Th17细胞因子及炎症趋化因子在日本血吸虫感染小鼠肝脏中的表达

Expression of the cytokine and chemokine associated with Th17 cell in the liver of mouse infected with Schistosoma japonicum

目的观察日本血吸虫感染C57BL/6小鼠肝脏Th17细胞因子及其相关炎症趋化因子动态变化和肝脏虫卵肉芽肿病变,探讨其在日本血吸虫虫卵肉芽肿病变形成中的作用。方法建立日本血吸虫感染C57BL/6小鼠模型,感染后2、4、6、8、10和12周剖杀小鼠,用实时荧光定量PCR法检测小鼠肝脏白介素17(IL-17)、IL-6、转化生长因子-β(TGF-β)、肿瘤坏死因子-α(TNF-α)、IL-23、炎症趋化因子(CX-CL1、CXCL2和CCL11)mRNA水平;ELISA法检测肝脏IL-17、CXCL1、CXCL2和CCL11蛋白水平;肝脏石蜡切片,HE染色后动态观察小鼠肝脏虫卵肉芽肿大小。结果 IL-17、IL-6、TNF-α、IL-23、CXCL1、CXCL2、CCL11 mRNA水平于感染后6、8周明显高于正常对照;且细胞因子IL-17及趋化因子CXCL1、CXCL2和CCL11蛋白分泌水平显著升高(P<0.05);HE染色显示感染第4周小鼠肝脏出现虫卵肉芽肿,第6周肉芽肿反应达高峰,第8、10周虫卵肉芽肿缩小,周围出现成纤维细胞,第12周时肉芽肿明显缩小,部分肝细胞变性、坏死、有炎症细胞浸润,虫卵周围可见到少量梭形的成纤维细胞及类上皮细胞。结论 IL-17在日本血吸虫感染小鼠肝脏肉芽肿病变过程中可能是一种具有重要作用的调节因子,参与肝脏肉芽肿形成。

Objective To observe the dynamic changes of the Th17-related inflammatory cytokines and chemokines in the liver of C57BL /6 mice infected with Schistosoma japonicum,and explore the role in granuloma formation.Methods Mice were infected subcutaneously with cercariae of Schistosoma japonicum,and then sacrificed in 2,4,6,8,10 and 12 weeks after infection.Interleukin-17（IL-17）,IL-6,transforming growth factor-β（TGF-β）,tumor necrosis factor-α（TNF-α）,IL-23,CXCL1,CXCL2 and CCL11 mRNA levels in the mice liver were measured by using real time quantitative PCR.Liver IL-17,CXCL1,CXCL2 and CCL11 protein levels were determined by ELISA assay.Liver samples were embedded in paraffin for routine histological examination.The sizes of egg granuloma were observed dynamically by HE stain.Results IL-17,IL-6,TGF-β,TNF-α,IL-23,CXCL1,CXCL2 and CCL11 mRNAs were expressed strongly at the 6th and 8th week of infection,and which mRNAs were higher than those in the control mouse（P0.05）.Furthermore,IL-17,CXCL1,CXCL2 and CCL11 protein secretion levels were significantly increased compared with the control mouse（P0.05）.Egg granuloma presented at the 4th week of infection and the size reached maximum at the 6th week.Thereafter,the granuloma became smaller,and it was finded that a few of fibre cells were around the eggs at the 6th and 8th week after exposition.The egg granuloma got smaller significantly at the 12th week,furthermore,part of the liver cell degeneration,necrosis and infiltration of inflammatory cells,the small spindle-shaped fibroblasts and epithelioid cells could be seen around the eggs.Conclusion These results demonstrate that IL-17 may be play an important role in the development of granuloma of the liver in the mouse infected with Schistosoma japonicum.