[Effect of electroacupuncture of "Guanyuan" (CV 4) on Wnt-ß-catenin signaling in osteoporosis rats].

OBJECTIVE: To observe the effect of electroacupuncture of "Guanyuan" (CV 4) on bone miner density, bone biomechanics, serum osteocalcin (BGP) and alkaline phosphatase (ALP) contents, and femoral osteoblastic Wnt-ß-catenin signaling in postmenopausal osteoporosis (PMOP) rats. METHODS: Forty female SD rats were randomly divided into sham operation (sham), model, EA-CV 4, and EA-non-acupoint (below the costal region) groups (n = 10 in each group). The PMOP model was established by performing an ovariectomy in the rats of the later 3 groups. EA (2 Hz, 1 mA) was applied to CV 4 for 20 min, once daily for one month, with one day's break between every 10 days. After the treatment, serum BGP and ALP contents were detected using ELISA, the right femoral bone miner density and biomechanics (maximum load, breakage load) were measured using a Dual Energy X-Ray Bone Densitometer and a Universal Material Testing Instrument, respectively. The expression levels of Wnt 3 a mRNA, ß-catenin mRNA and the bone-specific factors runt-related transcription factor 2 (Runx 2) mRNA of the femoral bone tissue were determined by real time RT-PCR. RESULTS: HE staining results suggested EA of "Guanyuan" (CV 4) can improve the morphological changes (trabeculae) of osteoporosis in ovariectomized rats. Compared with the control group, femoral maximum load and breakage load, bone density and serum BGP and ALP contents, femoral Wnt 3 a mRNA, ß-catenin and Runx 2 mRNA expression levels, and femoral Wnt 3 a.and ß-catenin immunoactivity were significantly down-regulated in the ovariectomized rats (model group) (P < 0.05). Following EA treatment, all the decreased levels of femoral maximum load and breakage load, bone density and serum BGP and ALP, femoral Wnt 3 a mRNA and protein, ß-catenin mRNA and protein and Runx 2 mRNA expression were obviously reversed in the EA-CV 4 group (P < 0.05) rather than in the non-acupoint group (P > 0.05). CONCLUSION: EA of CV 4 can improve the femoral biomechanics, increase bone density in OVX rats, which are associated to its effects in up-regulating levels of serum BGP and ALP, femoral Wnt 3 a mRNA and protein, ß-catenin mRNA and protein and Runx 2 mRNA expression, suggesting an involment of improved bone metabolism and activation of osteoblastic Wnt-ß-catenin signaling.

[Effect of electroacupuncture of "Mingmen" (GV 4) on bone morphogenetic protein-2 expression in osteoporosis rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) stimulation of "Mingmen" (GV 4) on the bone morphogenetic protein-2 (BMP-2) content and biomechanics in osteoporosis rats so as to explore its mechanism underlying improvement of osteoporosis. METHODS: Fifty female SD rats were randomized into sham operation (sham), model, EA-GV 4, EA-non-acupoint (non-acupoint) and estrogen (medication) groups, with 10 rats in each group. Postmenopausal osteoporosis model was established by removing the rats' bilateral ovaries under anesthesia. EA (2 Hz/15 Hz, 1.0 mA) was applied to "Mingmen" (GV 4) or non-acupoint for 20 min, once daily for 30 times, with one day's interval between every two 10 times. Rats of the medication group were lavaged with Pentanoic Acid Estradiol (25 microg/mL, 2 mL/500 g), once every day (the dosage of estradiol was adjusted according to their body weight) continuously for 1 month. Rats of the model and sham groups experienced the fixing and fastening procedures as the other rats in the EA and medication groups. After intervention, the BMP-2 expression level of the femoral bone tissue, and bone biomechanical values were determined by immunohistochemistry and three-point bending tests, respectively. RESULTS: (1) In comparison with the sham operation group, the femoral biochemical maximum load and fracture load values were significantly decreased in the model group (P < 0.05). While compared with the model group, the biochemical maximum load and fracture load values were obviously increased in the EA-GV 4 and medication groups (P < 0.05), but not in the non-acupoint group (P > 0.05). (2) Compared with the sham group, the femoral BMP-2 expression of model group was significantly decreased (P < 0.05), compared with the model group, the expression of BMP-2 of GV 4 and medication groups significantly increased (P < 0.05). CONCLUSION: EA-GV 4 intervention can improve bone biomechanical changes in osteoporosis rats.