稳定或不稳定骨折愈合与巨噬细胞及骨形态发生蛋白2的关系

目的:研究稳定或不稳定骨折愈合过程中巨噬细胞和骨形态发生蛋白2 (BMP - 2 )的分布与作用,探讨不同力学条件下骨折愈合的细胞与分子机理。方法:60只成年雄性SD大鼠随机分为固定组和非固定组,每组30只。麻醉后,采用三点弯曲法造成右胫骨中段闭合性骨折模型。固定组行髓内钉固定,非固定组不做任何固定。处理后不同时间取材行组织学及免疫组化检查和分析,测定骨折愈合过程中骨折断端巨噬细胞分化抗原(CD68)和BMP - 2阳性细胞计数和浓度值变化。结果:两组CD68表达第1天均为阳性,第2天下降,第4天达到高峰,以后下降,第8天固定组表达消失,第1 0天非固定组表达也消失。固定组CD68计数均高于非固定组,差异有显著性(P <0 .0 5)。两组BMP - 2表达第4天均存在,第8天达高峰,以后下降,第2 8天仍有表达。其中第4、5、8天固定组BMP - 2计数均高于非固定组,差异有显著性(P <0. 0 5) ,第1 4、2 1、2 8天非固定组BMP - 2计数均高于固定组,差异有显著性(P <0.0 5)。结论:骨折处力学条件能影响胞外基质分子的表达和巨噬细胞的迁入,并改变参与骨折愈合的细胞间的相互作用。巨噬细胞在软组织和骨愈合中都是一个重要因素。BMP - 2在骨折愈合和骨改建中起重要作用

Relationship between macrophage and bone morphogenetic protein 2 in stabilized or non-stabilized fractures healing.

Objective:To study the distribution and effect of macrophages and bone morphogenetic protein 2 (BMP-2) during fracture healing in stabilized and non-stabilized fractures and to probe the cellular and molecular mechanism.Methods:Sixty mature male SD(Sprangue-Dawley) rats were randomly divided into stabilized and non-stabilized fracture groups.Closed unstable transverse mid-diaphyseal fractures of the right tibia were created in three-point bending in the anesthetized SD rats.One-half of the fractures were left non-stabilized.The other half of the fractures were stabilized in intramedullary fixation.The histoligical examination(HE staining, mason staining)and immunohistochengistry(SABC method)were done to investigate the expression of CD 68/BMP2 in different period of fracture healing.Results:Immunohistochengical identification showed which the signals for CD68 were positive on the first day,On the 4th day,the signals rose to their maxinum.Whereas in the steel-nailed fractures no signals for CD68 were visible on the 8th day,definite signals were still apparent in the non-stabilized group.On the 10th day signals for CD68 were no longer detectable even in the non- stabilized group.The average numbers and concertration value of CD68 at fracture site was slightly greater in the stabilized group,and has significance difference(P<0.05).On 4th day the signals for BMP2 were visible at fracture-healing site.On the 8th day the signals rese to their maximum.Subsequently the signals diminished in both groups.Whereas on the 28th day the signals for BMP2 were still apparent in the both groups.The average numbers and concertration values of BMP2 at fracture site was slightly greater in the stabile group on the 4?5 and 8th day respectively and in the non-stabilized group on the 14?21 and 28th day respectively,and the difference has statistical significance(P<0.05).Conclusions:The expression of extracellular matrix molecuoe and the immigration of macrophage can be influencd by the mechanical condition at the fracture gap and that this will modify the interplay of the cells involved in fracture healing.Macrophage are an important factor not only in soft tissue healing but also in bone healing.BMP2 play an important role in the form of bone regeneration and reconstruction.