Song G Y, Chung C S, Chaudry I H, Ayala A
Center for Surgical Research, Brown University School of Medicine, Providence, Rhode Island 02903, USA.
J Surg Res. 2000 Jun 15;91(2):141-6. doi: 10.1006/jsre.2000.5928.
Studies have indicated that a shift from a Th1 to a Th2 response occurs that contributes to the late immunosuppression seen during sepsis. However, the mechanism by which this occurs is unknown. In this regard, mediators released in response to sepsis are thought to upregulate a family of stress-induced mitogen-activated protein kinases (MAPKs), such as JNK, ERK, and p38 MAPK, which may play a role in this process.
To determine the role of MAPK in immune suppression, we induced polymicrobial sepsis in C3H/HeN male mice using cecal ligation and puncture (CLP). Splenic lymphocytes were harvested 24 h post-CLP and stimulated with the T-cell mitogen concanavalin A, and the expression and activation of these MAPKs were assessed by Western analysis. To determine the extent to which these MAPKs may have an impact on splenic immune function, cells were pretreated with a 10 microM concentration of the p38 MAPK inhibitor SB203580 or the MEK inhibitor PD98059 or with DMSO vehicle. The cells were then stimulated with 2.5 microg/ml of the T-cell mitogen concanavalin A, and cytokine release was then determined (by ELISA).
In the lymphocytes from CLP mice no JNK signal was detected, however, p38 expression and activation were markedly (P < 0.05, n = 6) increased. In contrast, the expression of activated ERK markedly decreased following septic challenge. The results indicate that p38 MAPK inhibition with SB203580 suppressed the sepsis-induced augmentation of interleukin-10 release while restoring the suppressed Th1 cytokine interleukin-2 release typically encountered following sepsis. Inhibition of ERK had no effect on cytokine release. Neither PD98059 nor SB203580 had an effect on interferon gamma release or on proliferative capacity.
This would indicate that the induction of p38 MAPK activation in splenocytes contributes to the immunosuppression seen in late sepsis.
研究表明，脓毒症期间会出现从Th1反应向Th2反应的转变，这导致了后期的免疫抑制。然而，这种转变发生的机制尚不清楚。在这方面，脓毒症反应中释放的介质被认为会上调应激诱导的丝裂原活化蛋白激酶（MAPK）家族，如JNK、ERK和p38 MAPK，它们可能在这一过程中发挥作用。
为了确定MAPK在免疫抑制中的作用，我们采用盲肠结扎穿刺（CLP）法在C3H/HeN雄性小鼠中诱导多菌性脓毒症。CLP术后24小时收集脾淋巴细胞，并用T细胞丝裂原伴刀豆球蛋白A刺激，通过蛋白质免疫印迹分析评估这些MAPK的表达和激活情况。为了确定这些MAPK对脾免疫功能的影响程度，细胞先用10微摩尔浓度的p38 MAPK抑制剂SB203580或MEK抑制剂PD98059或二甲基亚砜（DMSO）载体进行预处理。然后用2.5微克/毫升的T细胞丝裂原伴刀豆球蛋白A刺激细胞，随后测定细胞因子释放（通过酶联免疫吸附测定法）。
在CLP小鼠的淋巴细胞中未检测到JNK信号，然而，p38的表达和激活显著（P < 0.05，n = 6）增加。相反，脓毒症刺激后活化ERK的表达明显下降。结果表明，用SB203580抑制p38 MAPK可抑制脓毒症诱导的白细胞介素-10释放增加，同时恢复脓毒症后通常出现的被抑制的Th1细胞因子白细胞介素-2释放。抑制ERK对细胞因子释放没有影响。PD98059和SB203580对干扰素γ释放或增殖能力均无影响。
这表明脾细胞中p38 MAPK激活的诱导有助于脓毒症后期出现的免疫抑制。
