中文摘要：

目的探讨5-羟色胺受体2A亚型（5-HT2A）在大鼠肝移植术后胆管纤维化中的作用及意义。方法建立再动脉化大鼠原位肝移植模型，分以下4组。对照Ⅰ组和对照Ⅱ组，供肝分别冷保存1和12h后行原位肝移植术；实验组：在对照Ⅱ组基础上，于术后24h起腹腔注射选择性5-HT2A拮抗剂Ketanserin 5 mg·kg^-1·d^-1，直至术后4周观察期结束；假手术组（大鼠仅行开腹和关腹操作，不行肝移植）。术后1d、3d、1周、2周和4周，检测胆道酶系血清碱性磷酸酶、谷氨酰转肽酶、胆红素总量含量以评价胆道功能，采用酶联免疫吸附试验检测肝组织5-HT的含量，以增殖细胞核抗原免疫组织化学染色评价胆管上皮细胞（BEC）的增殖情况。术后4周采用Masson三色染色法观察胆管周围胶原纤维的分布；以α-平滑肌肌动蛋白（α-SMA）作为门管区成纤维细胞（PF）转化为肌纤维母细胞（MF）的标志，进行免疫组织化学染色。术后1、2和4周，采用实时荧光定量聚合酶链反应法检测肝组织内基质金属蛋白酶2（MMP2）和前胶原α1 mRNA的表达。结果与假手术组相比，对照Ⅰ组仅术后1d胆道酶系及5-HT含量升高，术后3d少量BEC增殖，各时点肝组织MMP2和前胶原α1 mRNA的表达无显著增加；术后4周门管区未见或仅见少量胶原纤维及MF。与此相反，对照Ⅱ组和实验组术后1d胆道酶系显著升高，随后下降，术后2周时接近假手术组水平，但术后4周又显著升高，且对照Ⅱ组显著高于实验组，差异有统计学意义（P〈0．05）；两组术后各时点5-HT的含量均显著高于对照Ⅰ组，峰值出现于术后1d，实验组含量有低于对照Ⅱ组的变化趋势，并在术后4周时差异有统计学意义（P〈0．05）。对照Ⅱ组术后3d直至观察期结束可见BEC活跃增殖；术后2周和4周肝组织MMP2和前胶原α1 mRNA的表达显著增加；术后4周门管区可见大量胶?

英文摘要：

Objective To evaluate the role of 5-hydroxy trptamine 2A receptor （5-HT2A） in the pathogenesis of biliary fibrosis after liver transplantation in rats. Method Rats were randomly divided into control group Ⅰ and control group Ⅱ （supplied livers were preserved for 1 or 12 h）, ketanserin group （recipients of control group Ⅱ were intraperitoneally injected with ketanserin 24 h postoperatively at the. dosage of 5 nag· kg^-1 · day^-1 ）, and sham group （rats were subjected to transverse laparotomy and closure without manipulation of the liver）. During 4-week observation period, serum biliary enzymes, 5-HT content in the liver, the expression of fibrosis-related genes, cholangiocytes proliferation and biliary fibrosis were evaluated. Result Compared with the sham group, the serum ALP, GGT, TBil and 5-HT contents in the liver homogenate were increased on the postoperative day 1 （POD1） and then restored to the normal level. There was slight proliferation of bile duct epithelial cells on POD3 in the control group Ⅰ , with fewer collagen fibers and α-sooth muscle actin （α-SMA）-positive myofibroblasts in the portal area. The expression of matrix metalloproteinase-2 （MMP-2） and procollagen α1-mRNA in graft livers was not significantly increased in the control group Ⅰ . To the contrast, the control group Ⅱ demonstrated high levels of serotonin in the liver homogenate and enhanced serum biliary enzymes. Active cholangiocytes proliferation was triggered on POD3 and remained higher than in the control group Ⅰ and the sham group. The control group Ⅱ showed a large number of α-SMA-positive myofibroblasts and collegan fibers at the postoperative week 4. In parallel, the major profibrogenic transcripts MMP2 and procollagen α1 were significantly increased at 2nd, and 4th week postoperation in the control group Ⅱ. Importantly, we also found that ketanserin relieved the signs of biliary fibrosis at 4th week postoperation in 5-HT2A group by the demonstration of reduced collagen fibers a