Effect of change in high mobility group protein box 1 expression on activity of immunocytes in spleen of mice with multiple organ dysfunction syndrome

Abstract

To explore the regularity of high mobility group protein box 1 (HMGB1) expression and major histocompatibility complex II I-A(b) in spleen of mice with multiple organ dysfunction syndrome (MODS) , and its effect on the activity of immunocytes and relationship with pathogenesis of MODS. MODS model was replicated by injecting zymosan into abdominal cavity of mice. The mice were randomly divided into normal control group, and 3, 8, 12 hours, and 1, 2, 3, 5, 10-12 days after injection groups. The expression levels of HMGB1, I-A(b) and apoptosis rate in the spleen were detected. There was a little HMGB1 expression in the spleen of control mice. After zymosan administration, HMGB1 expression was increased, it reached the highest level on 1-2 days (P<0.01), decreased on day 5, then elevated on 10-12 days (P<0.05). Change in HMGB1 mRNA expression was in accordance with that of the protein. At 8 hours following injury, the I-A(b) expressed on the splenocytes was enhanced similar to that of HMGB1, and then it reversed. The occurrence of splenocyte apoptosis was also consistent with change in HMGB1 content in the spleen. The increased apoptosis of splenocytes in mice with MODS is closely related with up-regulation of HMGB1 expression, which inhibits the expression level of I-A(b) on antigen presenting cells, thus weakens the capability of immune responses and affected the development of MODS.