Worsened brain edma and the level of serum HMGB1 and S100B of IL-4 knockout mice after traumatic brain injury

Abstract

Objective To investigate the changes of brain edma and expression of blood high mobility group box 1(HMGB1) and calcium binding protein S100B after traumatic brain injury (TBI) in IL-4 knockout (IL-4 KO) mice, and to explore the effects of IL-4 on traumatic brain injury. Methods Twenty male wild type (WT) or twenty male IL-4 KO BALB/cJ mice were randomly divided into WT sham TBI group, WT TBI group, IL-4 KO sham TBI group and IL-4 KO TBI group(n=10 in each group). The model of traumatic brain injury was established by the free falling body epidural impact method, then the brain water content was measured.The expression of aquaporin-4 (APQ4) and HMGB1 in injured brain of each group was detected by Western blot, and the concentration of HMGB1 and S100B in serum was detected by ELISA assay. Results (1) The brain water content of injured lateral brain of BALB/cJ mice with IL-4 gene knockout was significantly higher than that of wild type mice with brain injury model (WT group: (80.03±0.35)%; IL-4 KO group: (81.93±0.41)%; P<0.05). (2) The Western blot showed that the expression of AQP4 and HMGB1 in brain tissue of BALB/cJ mice with IL-4 gene knockout was significantly higher than those in wild type mice after traumatic brain injury.(3) The results of ELISA showed that the levels of HMGB1 and S100B in the serum of IL-4 knockout BALB/cJ mice were significantly higher than those of wild type mice (HMGB1: WT group: (9.21±0.74)ng/ml; IL-4 gene knock-out group: (13.39±1.33)ng/ml, P<0.05; S100B protein: WT group: (11.11±0.84)pg/ml; IL-4 KO group: (18.11±2.02)pg/ml, P<0.05 ). Conclusion The brain tissue water content and the expression of APQ4 are increased in IL-4 KO TBI mice.The expression of HMGB1 in brain issue and serum and S100B in serum are also up-regulated. Key words: Traumatic brain injury; Interleukin-4; Brain edema; High mobility group box 1; Calcium binding protein S100B; Mice