Resveratrol protects osteocytes against oxidative stress in ovariectomized rats through AMPK/JNK1-dependent pathway leading to promotion of autophagy and inhibition of apoptosis.

A large number of studies in recent years indicate that osteocytes are the orchestrators of bone remodeling by regulating both osteoblast and osteoclast activities. Oxidative stress-induced osteocyte apoptosis plays critical roles in the pathological processes of postmenopausal osteoporosis. Resveratrol is a natural polyphenolic compound that ameliorates postmenopausal osteoporosis. However, whether resveratrol regulates osteocyte apoptosis via autophagy remains largely unknown. The effects of resveratrol on regulating osteocyte apoptosis and autophagy were analyzed both in vivo and in vitro. In vitro, cultured MLO-Y4 cells were exposed to HO with or without resveratrol. In vivo, an ovariectomy-induced osteoporosis model was constructed in rats with or without daily intraperitoneal injection of 10 mg/kg body weight resveratrol. It was found that resveratrol attenuated HO-induced apoptosis through activating autophagy in cultured MLO-Y4 cells, which was mediated by the dissociation of Beclin-1/Bcl-2 complex in AMPK/JNK1-dependent pathway, ultimately regulating osteocytes function. Furthermore, it was shown that resveratrol treatment reduced osteocytes oxidative stress, inhibited osteocytes apoptosis and promoted autophagy in ovariectomized rats. Our study suggests that resveratrol protects against oxidative stress by restoring osteocytes autophagy and alleviating apoptosis via AMPK/JNK1 activation, therefore dissociating Bcl-2 from Beclin-1.