| In recent years, the research on the endocrine function of adipose tissue, the discovery of leptin and cloning had made bone metabolism research get quite breakthrough progress. Leptin regulating bone metabolism mechanism is complex, involving the nerve, body fluids, and many other comprehensive factors. Especially the leptin regulate sympathetic nerve (SNS) caused widespread concern in recent years.The leptin can stimulate the beta-2receptor in the bone through the sympathetic nerve.That phenomenon had attracted attention of some scholars, and the leptin is expected to become the new target to prevent the osteoporosis. Modern research has shown that, the loss of bone mass of menopausal women associate with not only estrogen reduce, but also the increased activity of sympathetic nerve. In view of the above theory, by using the classical beta-blocker propranolol for anti-osteoporosis role research, this study attempts to observe the different dose of propranolol influence bone metabolism of osteoporosis rats. The subjects of this study were sixty healthy female unmated SD rats, weighed for (200±20)g, wich are randomly divided into5groups:(1) the blank group (OVX);(2) the low dose group (OVXL)(give1mg/kg. D)(3) medium dose group (OVXM)(give5mg/kg. D)(4) high dose group (OVXH)(and mg/kg. D)(5) SHAM group (Sham). Before going to do ovarian surgery and after the ovarian respectively in4,8,12,18,22weeks, we used dual energy X-ray to detect the rat whole body of the rats. we used serum enzyme linked immune method to detect bone metabolic markers.After12weeks,we assure that the osteoporosis model was success, and giving each group rats corresponding drugs, among them, the OVX group and SHAM group were given physiological saline, and the OVXL,OVXM and OVXH group were given different dose propranolol which were dissolved in the same dose of physiological saline, and then this drug was given the rats to lavage. After treatment10weeks of this treatment, each group rats were put to death. We take the L5, left femur, not decalcified section to analyze bone form metrology change. We take the right femur to detect the biomechanical changes.Results show that afer22weeks of the ovarian, SHAM group rats weight was significantly lower than the other group rats.For the OVXL, OVXM, OVXH, OVX rats, their whole-body of BMD and BMC, was significantly lower than the SHAM group, but OVXL group and SHAM group of BMD and BMC data showed that there was statistical significance. But OVXL group of BMD and BMC data was lower than SHAMgroup,and there had statistical significance.OVXH and OVX group of BMD and BMC datas suggest that there was no significant statistical significance.The bone loss of the rats was most obvious in initial4weeks after ovarian. After the initial4weeks,the bone loss was slow down.Compared with before ovarian,the rats of BMD decrease about8%at initial4weeks. Compared with surgery before ovarian,the rats of BMD decreased about13%at12th week.Bone form metrology and bone metabolic markers prompted osteoporosis caused by ovarian were a high conversion type. Biomechanical testing showed that low doses of propranolol for bone had most obvious improvement.This improvement for performance was shown that OVXL group compared with other groups rats were statistically significant (P<0.05), and this group is lower than SHAM but higher than other groups.High dose propranolol was for femoral biomechanics had no obvious improvement action, and this phenomenon was shown that OVXH group and OVX groups femoral biomechanical testing had no statistical significance.Propranolol can be reversed by postmenopausal osteoporosis,and it can also improve bone mineral density and bone mineralization rate. Low dose of propranolol had obvious improvement effect for four parts of bone mineralization rate, but was not obvious for axial skeleton effect. High levels of propranolol has certain improvement effect for axial skeleton, but was not obvious for four parts to improve effect. |
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