转化生长因子-β对兔胫骨平台骨折愈合的影响及机制

Effect of transforming growth factor-βon fracture healing of tibial plateau in rabbitsa and its mechanism

目的:探讨转化生长因子-β(TGF-β)对兔胫骨平台骨折愈合的影响及机制。方法:75只大白兔随机数字表法分为对照组、骨折模型组和TGF-β组,骨折模型组和TGF-β组兔构建胫骨平台关节塌陷性骨折;对照组仅暴露皮肤,不行胫骨平台骨折。TGF-β组兔经骨折部位注射过表达TGF-β的腺相关病毒1×1011 vg;对照组和骨折模型组经相同部位注射空载腺相关病毒1×1011 vg。治疗4周后,采用X线测定骨折愈合情况;测量3组兔膝关节活性度和肿胀程度变化;采用X线扫描测定3组兔胫骨骨密度;采用马松三色法测定3组兔膝关节韧带纤维化程度;采用三点弯曲法测定胫骨平台生物力学变化。计量资料比较采用方差分析,组间两两比较采用LSD法。结果:TGF-β组大白兔骨折部位X线片评分[(17.09±4.18)分]明显高于骨折模型组[(13.69±3.71)分],差异有统计学意义(t=4.109,P<0.05)。TGF-β组大白兔骨密度(0.48±0.03)明显高于骨折模型组(0.27±0.02),差异有统计学意义(t=3.710,P<0.05)。TGF-β组大白兔膝关节活动度[(118.38±12.43)度]明显高于骨折模型组[(109.22±12.54)度],差异有统计学意义(t=4.011,P<0.05)。TGF-β组大白兔膝关节肿胀程度[(0.20±0.03)cm]明显高于骨折模型组[(0.25±0.03)cm],差异有统计学意义(t=4.381,P<0.05)。TGF-β组大白兔内侧韧带胶原纤维(蓝色)[(37.14±4.79)%]明显低于骨折模型组[(20.15±4.81)%],差异有统计学意义(t=4.193,P<0.05)。TGF-β组大白兔胫骨平台最大载荷、弹性载荷和刚度等三点弯曲指标[(129.75±7.62)N、(85.33±8.01)N、(168.39±9.38)N/mm]明显高于骨折模型组[(71.59±6.09)N、(60.43±6.19)N、(125.41±11.26)N/mm],差异有统计学意义(t=2.761、3.018、2.995,P<0.05)。结论:腺相关病毒介导TGF-β可显著促进胫骨平台骨折愈合,改善膝关节功能,提高胫骨平台的生物力学特性。

Objective To investigate the effect and molecular mechanism on fracture healing of tibial plateau in rats.Methods Totally 75 rabbits were randomly divided into control group,fracture model group and transforming growth factor-β(TGF-β)group by random number table.The tibial plateau joint collapse fracture was constructed in the fracture model group and TGF-βgroup.Rabbits in the control group only exposed skin,and was not subjected to tibial plateau fracture.The rabbits in TGF-βgroup were injected with Adeno associated virus harboring TGF-α(1×1011 vg).The rabbits in the control group and fracture model group were injected with empty adeno-associated virus(1×1011 vg).After 4 weeks of treatment,the fracture healing was measured by X-ray.The activity and swelling degree of knee joint in three groups were measured.The bone mineral density(BMD)of tibia was measured by X-ray scanning.The degree of knee ligament fibrosis was measured by Masson trichrome method.The biomechanical changes of tibial plateau were measured by three-point bending method.Analysis of variance was used to compare the measurement data,and LSD method was used to compare the two groups.Results The X-ray score of fracture site in TGF-βgroup(17.09±4.18)was significantly higher than that in the fracture model group(13.69±3.71,t=4.109,P<0.05).BMD in the TGF-βgroup(0.48±0.03)was significantly higher than that in fracture model group(0.27±0.02,t=3.710,P<0.05).The range of motion of knee joint in TGF-βgroup[(118.38±12.43)degrees]was significantly higher than that in the fracture model group[(109.22±12.54)degrees,t=4.011,P<0.05].The swelling degree of knee joint in TGF-βgroup[(0.20±0.03)cm]was significantly higher than that in the fracture model group[(0.25±0.03)cm,t=4.381,P<0.05].Collagen fibers of medial ligament in TGF-βgroup(blue)[(37.141±79)%]was significantly lower than that in fracture model group[(20.154±81)%,t=4.193,P<0.05].The maximum load,elastic load and stiffness of tibial plateau in the TGF-βgroup[(129.75±7.62)N,(85.33±8.01)N,(168.39±9.38)N/mm]was significantly higher than that in fracture model group[(71.59±6.09)N,(60.43±6.19)N,(125.41±11.26)N/mm,t=2.761,3.018,2.995,P<0.05].Conclusion TGF-βcan significantly promote the fracture healing of tibial plateau,improve the function of knee joint,and improve the biomechanical properties of tibial plateau.