Objective: To observe the effects of moxibustion at "Guanyuan" (CV 4) and "Sanyinjiao" (SP 6) on bone morphology, metabolism and ERα of bone marrow mesenchymal stem cells (MSCs) in the ovariectomized rats and explore the underlying mechanism of moxibustion at Guanyuan (CV 4) and Sanyinjiao (SP 6) on the regulation of bone metabolism.
Methods: A total of 60 SD rats were randomized into a normal group (20 rats) and an ovariectomy group (40 rats). In the normal group, no any treatment was provided. In the ovariectomy group, the classical ovariectomy was adopted to set up the osteoporosis model. In the 13th week after ovariectomy, 10 rats were collected from each of the normal group and the ovariectomy group for model identification. After model identification, the ovariectomy group was subdivided into a model group, an estradiol group and a moxibustion group, 10 rats in each one. In the normal group and the model group, the gavage was provided with 2 mL 0.9% sodium chloride solution, once a day. In the estradiol group, the gavage was provided with 17β-estradiol 100 μg/(kg•d), once a day. In the moxibustion group, moxibustion was applied at "Guanyuan" (CV 4) and "Sanyinjiao" (SP 6), 15 min at each acupoint, once a day. The 6 treatments were as one course, with 1 day of interval, 12 courses were required. After 12-week intervention, the dual-energy X-ray was adopted to determine the bone mineral density (BMD) and bone mineral content of the whole body in living condition. After sacrificed, HE staining was adopted to observe femur structure, the enzyme-linked immunosorbent assay was to determine the absorbance of estradiol (E2) and alkaline phosphatase (ALP) in serum and the real-time quantitative PCR method was to determine the mRNA expressions of ERα of MSCs in tibia and femur.
Results: Compared with the model group, BMD was increased obviously in the pelvis and spine in the moxibustion group and the estradiol group (P<0.05, P<0.01). Compared with the model group, the bone mineral content was higher in the rib, pelvis and spine in the moxibustion group and the estradiol group, there was no statistically significant difference (all P>0.05). Compared with the model group, the bone trabeculas were stronger and well connected in the moxibustion group, indicated by HE staining. Compared with the model group, the concentrations of E2 in serum were increased obviously in the estradiol group and the moxibusiton group (both P<0.01), and ALP concentrations reduced obviously in the estradiol group and the moxibustion group (both P<0.001), the mRNA expressions of ERα in MSCs increased in the estradiol group and the moxibustion group (both P<0.001).
Conclusion: Moxibustion at "Guanyuan" (CV 4) and "Sanyinjiao" (SP 6) effectively increases BMD and bone strength in the ovariectomized rats and the mechanism may be related to the improvement of serum E2 concentration, the decrease of serum ALP concentration and the up-regulation of mRNA expression of ERα in MSCs.
Keywords: Point CV 4 (Guanyuan); Point SP 6 (Sanyinjiao); bone mineral density; moxibustion; ovariectomized rats.