THE DECLINE IN THE INDUCTION OF IL-2 EXPRESSION AFTER TRAUMA IS CORRELA TED TO CHANGES IN THE TRANSCRIPTION FACTOR NFAT / 解放军医学杂志

ABSTRACT

This study was designed to determine if the decrease in the expression of interleukin 2(IL 2) in spleen lymphocytes after trauma was associated with the changes in the transcription factor NFAT binding activity. Closed impact injury with fracture of both hind limbs in mice was adopted as the trauma model. Animals were sacrificed at the 12h and 1,4,7,10,14 days after injury. Spleen lymphocytes were isolated from traumatized mice and stimulated with concanavalin A, The culture supernatants were harvested and assayed for IL 2 activity. Total RNA was extracted from spleen lymphocytes and assayed for IL 2 mRNA. Nuclear protein was extracted,and DNA binding activity of NFAT was measured using an electrophoretic mobility shift assay(EMSA). The results showed that the DNA binding activity of NFAT gradually decreased , with trough value of NFAT binding activity ,accounting for 41% of the control, observed at 4d after injury. It was closely associated with the decline of IL 2 activity and IL 2 mRNA. These data suggest that the decline in the induction of IL 2 expression is,at least, partially due to the impairment in the activation of NFAT in traumatized mice. Taken together, the results are significant to clarify the mechanism of the decline in the induction of IL 2 expression after trauma.