抗组胺治疗对实验性肝炎大鼠肥大细胞浸润及c-Kit和SCF表达的影响

 目的：研究c-Kit和干细胞因子（SCF）在实验性肝炎大鼠肝脏组织的表达及抗组胺治疗后的变化。方法：取Wistar大鼠30只，随机分为3组：正常对照组（NC）、慢性肝炎组（CH）和抗组胺治疗组（AH）。CH组采用复合因素造模（用40%四氯化碳油溶液皮下注射，同时辅以低蛋白、低胆碱、高脂肪、高醇饮食），AH组在CH的基础上给予抗组胺治疗（酮替芬）。4周末处死动物，取血分别检测血浆类胰蛋白酶（TS）和组胺（HA）水平，同时观察肝脏组织学变化及肥大细胞形态改变。应用免疫组织化学方法观察肝脏c-Kit和SCF的表达。用RT-PCR方法观察肝组织c-Kit和SCF mRNA的表达水平。结果：（1）与正常对照组比较，慢性肝炎组TS、血和肝组织HA水平均有明显升高（P<0.05），经抗组胺治疗后，TS、血和肝组织HA水平均明显降低（P<0.05）。（2）光镜下，慢性肝炎组有脂肪变性和纤维化形成，而治疗组肝损伤明显减轻；甲苯胺蓝染色可见慢性肝炎组肝脏血管周围及纤维间隔内大量正在脱颗粒和已经脱颗粒的充满紫色颗粒的肥大细胞。治疗组仅见胞浆中充有少量紫色颗粒。定量统计发现，慢性肝炎组肥大细胞数目较正常对照组明显升高（P<0.05），抗组胺治疗后，肥大细胞数目明显减少（P<0.05）。（3）RT-PCR结果显示抗组胺治疗可以下调c-Kit和SCF mRNA表达水平（P<0.05）。免疫组织化学染色显示慢性肝炎组高表达c-Kit和SCF（均P<0.05），抗组胺治疗可以下调二者的表达（P<0.05），而且二者的表达均与HA水平呈明显正相关。结论：肥大细胞参与了实验性肝炎的炎症过程。酮替芬可以通过下调肥大细胞膜受体c-Kit及其配体SCF的表达使肥大细胞脱颗粒减少，组胺释放减少，从而减轻肝脏炎症。

Effects of antihistamine treatment on mast cell infiltration and c-Kit and SCF expression in liver tissues of rats with experimental hepatitis

AIM：To study the infiltration of mast cells and the expression of c-Kit and stem cell factor (SCF) in liver tissues of rats with experimental hepatitis and their changes after antihistamine (AH) treatment. METHODS：Thirty Wistar rats were divided into 3 groups at random: normal control (NC) group, chronic hepatitis (CH) group and AH group. The rat model of CH was established by composite factors (subcutaneous injection of carbon tetrachloride, accompanied by a diet containing high cholesterol, high alcohol, low protein and low choline). The rats in AH group were treated with ketotifen based on CH. At the end of the 4th week, blood samples were taken to determine plasma tryptase (TS) and histamine (HA) levels. Liver tissues were taken to detect HA content, observe the histological changes with HE staining and count the number of mast cells with toluidine blue (TB) staining. The mRNA and protein expression of c-Kit and SCF in liver tissues was detected by RT-PCR and immunohistochemistry. RESULTS：(1) The plasma TS and HA levels and liver HA content in CH group were significantly increased compared with NC group (P<0.05), while those in AH group were obviously decreased compared with CH group (P<0.05). (2) Fatty degeneration and fibrosis were observed in CH group under light microscope, but the hepatic injury was obviously attenuated in AH group. TB staining showed there were many degranulating and degranulated mast cells filled with purple granules around liver blood vessels and in fiber interval in CH group, and there were few purple granules in the cytoplasm of mast cells in AH group. The number of mast cells in CH group was increased compared with NC group (P<0.05), and that in AH group was reduced compared with CH group (P<0.05). (3) The results of RT-PCR showed that AH down-regulated the expression of c-Kit and SCF mRNA (P<0.05). The expression of c-Kit and SCF proteins in liver tissues increased in CH rats (P<0.05 vs NC group), decreased after AH treatment (P<0.05 vs CH group) and was positively correlated with liver HA content (P<0.05).  CONCLUSION：These data suggest that an inflammatory pathway mediated by mast cell activation is involved in experimental hepatitis. Ketotifen can reduce mast cell degranulation by down-regulating the expression of mast cell membrane receptor c-Kit and its ligand SCF, thereby attenuating the liver inflammation.