重复+Gz暴露后大鼠心肌儿茶酚胺类物质含量的变化以及低G预适应和茶多酚的防护作用

目的观察重复+Gz暴露是否引起心肌组织儿茶酚胺类物质代谢异常以及低G预适应和天然抗氧化剂茶多酚(TP)的防护作用. 方法 32只雄性Wistar 大鼠随机分为4组(n=8) A组(对照组),仅受到+1 Gz 作用5 min; B组(+Gz应激组), +10 Gz峰值暴露30 s/次,重复5次/d,间隔为+1 Gz 1 min, 3 d/wk, 共3 wk; C组(低G预适应组), +Gz应激条件同B组,但+10 Gz 暴露前1 h 受到+2 Gz 作用5 min;D组(TP防护组),+Gz应激条件同B组,但+10 Gz 暴露前1 h灌胃给予茶多酚200 mg/kg.于末次+Gz暴露的次日上午将各组大鼠断头处死,迅速摘取心脏置液氮冷藏,用高效液相色谱电化学检测法测定各组大鼠心肌儿茶酚胺类物质含量, 包括去甲肾上腺素(NA),肾上腺素(AD),多巴胺(DA),5-羟色胺(5-HT).结果与A组相比,B组心肌AD水平显著升高(P<0.01),但NA,DA,5-HT含量无明显差别.与B组相比,C、D组心肌AD、5-HT含量明显降低,而D组DA水平显著升高.结论重复+10 Gz暴露引起大鼠心肌儿茶酚胺类物质代谢异常,主要是AD水平显著升高;低G预适应和天然抗氧化剂TP具有明显的防护作用.

Changes of Cardiac Catecholamines in Rats after Repeated +Gz Exposures and Protective Effects of Low-G Preconditioning and Tea Polyphenols

Objective To observe whether repeated +Gz exposures could induce metabolic disorder of cardiac catecholamines in rats as well as the protective effects of low G preconditioning and tea polyphenols(TP). Method Thirty two male Wistar rats were randomly divided into 4 groups (n=8): group A(control),only submitted to +1 Gz 5 min; group B(+10 Gz stress), exposed to +10 Gz 30 s ,5 times/d with +1 Gz 1 min interval,3 d/wk, for 3 wk in total; group C(low G preconditioning), +Gz stress parameters were the same to that of group B,but the rats were submitted to +2 Gz 5 min 1 h prior to +10 Gz exposure;group D(TP protection),+Gz stress parameters were the same to that of group B,but TP was given orally to the rats at the dose of 200 mg/kg 1 h prior to +10 Gz exposure. These animals were decapitated on the next morning of the last centrifuge run, and the hearts were taken out and stored in liquid nitrogen immediately. The contents of noradrenaline (NA),adrenaline(AD), dopamine (DA) and serotonin (5 HT) in myocardial tissue were determinedusing HPLC with electrochemical detector. Result Compared with group A, AD level in group B increased significantly(P<0.01),but there were no significant differences of NA,DA and 5 HT contents between the two groups. Compared with group B, the myocardial contents of AD and 5 HT were decreased significantly in group C and D(P<0.01),while myocardial DA concentration in group D increased significantly(P<0.01). Conclusion Repeated +10 Gz exposures could induce metabolic disorder of catecholamines in rat heart,especially the increase of AD level.Low G preconditioning and natural antioxidant TP had significant protective effects.