Effects of MiR-21 on Exercises-induced Right Ventricularfibrosis / 中国运动医学杂志

ABSTRACT

Objective To explore the expression level of miR-21 in exercise-induced right ventricular (RV) fibrosis,and to analyze the role of miR-21 in exercise-induced right ventricular fibrosis.Methods Seventy-two male Sprague-Dawley rats were randomly divided into a sedentary (Sed) group,a moderate exercise (ME) group and an intensive exercise (IE) group,each of 24.Rats in the Sed group were free of exercises,while those in ME and IE groups ran an hour on treadmill at 5°and 10° slopes at the speed of 15.2 m/min and 28 m/min respectively for 8 weeks,12 weeks or 16 weeks every day,5days per week.Twenty-four hours after the last training,all rats were sacrificed after blood sampling.The right ventricles were removed,and the collagen volume fraction (CVF) was tested using Sirius red staining,Collagen Ⅰ (Col Ⅰ) content was quantified using Immunofluorescence.The expression level of miR-21 was measured using the reverse transcription-polymerase chain reaction (RT-PCR).Results Af ter 12 weeks (P＜0.05,P＜0.05) and 16 weeks (P＜0.01,P＜0.01) of intensive exercises,the average CVF in the right ventricular was significantly higher than that of Sed and ME rats.Compared to Sed and ME groups,12 weeks (P＜0.01,P＜0.01) and 16 weeks (P＜0.01,P＜0.01) of intensive exercises significantly increased RV collagen Ⅰ content.Compared to the Sed group,the expression of miR-21 in RV increased significantly in the IE group (P＜0.01,P＜0.05 and P＜0.05).After 16-week intensive exercises,the miR 21 expression was positively correlated with the RV Col Ⅰ content.Conclusion The right ventricular fibrosis induced by long-term intensive exercises is associated with increased miR-21 expression level.Therefore,miR-21 is a potent therapeutic target and novel biomarker of the exercise-induced right ventricular fibrosis.