Reduced expression of CRHR2 and Sp-1 in myocardium of ovariectomized rats is improved by exercise training

Abstract

Exercise training has been looked on as a non-pharmacologic approach to treating ovariectomy (OVX)-induced dysfunctions. In this study, we investigated whether chronic exercise impacts on expression of urocortins (UCNs) and corticotropin-releasing hormone receptor type 2 (CRHR2) in myocardium of OVX rats. Bilateral OVX or sham-operation was performed under anesthesia. Both groups were then divided into two subgroups, with or without treadmill training for 8 weeks. It was found that OVX as well as exercise did not affect the mRNA levels of UCN, UCN2 and UCN3 in myocardium. OVX caused down-regulation of CRHR2 in myocardium. Exercise training reversed the OVX-induced reduction of CRHR2, but had no influence on CRHR2 level in sham rats. OVX resulted in a decrease in estrogen receptor α (ERα) expression in myocardium, which was restored by exercise. Moreover, exercise training also reversed OVX-induced down-regulation of specific protein-1 (Sp-1) expression in myocardium. CRHR2 expression level correlated with Sp-1 and ERα level in myocardium. These results indicate that exercise training can restore the CRHR2 level in myocardium of OVX rats, which is associated with ERα and Sp-1 expression.