Expression of HMGB1 and the antagonistic effects of ethyl pyruvate on synovium in collagen-induced arthritis rats / 中华风湿病学杂志

ABSTRACT

Objective In this study,we elucidated the role of high mobility group box chromosomal protein 1 (HMGB1) in collagen-induced arthritis (CIA) rat and the antagonist role of ethyl pyruvate by using a rat model of CIA as the research object by comparing the expression of HMGB1 in normal control group,CIA model group and ethyl pyruvate group.Methods Thirty-six rats were randomly divided into 3 groups (n=12):normal control group,CIA group and ethyl pyruvate group.Then the 6 rats were dissected at the 6th,9th week respectively.Thc expression of HMGB1 was analyzed by immunohistochemistry and Pathology-image analysis software in the cytoplasma.The expression of HMGB1 mRNA with real time-polymerse chain reaction (PCR) was evaluate,and the HMGB1 expression of each group were compared with t-test.Results The immunohistochemical results of HMGB1 showed that the expression intensity in the normal control group,CIA model group and ethyl pyruvate group was 2.1±0.6,7.3±1.2,6.0±1.2 respectively at the 6th week; and 2.2±0.7,12.4±4.5,5.5±1.0 at the 9th week respectively.The HMGB1 mRNA real time-PCR results had shown that the relative quantification of the normal control group and CIA model group were 1,2.865,2.602respectively at the 6th week and 1.005,4.694,1.729 at the 9th week.At those two points, the HMGB1 expressions of HMGB1 antagonist group were significantly higher than those of the normal controls (P＜0.05).In addition,there was statistical significant difference(P＜0.05) in the HMGB1 expression when compared with the placebo group.Furthermore, when the degree of HMGB1 expression among the three groups was compared,the HMGB1 antagonist group was decreased significantly (P＜0.05).Conclusion The results has demonstrated that HMGB1 could induce inflammation in the synovial tissue of CIA rats,and has provided the rationale that HMBG 1 could be the target of treating rheumatoid arthritis (RA).The results of this study have shown that ethyl pyruvate could antagonize the effect of HMGB1.This finding may provide a new therapeutic target for the treatment of RA.