Electroacupuncture stimulation at CV4 prevents ovariectomy-induced osteoporosis in rats via Wnt-β-catenin signaling

The present study aimed to investigate the effect of electroacupuncture stimulation at CV4 (also termed Guanyuan) on femoral osteocalcin also termed bone gla protein (BGP), alkaline phosphatase (ALP), bone mineral density (BMD) and biomechanics, as well as the Wnt-β-catenin signaling pathway in rats with postmenopausal osteoporosis. Female Sprague-Dawley rats (4.5-months old) were randomly divided into sham, Ovx, CV4 and mock groups (n=10/group). With the exception of those in the sham group, the rats were ovariectomized to induce postmenopausal osteoporosis. The rats in the CV4 and mock groups were given electroacupuncture at CV4 and non-acupoint, respectively. The rats in the Ovx model and sham groups underwent identical fixing procedures, but did not undergo electroacupuncture. Following treatment, hematoxylin and eosin staining was used to observe morphological changes in the left femoral trabecular bone, and a three-point-bending test was used to analyze femur biomechanics and determine the BMD. In addition, an enzyme-linked immunosorbent assay was used to measure the serum levels of ALP/BGP and reverse transcription-quantitative polymerase chain reaction was used detect the expression levels of Wnt3a, β-catenin and Runx2. In the present study, it was demonstrated that electroacupuncture at CV4 significantly improved the osteoporotic morphological changes that occurred in the ovariectomized rats, increased serum ALP and BGP levels, enhanced the maximum and fracture loads, increased BMD (P<0.01), and activated the Wnt-β-catenin signaling pathway. These findings demonstrated that electroacupuncture stimulation at CV4 affected bone formation and promoted bone metabolism in rats with postmenopausal osteoporosis, possibly by activating the Wnt-β-catenin signaling pathway.