Effect of moxibustion of "Ganshu"(BL18) and "Shenshu" (BL23) on musculoskeletal interaction in osteoporosis rats

Abstract

To observe the effect of moxibustion of "Ganshu" (BL18)and "Shenshu" (BL23) on bone mineral density (BMD), biomechanics, bone metabolism and musculoskeletal morphology of osteoporosis (OP) rats, so as to explore its mechanism underlying treatment of OP via bone-muscle interaction. Thirty-two female SD rats were randomly divided into sham operation, OP model, moxibustion and medication (nilestriol) groups, with 8 rats in each group. For rats of the sham operation group, a small amount of fat around the ovaries was removed, and those of the other 3 groups received removal of bila-teral ovaries for establishing OP model. Moxibustion was applied to bilateral BL18 and BL23 for 30 min, once every other day, 3 times a week for 12 weeks. Rats of the medication group received gavage of nilestriol (1 mg/kg) once a week for 12 weeks.After the interventions, a dual-energy absorptiometry was used to determine the BMD and bone mineral content of the rats' right femur and the fourth lumbar vertebrae under anesthesia, and three-point bending test used to detect the biomechanical properties (including load, displacement, stiffness) of the right femur. The levels of serum type I collagen C-terminal peptide (CTX-I), acid-resis-tant tartrate phosphatase (TRACP) and estradiol (E2) were determined using enzyme-linked immunosorbent assay, and histopathological changes of the left femur and the quadriceps observed after hematoxylin-eosin (H.E.) staining. Compared with the sham operation group, the BMD and bone mineral contents of the right femur and the fourth lumbar vertebra, the load and stiffness of the right femur, and concentration of serum E2 were significantly decreased (P<0.01, P<0.05), and the displacement of the right femur, and concentrations of serum CTX-Ⅰ and TRACP notably increased in the model group (P<0.01). After the interventions, the decreased levels of BMD and bone mineral contents, the load and stiffness and concentration of serum E2, and the increased levels of the displacement, and concentrations of serum CTX-Ⅰ and TRACP were all reversed by both moxibustion (except the bone mineral content of the fourth lumbar vertebra) and medication (P<0.01,P<0.05). No signi-ficant differences were found between moxibustion and medication in up-regulating the levels of BMD and bone mineral contents, the load and stiffness (except serum E2) and down-regulating the levels of the displacement, and concentrations of serum CTX-Ⅰ and TRACP (P>0.05). H.E. staining revealed that rats in the sham operation group showed mild thinness of the bone cortex, uneven thickness of trabecular bone, with distortion, fracture and osteoporosis of the left femur, and different size of rhabdomyocytes in the right quadriceps femoris muscle, with obvious proliferation of interstitial fibrous tissue and inflammatory cell infiltration, which were relatively and clearly milder in both moxibustion and medication groups. Moxibustion of BL18 and BL23 can increase the BMD and bone mineral content, improve biomechanical performance, adjust bone metabolism, and mitigate bone and the attached muscle histopathological changes in OP rats, suggesting that modulating interaction between bones and muscles is probably one of the ideas in the treatment of OP.