转化生长因子β1在大鼠周围神经再生过程中的作用

目的：探讨转化生长因子β1(TGFβ1)在大鼠周围神经损伤后再生过程中的作用及是否参与了再生中脊髓前角运动神经元碱性成纤维生长因子（bFGF）表达的调节。方法: 将48只成年SD大鼠在右侧坐骨神经压榨损伤术后随机分为TGFβ1组和生理盐水（NS）组。TGFβ1组在坐骨神经压榨损伤近心端注射TGFβ1 50μL(0.1μg/mL)，术后隔日在右侧下肢后群肌内注射TGFβ1 50μL, 对照组同样方法注射等量NS。实验动物分别存活3，7，14和21d后运用免疫组织化学方法检测TGFβ1对脊髓前角运动神经元bFGF蛋白的表达变化。存活21d的实验动物还用半薄切片和Fast Blue逆行荧光示踪方法观察TGFβ1对坐骨神经损伤后远端的再生情况。结果：TGFβ1组脊髓前角bFGF蛋白的表达高于NS组（P<0.05）；损伤远侧端再生轴突数目、直径与髓鞘厚度TGFβ1组均明显好于NS组（P<0.05）； TGFβ1实验组脊髓和背根节内荧光标记细胞数量明显多于NS组（P<0.01）。结论：外源性TGFβ1可以促进周围神经损伤后再生；TGFβ1上调周围神经损伤后脊髓前角运动神经元bFGF的表达。

Effects of transforming growth factor-beta 1 on the peripheral nerve regeneration of rats

OBJECTIVE: To explore the effects of exogenous transforming growth factor-beta 1 (TGFbeta1) on peripheral nerve regeneration after the peripheral nerve injury and if TGFbeta1 regulates the expression of basic fibroblast growth factor (bFGF) in the anterior horn motoneurons of spinal cord during regeneration. METHODS: Forty-eight rats were crushed on the right sciatic nerve and then randomly divided into 2 groups: TGFbeta1 group and NS group. In TGFbeta1 group, TGFbeta1 50 microL (0.1 microg/mL) was injected into the proximal nerve near to the crushed nerve and after the operation the injured leg was injected with equal TGFbeta1 whereas the NS was replaced in the NS group. The rats of each group survived for 3, 7, 14 and 21 days after the lesion. The bFGF expression in the anterior horn motoneurons of spinal cord was detected by immunohistochemistry (IHC). Semi-thin section and Fast Blue retrograde tracing were also performed with the rats surviving for 21 days to observe the regeneration of distal end in the injured right sciatic nerve. RESULTS: The number of bFGF immunoreactive positive motoneurons in TGFbeta1 group was obviously higher than that of the NS group (P < 0.05). In the distal sciatic nerve of the rats treated with TGFbeta1, the number and diameter of regenerating myelinated axons and the thickness of myelinated sheath were more than those of the NS group (P < 0.05). The number of motoneurons in spinal cord and neurons in dorsol root ganglia (DRG) labelled with Fast Blue in the NS group was obviously lower than in the TGFbeta1 group (P < 0.01). CONCLUSION: Exogenous TGFbeta1 plays an important role in promoting the peripheral nerve regeneration; TGFbeta1 up-regulates the bFGF expression in the anterior horn motoneurons of spinal cord during the peripheral nerve regeneration.