补体调节蛋白CD55在三氯乙烯致敏小鼠免疫性肝损伤中的作用

Role of complement regulatory protein CD55 in the liver immune injury of trichloroethylene-sensitized mice

目的 检测三氯乙烯（TCE）致敏小鼠肝脏中补体调节蛋白CD55的表达水平,探讨其在补体介导的TCE所致小鼠免疫性肝脏损伤中的作用.方法 选取6～8周无特定病原体（SPF）级雌性BALB/c小鼠随机分成空白对照组（5只）、溶剂对照组（5只）和TCE处理组（15只）,建立BALB/c小鼠致敏模型,末次激发后24 h根据小鼠皮肤致敏反应评分将TCE处理组小鼠分为致敏组和未致敏组,并于末次激发后的48 h采血,无菌取小鼠肝脏组织.运用全自动生化分析仪检测小鼠肝功能指标谷丙转氨酶（ALT）,并对肝脏进行病理组织学观察,免疫组织化学（IHC）法检测肝脏中C5b-9沉积水平,IHC法及蛋白免疫印迹（Western blotting）法检测肝脏组织CD55蛋白表达变化情况,定量反转录聚合酶连锁反应（qRT-PCR）检测小鼠肝脏中CD55 mRNA表达水平.结果 TCE致敏组血清ALT水平明显高于溶剂对照组和TCE未致敏组,差异均有统计学意义（P＜0.05）.病理组织学结果显示,TCE致敏组肝细胞发生气球样变性、坏死.TCE致敏组肝脏组织C5b-9沉积水平明显高于溶剂对照组和TCE未致敏组,各组组化评分差异均有统计学意义（P＜0.05）;TCE致敏组CD55蛋白表达评分明显低于溶剂对照组和TCE未致敏组,差异均有统计学意义（P＜0.05）.Western blotting法结果显示,TCE致敏组CD55表达较溶剂对照组和TCE未致敏组降低,差异均有统计学意义（P＜0.05）.TCE致敏组肝脏组织CD55 mRNA表达水平明显低于溶剂对照组和TCE未致敏组,差异有统计学意义（P＜0.05）.结论 补体激活可能参与TCE致敏小鼠免疫性肝损伤过程,且补体调节蛋白CD55表达的改变可能在其中发挥重要作用.

Objective To explore the expression of CD55 in liver tissue of trichloroethylene-sensitized mice and discuss the role of CD55 in the liver immune injury of trichloroethylene-sensitized mice.Methods 6-8 weeks specific pathogen free female BALB/c were randomly divided into blank control group,solvent control group and TCE treatment group to establish BALB/c mice sensitized model According to mouse skin sensitization reaction score,TCE treatment mice were divided into sensitized and non-sensitized group at 24 h after the last challenge.At 48 h after the last challenge,the blood and aseptic livers were collected.The level of serum ALT was tested by automatic biochemical analyzer and pathology of the liver was observed.C5b-9 deposition was studied by immunohistochemistry （IHC）.CD55 protein expression level in liver tissue was studied by immunohistochemistry and Western blotting.The expression of CD55 mRNA in liver tissue was detected by qRT-PCR.Results Liver function test result showed level of serum ALT in TCE sensitized group was significantly higher than solvent control group and TCE non-sensitized group（P〈0.05）.There was ballooning degeneration and necrosis of liver cells in TCE sensitized group.IHC demonstrated that TCE sensitized group had obviously increased content of C5b-9 but had reduced content of CD55 compared with solvent control group and TCE nonsensitized group （P〈0.05）.Western blotting also showed that TCE sensitized group had lower expression of CD55 than solvent control group and TCE non-sensitized group （P〈0.05）.qRT-PCR showed that CD55 mRNA expression level in liver tissue of TCE sensitized group was apparently lower than solvent control group and TCE non-sensitized group （P〈0.05）.Conclusion Complement activation may be involved in TCE-induced liver injury,and the expression change of complement regulatory protein CD55 may play essential role in the process.