两种加压应力对骨折局部TGF-β和TGF—β_1 mRNA表达的影响

Effect of different compressive stress on temporal expression of TGF-β and TGF-β_1 mRNA at fracture site

目的:探讨两种加压应力对骨折愈合过程中TGF-β和TGF-β_1mRNA表达的影响。方法:建立兔双侧肱骨骨折天鹅型记忆接骨器(SMC)和动力加压接骨板(DCP)内固定模型,术后1、3、7、14、21、28和56d各处死5只兔,分别应用免疫组化和原位杂交技术,结合图像分析系统计算骨折局部TGF-β和TGF-β_1mRNA的染色阳性指数。结果:术后7～28d,SMC组TGF-β含量明显高于DCP组(P<0.05,P<0.01);术后7～28d,SMC组TGF-β_1mRNA明显含量高于DCP组(P<0.05,P<0.01)。结论:SMC所产生的持续动态加压应力环境较DCP所产生的静态加压应力环境更能促进骨折端TGF-β和TGF-β_1mRNA的表达。TGF-β_1可能在加压应力的传递过程中起到重要作用。

Objective:To explore the effect of two different compressive stress on expression of transforming growth factors(TGF-β) and TGF-β_1 mRNA at fracture site. Method: Humeral fracture in 35 New Zealand rabbits were internally fixed by swanlike memory compressive connector(SMC) or dynamic compression plate (DCP)respectively. Each five experimental animals were sacrified at different time (1,3,7,14,21,28,56 days postoperatively). The expression of TGF-β was detected by immunohistochemistry and TGF-β_1 mRNA by in situ hybridization techniques. The content of TGF-β and TGF-β_1 mRNA were measured using computed image analysis system. Result:The expression of TGF-β in group SMC was significantly higher than that in group DCP at 7～28d (P<0.05,P<0.01). The expression of TGF-β_1 mRNA in group SMC was also significantly stronger than that in group DCP at 7～28d(P<0.05, P<0.01). Conclusion:Compared with the static compressive stress produced by DCP, the sustained dynamic memory compressive stress produced by SMC may enhance the expression of TGF-β and TGF-β_1 mRNA at fracture sites, thus promote fracture healing. TGF-β_1 may play an important role in transducing compressive mechanical stimulation to tissue at fracture site.