牵拉损伤对大鼠坐骨神经影响的实验研究

目的探讨大鼠坐骨神经牵拉伤后MRI变化以及损伤过程中转化生长因子β1(transforming growth factorβ1,TGF-β1)的表达和Ⅰ、Ⅲ型胶原蛋白(COL-Ⅰ、Ⅲ)含量的变化。方法将50只成年雄性SD大鼠随机分为对照组(仅暴露坐骨神经)和牵拉组(大鼠右侧后腿坐骨神经牵拉伤),分别于术后3d,2、4、6、8周,随机取两组大鼠各5只,切取牵拉段神经行MRI、组织形态学、免疫组织化学的观察及反转录酶-聚合酶链式反应(RT-PCR)、Western Blot定量测定TGF-β1的表达和COL-Ⅰ、Ⅲ含量。结果牵拉损伤后MRI表现为神经增粗,T1、T2时间延长;牵拉组大鼠坐骨神经TGF-β1的表达和COL-Ⅰ、Ⅲ含量明显高于对照组,两者差异有统计学意义(P0.05)。结论坐骨神经牵拉损伤后,周围神经发生纤维化病变,COL-Ⅰ、Ⅲ含量显著增加,TGF-β1表达有显著差异,提示TGF-β1在周围神经纤维化过程中具有一定的作用。

Experimental research of effects of traction injury on the rat sciatic nerve

Objective To investigate the change of MRI , transforming growth factor β1(TGF-β1) and col-lagen type Ⅰ,Ⅲ( COL-Ⅰ,Ⅲ) after sciatic nerve traction injury .Methods Fifty adult male SD rats were ran-domly divided into group A and B .In group A ( the control group ) the sciatic nerve of rats was exposed only .In group B( the traction injury group ) the sciatic nerve of rats was tracted by smooth forceps to produce traction injury . Electron microscopy , immunochemistry , RT-PCR and Western Blot were performed to observe the morphological changes of the tracted nerve tissue and to determine the level of TGF-β1,COL-Ⅰand COL-Ⅲat 3 days and 2,4,6, 8 weeks after the surgery ,respectively .Results The injured nerve was characterized as thickened in size and in-creased T1 and T2 relaxation time.The expression of TGF-β1 in the traction injury group was significantly higher than that of the control group (P<0.05).In the meanwhile,the contents of COL-Ⅰ,COL-Ⅲwere positively corre-lated in a certain period(P<0.05).Conclusion Peripheral nerve fibrosis can be caused by nerve traction injury which induces increased expression of COL-Ⅰ,COL-Ⅲin the nerve .TGF-β1 is significantly higher than that of the control group ,which suggests that TGF-β1 plays an important role in the process of neural injury and fibrosis .