Effects of treadmill exercise training on liver fat accumulation and estrogen receptor alpha expression in intact and ovariectomized rats with or without estrogen replacement treatment

Abstract

To explore the mechanism(s) of exercise training on ovariectomized (OVX)-induced liver lipid disorder, we observed effects of treadmill training on liver fat accumulation and ER alpha expression in intact and ovariectomized rats. Sixty female rats were randomly assigned to six groups: Sham sedentary (S-S), Sham exercised (S-EX), ovariectomized sedentary (O-S), ovariectomized exercised (O-EX), ovariectomized injected subcutaneously with 17beta-estradiol (E(2)) (O-E(2)), and ovariectomized treated with E(2) and exercise (O-E(2)-EX). Twelve weeks after intervention, OVX resulted in significantly higher body weight gain, intra-abdominal fat mass, serum levels of total cholesterol (TC), and liver triacylglycerol (TAG) concentrations and ER alpha expression than S-S group, while the relative uterus and liver mass, serum levels of E(2), TAG, and the ratio of high density lipoprotein (HDL) to TC were markedly lower in O-S group. All of these changes were decreased in O-S rats after treatment with E(2) alone with the exception of serum TC and HDL-C levels and liver ER alpha expression. Exercise alone significantly reversed the effect of OVX on serum E(2), the ratio of HDL-C to TC and the liver and intra-abdominal fat accumulation in OVX rats. The addition of E(2) to exercise induced the same uterus and lipid profile as E(2) alone. Moreover, an additive effect of exercise and E(2) was observed on liver ER alpha expression in Sham or OVX rats. In conclusion, treadmill training alone could prevent liver fat accumulation in OVX rats and the regulation of exercise on liver ER alpha expression in both OVX and Sham rats needs the presence of physical estrogen levels.

Exercise Increases Cystathionine-<i>γ</i>-lyase Expression and Decreases the Status of Oxidative Stress in Myocardium of Ovariectomized Rats

“…Some studies have demonstrated that exercise training can increase the level of ERs, which may account for the estrogenic-like effects of exercise. 29) The present study showed that the level of ERα in myocardium was significantly downregulated in OVX rats, and exercise training could restore the ERα expression in OVX rats. This suggests that exercise-induced CSE expression might be due to the upregulation of ERα.…”

Treadmill training prevents bone loss by inhibition of PPARγ expression but not promoting of Runx2 expression in ovariectomized rats

“…Immunohistochemistry was performed as previously reported (Hao et al 2010), but minor reversion was done. In brief, tissue sections were deparaffinized, rehydrated, and rinsed with PBS.…”

“…Western blot was also performed as previously reported (Hao et al 2010). In brief, about 20 lg proteins from each sample were loaded onto 10% SDS-PAGE and transferred onto a PVDF membrane (MILLPORE).…”

Physiological responses during linear periodized training in rats

“…Physical training applied to rats can provide information concerning the metabolic alterations promoted by diseases, diet, surgeries and drugs in relation to homeostasis preservation de Souza et al 2003;Soares de Alencar Mota et al 2008;Gomes et al 2009;Leme et al 2009;Bocalini et al 2010;Botezelli et al 2010;Cambri et al 2010;Hao et al 2010). However, a reduced number of researches are concerned to study different protocols of training for these animals to correlate the intensity, duration, and frequency with the performance Carvalho et al 2005;Laursen et al 2007;Caperuto et al 2009).…”