Objective: To explore the protective effect of electroacupuncture against acute lung injury (ALI) in septic rats and explore the mechanism.
Methods: Sixty male SD rats were randomly divided into cecal ligation and puncture (CLP)-induced sepsis group (n=45) and sham operation group (n=15; with laparotomy but without CLP). The rat models of sepsis were randomized into ALI group (n=15) without further treatment, ALI + SEA group (n=15) treated with electroacupuncture at the point far from the Zusanli acupoint for 30 min, and ALI + EA group (n=15) with electroacupuncture at Zusanli with identical frequency, intensity and duration of electrical stimulation. All the rats were sacrificed at 12 h after CLP for measurement of the weight and the wet/dry weight (W/D) ratio of the lungs. Pathological changes of the lung tissues were examined using HE staining, and the contents of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the homogenate of the lung tissues were detected using enzyme-linked immunosorbent assay (ELISA). TUNEL staining was used to detect the apoptotic cells, and the expressions of Bax, caspase-3 and the important proteins in the JAK1/STAT3 signaling pathway (JAK1 and STAT3) were detected with Western blotting.
Results: Compared with those in the sham operation group, the rats in ALI group showed obvious lung pathologies with significantly increased lung W/D ratio (P < 0.01), pulmonary expressions of TNF-α and IL-6 (P < 0.01), and obvious up-regulation of JAK1, STAT3, caspase-3, and Bax expressions (P < 0.01); similar changes were also observed in ALI+SEA group (P > 0.05). Compared with those in ALI+SEA group, the rats in ALI+EA group showed significantly milder lung pathologies, lowered lung W/D ratio (P < 0.01) and decreased pulmonary expressions of TNF-α, IL-6, JAK1, STAT3, caspase-3 and Bax (P < 0.01).
Conclusions: Electroacupuncture can inhibit the release of inflammatory mediators and cell apoptosis via the JAK1/STAT3 pathway to reduce lung injuries in septic rats.
目的: 探讨电针对脓毒症大鼠急性肺损伤的影响及作用机制。
方法: 采用SPF级SD大鼠60只，用随机数字表法分组。假手术组(SHAM)15只：只开腹而不结扎盲肠; 脓毒组共45只，采用盲肠结扎穿孔制术(CLP)脓毒症肺损伤模型制备，制备成功后随机分为脓毒症急性肺损伤组(ALI)15只：不做进一步处理; 脓毒症急性肺损伤+电针非穴位组(ALI+SEA)15只、脓毒症急性肺损伤+电针穴位组(ALI+EA)15只：针刺双侧内关穴及足三里，电刺激的频率、强度与时间与ALI+SEA组保持一致。于CLP后12 h后处死大鼠，称量大鼠肺组织，测定大鼠肺组织湿/干重比值(W/D)，HE染色检测肺组织病理变化，Tunel染色计算肺组织凋亡细胞比例，酶联免疫吸附试验(ELISA)检测大鼠肺组织中肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)的浓度，蛋白质免疫印迹试验(Western blot)检测凋亡相关蛋白Bax、Caspase-3表达以及核转录因子JAK1/STAT3信号通路中重要蛋白JAK1、STAT3的表达。
结果: ALI与SHAM相比呈现出明显的肺损伤病理表型，表现为肺湿/干重比值增加(P < 0.01)，血清中TNF-α和IL-6水平显著上升(P < 0.01)，组织内JAK1、STAT3、Caspase-3、Bax表达水平显著上调(P < 0.01);ALI+SEA与ALI相比以上指标无显著性变化(P > 0.05);ALI+EA与ALI+SEA组比，能显著的减轻脓毒症诱发的肺部病理变化，表现为肺湿/干重比值升高受到抑制(P < 0.01)，血清中TNF-α和IL-6上升得到缓解(P < 0.01)，组织中JAK1、STAT3、Caspase-3、Bax的表达升高显著下调(P < 0.01)。
结论: 电针可关联JAK1/STAT3通路的机制，抑制脓毒症大鼠炎性介质的释放及细胞凋亡，减轻脓毒症大鼠的肺损伤。
Keywords: JAK1/STAT3 pathway; acute lung injury; electroacupuncture; sepsis.