动物造模 z-bio 2022-11-23 420

　　OBJECTIVE: To observe the changes of bone mass in tail-suspended rats and the effect and mechanism of simvastatin intervention on this process.

　　Methods: Twenty-four 5-month-old rats were divided into 4 groups, 6 rats in each group: normal control group (CL group), tail suspension group for 6 weeks (UL group), tail suspension group for 3 weeks and weight-bearing for 3 weeks (UL group). +RL group), tail suspension for 3 weeks and weight-bearing plus simvastatin intervention group for 3 weeks (10 mg/kg/d, UL+RL+SIM group); the experiment lasted for 6 weeks, and the rats were sacrificed and the left femur was taken for bone analysis. Density analysis, the left tibia was taken for bone histomorphometric analysis; the right femur was taken to analyze the maximum load and elastic modulus by biomechanical test; the right tibia was taken to prepare tissue homogenate, and RNA and protein were extracted by real-time The expression of collagen type I (Col I) was detected by PCR and western blot.

　　Results: (1) BMD: CL group was significantly higher than the other three groups (P<0.05), UL+RL group and UL+RL+SIM group were significantly higher than UL group (P<0.05); (2) Bone tissue Morphometry: BV/TV: CL group was significantly higher than the other 3 groups (P<0.05), UL+RL group and UL+RL+SIM group were significantly higher than UL group (P<0.05); Tb.N: CL group was significantly higher than the other three groups (P<0.05); Tb.Th: CL group was significantly higher than UL group (P<0.05); Tb.Sp: CL group was significantly lower than the other three groups (P<0.05), UL+ The RL group and UL+RL+SIM group were significantly lower than the UL group (P<0.05). (3) Biomechanical test results: The maximum load and elastic modulus of the CL group were significantly higher than those of the other three groups (P<0.05). (4) Realtime PCR test results: There was no significant difference in the mRNA expression level of ColⅠ among the groups. (5) Western blot: The ColⅠIOD value of the UL group was significantly lower than that of the CL group (P<0.05), and there was no significant difference between the other groups.

　　Conclusion: Tail suspension in rats induces bone loss, microstructure degeneration, decreased mechanical properties, and decreased type I collagen content in the lower extremities, and the above indexes can be partially recovered after reloading, and simvastatin intervention cannot promote this process.