中文摘要：

目的观察γ干扰素（IFN-γ）局部注射对小鼠骨骼肌钝挫伤后纤维化以及转化生长因子-β（TGF—B）-Smad信号通路表达的影响。方法将30只成年雌性C57bl小鼠随机分为正常组（A组）、磷酸盐缓冲液（PBS）注射组（B组）和hIFN-γ注射组（C组），每组10只。B、C组采用50g钢球于30cm高度下砸的方法造成双侧腓肠肌钝挫伤，分别于伤后1、2、3周局部皮下注射0．1ml PBS或hIFN-γ,A组不行任何处理；4周后取双侧腓肠肌检测。以Masson染色后计算胶原纤维面积评估骨骼肌纤维化程度，Western blot检测TGF-β1、Smad2、Smad3、Smad4、Smad7蛋白表达水平。结果Masson染色显示B组胶原面积最大为（14074．0±15．2）μm^2（P〈0．05），C组为（4019．0±13．4）μm^2高于A组（1741．0±10．1）μm^2（P〈0．05）；TGF-β1在B、C组表达增高（P〈0．05），但两组之间表达差异无统计学意义（P〉0．05）；3组间Smad4、7的表达差异无统计学意义（P〉0．05）；Smad2、3及其磷酸化蛋白在B、C组表达升高（P〈0．05），其中磷酸化的Smad2、3在C组较B组表达明显降低（P〈0．05）。结论局部注射hIFN-γ,未发现影响TGF-β1的表达，但能够有效降低Smad2、3磷酸化蛋白的表达，可能是其抑制损伤骨骼肌纤维化的作用机制。

英文摘要：

Objective To observe the imquence of local injection of human interferon γ （hIFN-γ） on the fibrosis and transforming growth factor-β1 （ TGF-β1 ） -Smad signal pathway in the skeletal muscle following acute contusion. Methods Thirty female C57bl mice were randomly divided into 3 groups as A, B and C. The mice in groups B and C were injured by heavy hit of a 50 g ball from 30 cm height to establish gastrocnenfius contusion models, and then subcutaneously injected with 0. 1 ml PBS and hIFN-γ respectively. No interference was given to group A. All mice were sacrificed 4 weeks later to harvest the gastrocnemius. Fibrosis was estimated by calculating collagen areas on masson staining section. Expression of the proteins as TGF-β1, Smad2, Smad3, Smad4 and Smad7 was detected by Western blotting. Results The collagen area on masson staining section of group B was the greatest as （ 14 074. 0 ± 15.2 ） μm^2, and that in group C was （4019.0±13.4） μm^2, greater than that in group A （1741.0±10.1） μm^2（P〈 0. 05 ）. The level of TGF-β1 was increased in both groups B and C, but without statistically significant difference between them （ P 〉 0. 05 ）. No significant difference was found in Smad4 and Snlad7 protein expression among three groups （P 〉 0. 05）. Total Smad2 and Smad3 were increased in groups B and C but without significant difference （ P 〉 0. 05 ）. Phosphorylated Smad2/3 level was also increased in both groups B and C, and that was lower in group C （ P 〈 0. 05 ）. Conclusion Without influence on the expression of TGF-β1, local injection of hIFN-γ could reduce the phosphmylation of Smad2/3 significantly, which probably contributed to the suppression of fibrosis within injured skeletal thuscle.