雄激素受体在抗阻和耐力训练提高大鼠运动能力中的作用

Effects of Androgen Receptor on the Promotion of Exercise Performance of Rats Induced by Resistance and Endurance Trainings

目的:采用雄激素受体(AR)阻断剂氟他胺(Flutamide)研究AR对耐力和抗阻训练大鼠运动能力的影响及机制。方法:6周龄SD雄性大鼠随机分为6组(每组n=8):安静对照组(C)、氟他胺组(F)、抗阻训练组(R)、抗阻训练+氟他胺组(R+F)、耐力训练组(E)和耐力训练+氟他胺组(E+F)。E、E+F组大鼠进行中等强度(速度20 m/min,1 h/日)的跑台耐力训练,而R、R+F组大鼠进行递增负荷的爬梯抗阻训练(起始负重为40%体重,每2天递增10%体重,直至120%体重,3组/d,4次/组,组间间隔20 s),均为每周训练6 d,持续3周。检测大鼠的体重、力量(包括最大力量和速度力量)和耐力;ELISA检测血清睾酮水平;蒽酮法检测腓肠肌和比目鱼肌的肌糖原含量;Western Blot检测腓肠肌和比目鱼肌的AR、肌球蛋白重链(MHC,反映肌肉内在收缩力)、快肌球蛋白fs-myosin(反映快肌纤维含量)和慢肌钙蛋白ss-TnT(反映慢肌纤维含量)的蛋白水平。结果:(1)与C组比较,R组大鼠的最大力量和速度力量增加,E组大鼠的耐力增加;R+F组与R组比较,大鼠最大力量和速度力量降低;但E+F组与E组比较,大鼠耐力无变化;(2)与C组比较,R组大鼠腓肠肌的相对质量、fs-myosin和MHC的蛋白水平以及肌糖原含量增加,E组大鼠比目鱼肌的相对质量、ss-TnT和MHC的蛋白水平以及肌糖原含量增加。R+F组与R组比较,上述增加的腓肠肌各指标均被逆转;而E+F组与E组比较,上述增加的比目鱼肌各指标仅ss-TnT未被逆转。结论:抗阻训练增强大鼠最大力量和速度力量的作用是通过AR介导的,其机制与腓肠肌的相对质量、快肌纤维含量、内在收缩力和肌糖原含量的增加有关。但耐力训练增强大鼠耐力的作用可能与AR无关。

Objective To detect the effect of androgen receptor（AR） on the performance of ratswith endurance and resistance trainings using AR inhibitor--flutamide and explore its mechanism.Methods Forty-eight six-week-old male Sprague-Dawley rats were randomly divided into a control（C） group,a flutamide（F） group,a resistance training（R） group,a resistance training＋flutamide（R＋F）group,an endurance exercise（E） group and an endurance exercise＋flutamide（E＋F） group,each of 8.The rats of E and E＋F groups participated in moderate-intensity aerobic exercise on a treadmill at aspeed of 20 m/min for 1 h every time,while those of R and R＋F groups underwent resistance trainingwith gradually increasing intensity,with the initial load 40% of the rat＇body weight and increasing pro-gressively at 10% every 2 days until 120% of its body weight,3 sets per day,4 repetitions per setwith an interval of 20 s. All the exercise groups undertook endurance training or resistance training for 3 weeks,6 days per week. The weight,strength（including the maximum strength and speed-strength） and endurance of all the rats were examined. The serum testosterone level was detected us-ing enzyme-linked immunosorbent assay（ELISA）,while the content of muscle glycogen in gastrocnemiusand soleus was determined using the anthrone method. The protein level of AR,myosin heavy chain（MHC）,fast switch myosin（fs-myosin,reflecting the fast switch fiber level） and slow switch troponin T（ss-TnT,reflecting the slow switch fiber level） in gastrocnemius and soleus of the rats were measuredusing Western Blotting. Results Compared with group C and R＋F,the maximum strength and speed-strength of group R increased. The endurance of group E increased compared to C,while no significantdifferences were found between group E and E＋F in endurance. The muscle mass,the protein levels offs-myosin and MHC,and the muscle glycogen content of the gastrocemius of group R increased com-pared to group C. However,compared with group E,the above measurements of gastrocnemius and sole-us all decreased except the ss-TnT of soleus. Conclusions The resistance training can enhance themaximum strength and speed-strength by AR,which was related to AR-induced increases of musclemass,fast switch fiber level,MHC level and glycogen content in the gastrocnemius of resistance train-ing rats. But the increase of endurance resulted from endurance training was not likely to be mediatedby AR.