Effect of resveratrol on heart and striated muscles in heavy exercised rats effect on endoplasmic reticulum stress

Aim: Heavy exercise may cause endoplasmic reticulum stress. The aim of this thesis was to investigate the efficacy of resveratrol on ER stress, one of the mechanisms of damage in striated and myocardial muscle caused by heavy exercise. Material and Method: Rats were divided into three groups as Control (n=10), High intensive Exercise (n=10) (H-Ex), High intensive Exercise + Resveratrol (n=10) (H-Ex+RES). Rats in the H-Ex and H-Ex+RES groups were made to swim for 10 weeks, with swimming times increasing by 10 min every 2 weeks. Rats in H-Ex and H-Ex+RES groups were loaded with 5% of their body weight in the first week and their swimming time was increased by 1% every 2 weeks. Resveratrol (10 mg/kg/day) was given to H-Ex+RES group in the last 4 weeks of the study. Protein levels of ER stress markers GRP78, XBP1, ATF4 were measured in left ventricle and gastrocnemius muscle by Western blotting. Data were analyzed by appropriate statistical methods. Results: GRP78 and ATF4 levels increased in both left ventricular and gastrocnemius muscle in H-Ex group (p<0.05). In the H-Ex, XBP1 levels decreased in the left ventricle and increased in gastrocnemius muscle (p<0.05). In the H-Ex+RES group, resveratrol inhibited the elevation of GRP78 and ATF4 in both tissues but caused a lower level of XBP1 in the left ventricle compared to both control and H-Ex groups (p<0.05). Conclusion: While intense exercise increased ER stress in both cardiac and skeletal muscle, resveratrol was found to be highly beneficial in reducing ER stress. Key Words: Activating Transcription Factor 4, Endoplasmic Reticulum Stress, Glucose Regulating Protein 78, Resveratrol, Swimming exercise, X-box Binding Protein 1