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

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 non-sensitized 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.