,SOD activity were significantly higher while the LVEDP,plasma MDA level,myocardial lipofuscin level were significantly lower in dietary restriction group than in aging group(110.88±7.35 mm Hg vs 70.18±19.27 mm Hg,2827.60±237.88 mm Hg/s vs 2365.66±99.81 mm Hg/s,115.77±10.17U/ml vs 90.10±17.11U/ml,7.12±2.51 mm Hg vs 14.05±2.01 mm Hg,12.54±1.66nmol/ml vs 15.83±2.51nmol/ml,348.82±27.29ng/mg vs 400.12±31.89ng/mg,P<0.05,P<0.01).Conclusion The cardiac function decreases in aging rats.Dietary restriction can imporve their cardiac function by reducing the oxidative stress level and lipofuscin formation.