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.

Chinese abstract

运动训练已被视为治疗去卵巢（OVX）引起的功能障碍的一个非药物方法。在这项研究中，我们观察慢性运动是否对去卵巢大鼠心肌中尿皮质激素及促肾上腺皮质激素释放激素受体2型（CRHR2）的表达有影响。在麻醉下进行双侧卵巢切除或假手术。两组又各分成两个亚组，其中一组进行活动平板训练8周，另一组则不进行训练。结果发现：卵巢切除及运动均不影响心肌中UCN、UCN2和UCN3的mRNA水平。卵巢切除引起心肌中CRHR2下调。运动训练逆转卵巢切除导致的CRHR2减少，但对假手术组大鼠CRHR2的水平没有影响。卵巢切除可导致心肌中雌激素受体α(ERα)的表达降低，但可通过锻炼恢复。此外，运动训练能逆转卵巢切除所导致的心肌中特异蛋白-1(Sp-1)的降调节。心肌中CRHR2的表达水平与SP-1和ERα的水平相关。这些结果表明：运动训练可以恢复去卵巢大鼠心肌CRHR2的水平，而CRHR2的表达水平与SP-1和ERα的水平相关。

• Corticotropin-releasing hormone receptor type 2
• estrogens
• exercise training
• myocardium
• urocortin

Declaration of interest

The authors report no declarations of interest. This work is supported by National Natural Science Foundation of China (No. 31000516 and No.31371197), Key Laboratory of Exercise and Health Sciences of Ministry of Education, Shanghai University of Sport.