间歇有氧运动对慢性心衰大鼠肾脏功能和肾脏AQP2表达的影响及可能机制

The Effect of Aerobic Interval Training on Renal Function and Renal Aquaporin-2 Expression in Rats with Chronic Heart Failure and Its Mechanism

目的:探讨运动干预对慢性心力衰竭(CHF)大鼠肾脏功能和肾脏AQP2表达的影响,揭示运动改善CHF肾脏功能的可能机制。方法:选取雄性SD大鼠36只,随机分为假手术组(Sham),慢性心力衰竭组(CHF),慢性心力衰竭+间歇有氧运动组(AIT-CHF),每组12只。Sham组大鼠常规饲养,CHF采用心脏左冠状动脉前降支(LADCA)结扎法,建立CHF模型。AIT-CHF组大鼠在术后4周开始运动。AIT-CHF组起始运动速度为10 m/min,运动时间为10 min,速度逐渐增至25 m/min,运动7 min后,间歇3 min,其速度为15 m/min,之后依次交替进行,运动总时间为60 min。以上训练方案每周5 d,训练至8周结束。训练结束后,采用血流动力学和紫外分光光度法测定各组大鼠心肾功能变化。利用天狼猩红染色和免疫组化方法分别检测肾脏间质胶原和AQP2表达定位。运用Western Blot和Real time-PCR法分别检测肾脏AQP2蛋白和mRNA表达变化。Western Blot法检测各组大鼠肾脏p-NF-κBp65蛋白含量。结果:与Sham组比较,CHF组大鼠LVEDP升高,LVSP和±dp/dt max显著降低;CVF升高,血清BUN和sCr表达增高,AVP活性显著增强;CHF后可见肾脏集合管主细胞膜和胞浆中AQP2阳性染色,并且AQP2蛋白和mRNA表达显著升高,同时肾脏中p-NF-κBp65蛋白表达增多。与CHF组比较,AIT可显著降低AIT-CHF组大鼠LVEDP,升高LVSP和±dp/dt max;降低CVF,减少血清BUN和sCr表达,降低AVP活性表达;显著减少肾脏AQP2蛋白和mRNA表达,同时降低肾脏p-NF-κBp65蛋白表达。结论:1)间歇有氧运动通过降低血液中BUN和sCr表达,减少肾脏间质胶原沉积,缓解CHF大鼠肾脏功能紊乱。2)间歇有氧运动通过降低AVP活性,减少AQP2基因和蛋白表达,减缓CHF大鼠肾脏水潴留。3)间歇有氧运动干预改善CHF大鼠肾脏功能的机制可能与NF-κB信号转导通路有关。

Objective： This paper aims at exploring the effects of aerobic interval training（ AIT） on renal function and renal aquaporin- 2（ AQP2） expression in rats with chronic heart failure（ CHF） and investigating the possible mechanism of AIT improving renal dysfunction in CHF rats. Methods： Thirty-six male Sprague Dawley rats were randomly divided into three groups： Sham,CHF,and CHF combined AIT（ AIT-CHF） groups（ n = 12）.The CHF model was established by ligating the left anterior descending coronary artery（ LADCA） of rats. Four weeks after surgery,rats in AIT-CHF group underwent 8 weeks treadmill exercise training. Initially,rats in AITCHF group were exposed to adaptive exercise training at 10 m /min for 10 min,and then the exercise speed gradually increased to 25 m /min,and the time was 7 min,the interval rest was 3 min and rest speed was 15 m /min,both of exercise and interval rest changed alternately,60 min in total. This exercise training was performed 5 days per week,8 weeks in total. Rats＇ cardiac and renal functions were tested by haemodynamic parameters and spec-trophotometry. Pathological change in renal tissues was evaluated after Sirius red staining,and the collagen volume fraction（ CVF） was calculated. The localizations of AQP2 expression was determined by immunohistochemistry.The protein and mRNA expression of AQP2 were detected by Western blot and quantitative real time-PCR,respectively. The protein expression of p-NF-κBp65 was examined by Western blot. Results： Compared with Sham group,left ventricular end-diastolic pressure（ LVEDP） in CHF group increased while LVSP and ± dp /dt max decreased. When CVF increased,blood urea nitrogen（ BUN）,creatinine（ sCr） in serum,and activity of arginine vasopressin（ AVP） increased. AQP2 in renal collecting duct chief cell membrane and endochylema was positively stained. The protein and mRNA expressions of AQP2 increased. p-NF-κBp65 expression increased. Compared with CHF group,rats＇ LVEDP in AIT-CHF group decreased while their LVSP and ± dp /dt max increased. When CVF decreased,serum BUN,sCr and AVP activity decreased. Also after exercise,protein and mRNA expressions of AQP2,and protein expression of p-NF-κBp65 in renal tissue decreased. Conclusions： 1） Aerobic interval training can significantly improve the renal dysfunction in CHF rats by decreasing the expression of serum BUN and sCr,as well as renal interstitial collagen deposition. 2） Aerobic interval training significantly ameliorates water retention by reducing AVP activity and decreasing the gene and protein expression of AQP2. 3） The underlying mechanism of exercise improving renal function may be related to NF-κB signaling pathway.