股骨干髓内循环破坏后临近关节软骨的代谢

Effect of intraosseous circulation system damage on the metabolism of adjacent articular cartilage

背景:骨髓腔内固定物置入治疗股骨干骨折过程中常伴随髓内循环的破坏,部分患者治疗后伴随临近关节软骨的病变,临床多归结于力学因素造成的软骨代谢异常。目的:探讨兔股骨干髓内循环破坏对临近关节软骨代谢的影响。方法:24只新西兰白兔随机分为3组:模型组采用髓腔灌注骨水泥法建立髓内循环破坏模型,对照组暴露髓腔后随即缝合切口,空白组切开过程同前,不暴露髓腔。饲养4周后处死动物,取股骨干膝关节端软骨制备标本。结果与结论:苏木精-伊红染色结果显示:模型组兔关节软骨组织表面出现溃疡、细胞减少、排列紊乱、空泡变性、胶原纤维排列紊乱、断裂,对照组及空白组关节软骨组织表面光滑、平整,细胞及胶原组织排列整齐。RT-PCR检测显示:模型组关节软骨组织骨形态发生蛋白2mRNA、转化生长因子β1mRNA表达低于对照组及空白组,差异有显著性意义。对照组与空白组骨形态发生蛋白2、转化生长因子β1mRNA表达水平差异无显著性意义。结果证实髓内循环破坏能调节骨形态发生蛋白2、转化生长因子β1mRNA表达,影响软骨组织及胶原代谢。

BACKGROUND： The implantation of internal fixators into the medullary cavity is a common method for femoral shaft fractures. However, intraosseous circulation system damage can be usually found in this therapeutic process. Pathological changes of adjacent articular cartilage can be found in some patients after treatment, which may be due to the abnormal cartilage metabolism caused by mechanical factors in clinic. OBJECTIVE： To investigate the effect of intraosseous circulation system damage on the metabolism of adjacent articular cartilage. METHODS： Totally 24 New Zealand white rabbits were randomly divided into model group, control group and blank group. A rabbit model of circulation system damage was established by injection of bone cement into the medullary cavity of rabbits in the model group. In the control group, the medullary cavity of rabbits was exposed, and then the incision was sutured. In the blank group, the bone marrow cavity was not exposed, but the incision progress was the same as the other two groups. After 4 weeks, all rabbits were killed, and articular cartilage tissues from the femoral knee were extracted. RESULTS AND CONCLUSION： Hematoxylin-eosin staining showed that in the model group, ulcer and erosion occurred on the surface of cartilage tissues, and the number of chondrocytes was decreased. Besides, disorganized arrangement and vacuolar degeneration were found. In addition, the arrangement of collagen fibers was disorganized and ruptured. In the control and blank groups, the surface of articular cartilage tissues was smooth, and cells and collagen tissues arranged in order. Reverse transcription-PCR detection indicated that mRNA expression of bone morphogenetic protein-2 and transforming growth factor-β1 in the articular cartilage tissues of the model group was lower than that of the control and blank groups. However, there was no significant difference in the mRNA expression of bone morphogenetic protein-2 and transforming growth factor-β1 between the control and blank groups. These results suggest that intraosseous circulation system damage can regulate the mRNA expression of bone morphogenetic protein-2 and transforming growth factor-β1 and influence the metabolism of articular cartilage tissues and collagens.