Effects Of The Rhodiola On Bcl-2/Bax In Skeletal Muscle Of Mice After The Intensive Training

Rhodiola has various beneficial effects such as anti-fatigue,anti-tumor,anti-depression,enhancing immunity and protecting cardiovascular and cerebrovascular.High intensity exercise for a long time can induce skeletal muscle oxidative damage,free radicals accumulation and DNA damage.Cell apoptosis which is involved in the regulation of the Bcl-2 gene families plays an important role.However,it is not yet fully elucidated that whether rhodiola could regulate Bcl-2/Bax protein expression ratio to prevent or delay the apoptosis of skeletal muscle cells.The present study was aimed to observe the effect of rhodiola supplementation on skeletal muscle cell apoptosis induced by the prolonged intensive exercise.The research will provide scientific basis for rhodiola as nutritional supplements in sports.Methods:24 male KunMing mice about 3 months old were randomly divided into three groups（n=8 for each group）:the control group（C）,the exercise group（E）and the rhodiola +exercise group（RE）.Prepared rhodiola extract suspension according to the dose of 100mg/kg,group RE was daily treated with 0.2ml rhodiola extract suspension,C and E group were treated with equal dose of saline.Group C didn’t exercise and was fed conventionally.E and RE exercised with 0 slope of treadmill for 6 weeks,6 d/w,45 min/day.The first week was adaptive training.The start velocity was 11m/min and increased by 1 m/min/d.From the second week,the velocity increased by 1m/min/w until the 6th weekend.The activity of superoxide dismutase（SOD）,the contents of malondialdehyde（MDA）and Ca²⁺ in both serum and muscle tissue were detected by biochemical kits.The contents of4-hydroxy-2-noneal（4-HNE）,8-Hydroxy-2-deoxyguanosine（8-OHdG）and cytochrome c（Cyt c）in muscle tissue were assayed by enzyme-linked immunosorbent（ELISA）.The Bcl-2/Bax protein ratio of muscle tissue was measured by Western blot.Results:（1）The degree of oxidative damage in each group: compared with E,the activity ofSOD in serum of group RE was significantly increased（P<0.05）,as well as the contents of MDA,4-HNE and 8-OHd G in muscle tissue were also significantly decreased（P<0.01）.In comparison of group C,the contents of MDA in serum and skeletal muscle of group E were significantly increased（P<0.05）,serum SOD activity was significantly reduced（P<0.01）,while the contents of 4-HNE and 8-OHdG in skeletal muscle were significantly increased（P<0.01）.（2）The changes of Ca²⁺and Cyt c contents in muscle tissue of each group: the contents of Ca²⁺and Cyt c in group E were significantly higher than those in group C（P<0.01）;the contents of Ca²⁺ and Cyt c in group RE were significantly lower than those in group E（P<0.05,P<0.01）while significantly higher than that of group C（P<0.01）.（3）The changes of Bcl-2/Bax protein expression in skeletal muscle of each group: the expression ratio of Bcl-2/Bax protein in skeletal muscle of group E was significantly lower than C（P<0.01）;the expression ratio of Bcl-2/Bax protein in skeletal muscle of RE group was significantly higher than that of group E（P <0.01）but lower than C（P <0.01）.Conclusions:（1）Rhodiola supplementation can alleviate the oxidative stress induced by prolonged intensive exercise.（2）Rhodiola supplementation can inhibit the expression of Bax protein and promote the expression of Bcl-2 protein.As a result,Bcl-2/Bax was increased,and the generation of exercise-induced fatigue was delayed.（3）Rhodiola supplementation can restrain the excessive release of Cyt c and decrease the accumulation of Ca²⁺,which inhibits or suspends the apoptosis of skeletal muscle cells.