Luo Yan, Liang Huaping, Hu Chenxiang, Xu Xiang, Wang Zhengguo
Research Institute of Field Surgery, Daping Hospital, Third Military Medical University, Chongqing 400042, China.
Chin Med J (Engl). 2002 Sep;115(9):1348-51.
To investigate whether the decrease in expression of interleukin-2 (IL-2) after trauma is associated with changes in DNA binding activity of nuclear factor of activated T cells (NFAT) and activator protein-1 (AP-1).
Mice with closed impact injury with fracture in both hind limbs were adopted as the trauma model. Spleen lymphocytes were isolated from traumatized mice and stimulated with Con-A. Culture supernatants were assayed for IL-2 activity, and total RNA was extracted from spleen lymphocytes and assayed for IL-2 mRNA. DNA binding activity of NFAT and AP-1 were measured by electrophoretic mobility shift assay (EMSA). The expression of c-Fos, c-Jun and JunB proteins was determined by the Western blot analysis.
DNA binding activity of NFAT and AP-1 gradually decreased to a minimum of 41% and 49%, respectively, of the control on the 4th day after injury, which was closely followed by the decline in IL-2 activity and IL-2 mRNA. A decrease in the expression of c-Fos on the 1st and 4th day after trauma had no significant effect on c-Jun expression; the increase in expression of JunB was only on the 1st day after injury.
Decreased IL-2 expression is, at least in part, due to a decline in the activation of NFAT and AP-1 in traumatized mice. The decline in DNA binding activity of NFAT and AP-1 is partly due to a trauma-induced block in the expression of c-Fos.
探讨创伤后白细胞介素-2（IL-2）表达的降低是否与活化T细胞核因子（NFAT）及活化蛋白-1（AP-1）的DNA结合活性变化有关。
采用双后肢闭合性撞击骨折小鼠作为创伤模型。从创伤小鼠中分离脾淋巴细胞，用刀豆球蛋白A刺激。检测培养上清液中的IL-2活性，从脾淋巴细胞中提取总RNA并检测IL-2 mRNA。通过电泳迁移率变动分析（EMSA）测定NFAT和AP-1的DNA结合活性。采用蛋白质印迹分析测定c-Fos、c-Jun和JunB蛋白的表达。
NFAT和AP-1的DNA结合活性在伤后第4天分别逐渐降至对照组的最低水平，分别为41%和49%，随后IL-2活性和IL-2 mRNA随之下降。创伤后第1天和第4天c-Fos表达的降低对c-Jun表达无显著影响；JunB表达仅在伤后第1天增加。
IL-2表达降低至少部分是由于创伤小鼠中NFAT和AP-1的活化下降。NFAT和AP-1的DNA结合活性下降部分是由于创伤诱导的c-Fos表达受阻。
