| Objective To observe the effect of astragalus powder (HQS) on the cancellous bone and cortical bone of the tibia in obese rats. Methods Male SD rats (180-200g) were divided into normal group, high fat model group, Lipitor group (2 mg/kg), low-dose HQS group (1.2 g/kg, 10 mL/kg), and high-dose HQS group (2.4 g/kg, 10 mL/kg). Obesity model was established by high fat diet for 7 weeks. HQS was administrated after the modelling for 15 weeks and the rats were then sacrificed. Histomorphometric study of the cancellous bone and cortical bone of the tibia was performed. Results Compared with those in the normal control group, the percentage of trabecular area (Tb.Ar%) and bone trabecular width (Tb.Th) of the tibial cancellous bone in the model group decreased significantly, the percentage of cortical area in the middle section of the tibia (Ct.Ar%) increased significantly, and the percentage of bone marrow cavity area (Ma.Ar%) and the rate of bone formation of the outer membrane(P-BFR/BS) decreased. Compared with those in the model group, Tb.Ar%, Tb.Th, and Tb.Nof the upper segment of the tibia in HQS group increased, the annual formation rate of the new bone (BFR/BV) and Ma.Ar (%) of the middle segment decreased significantly, and P-BFR/BS increased significantly. Conclusion Obesity causes obvious changes in the structure of the tibial cancellous bone in the model rats, showing osteoporosis and increased cortical bone volume. HQS inhibits bone loss of the tibia cancellous bone caused by obesity, and maintains the promoting effect of obesity on the tibial cortical bone of rats. The mechanism may be related to the inhibition of bone resorption, but has no obvious effect on cortical bone. |