胆道闭锁肝纤维化病变中平滑肌肌动蛋白表达的研究

A study of α-SMA expresson in the fibrous cone in biliary atresia

目的本研究通过检测平滑肌肌动蛋白（α-SMA）在胆道闭锁（BA）肝组织和肝外胆系的表达，探讨肝纤维化过程与临床预后的关系。方法采用免疫组化染色方法对2005年7月至2006年5月本院21例BA肝组织、肝门纤维块进行CD68和α-SMA染色；对照组为5例胆汁淤积和10例胆总管囊肿。选用LEICA-DM研究级生物显微镜，QWIN软件环境下测量抗体阳性细胞面积百分比和平均光密度，随访19例BA术后3个月直接胆红素下降比率。同时对21例BA肝组织纤维化分级，并与α-SMA表达量进行相关分析。结果α-SMA在BA肝纤维块高度表达于胆管上皮、胆管周围的胶原纤维；α-SMA阳性表达量和表达强度明显高于对照组，其表达量与表达强度呈线性正相关（r=0．549，P=0．022）；CD68在BA肝组织表达较对照组明显增强，但肝门纤维块鲜有表达。α-SMA表达量与肝脏纤维化分级呈正相关（P=0．02）；α-SMA阳性表达面积百分比与术后3个月直接胆红素下降率呈负相关（r=-0．653，P=0．029），但肝组织CD68表达与α-SMA阳性表达相关性不明显（r=0．444，P=0．057）。结论α-SMA的表达可能是肝脏纤维化的早期标志，SMA的阳性表达量与术后3个月胆红素消退呈显著负相关，预示BA肝内外胆管系统纤维化，乃至肝硬化，提示可能临床预后不佳。

Objective The aim of this study was to evaluate the α-SMA expression in liver and porta hepatis in biliary atresia patients. Methods From Sept 2005 to May 2006, 21 patients with biliary atresia underwent Kasai procedure. Liver biopsy and the fibrous cone of porta hepatis were studied. 5 cases of cholestasis Syndrome and 10 cases of choledochal cyst were used as the control group. Immunohistochemistry of α-SMA and CD68 in BA＇s liver and porta hepatic was performed. Leica DM microscope was used to acquire the image of immunohistochemistry. Qwin software was used for morphometric study. Semi-quantitative 3 grade staging system was employed to estimate the liver fibrosis. The densities of CD68 in BA＇s liver and the level of direct bilirubin were assessed in relation to the α- SMA expression. SPSS software was used for statistical analysis. Results （1） α-SMA was highly expressed in the epithelial cells and periductular collagen fiber. The expression in BA was stronger than that of the control group （r= 0. 549,P = 0. 022）. （2） The amount of α-SMA in BA positively correlα- ted with the liver fibrosis score（P = 0. 02）. （3） The proportions of α-SMA in liver of BA negatively related with the reduction rate of direct bilirubin 3 months postoperatively. （r = - 0. 653,P = 0. 029）. （4） The correlation between the α-SMA and CD68 expression was not significantly （r = 0. 444, P = 0. 057）. Conclusions In this study, expression of α-SMA in liver of BA patient is higher than that of the control group. This indicates that the liver fibrogenesis started early in BA. α-SMA expressing negatively correlated with the reduction of direct bilirubin 3 months postoperatively, suggesting fibrosis, or cirrhosis, in the entire biliary system.