IL-6介导JAK/STAT信号通路在胶原诱导性关节炎大鼠抑郁发生中的作用机制研究

IL-6-mediated JAK/STAT signaling pathway in development of depression in rats with collagen induced arthritis

目的:研究IL-6介导Janus蛋白酪氨酸激酶/信号转导及转录激活子(JAK/STAT)信号通路在胶原诱导性关节炎(CIA)大鼠抑郁发生中的作用及对突触可塑性的影响。方法:56只SD大鼠取10只设为健康组,其余46只建立CIA模型,建模成功37只,取10只设为CIA模型组,其余建立CIA伴抑郁模型,建模成功22只随机分为CIA伴抑郁模型组、干预组,各11只。干预组采用抗白介素-6受体(IL-6R)单克隆抗体溶液腹腔注射,剂量40 mg/kg,健康组、CIA模型组、CIA伴抑郁模型组腹腔注射等量乳酸钠林格氏液。采用ELISA法测定血清IL-6水平;HE染色观察各组海马组织病理变化,采用电子显微镜观察突触界面结构变化,比较各组海马突触可塑性;采用Western blot测定海马组织JAK2、p-JAK2、STAT3、p-STAT3蛋白相对表达量,比较p-JAK2/JAK2、p-STAT3/STAT3。结果:CIA模型组血清IL-6水平高于健康组(P<0.05),CIA伴抑郁模型组高于CIA模型组、健康组(P<0.05),干预组低于CIA模型组、CIA伴抑郁模型组(P<0.05),高于健康组(P<0.05)。HE染色结果显示,CIA模型组细胞层次减少,结构模糊,部分发生核固缩、核深染变化,CIA伴抑郁模型组神经元细胞病变更为明显,干预组有所改善。电镜观察显示,CIA模型组突触结构部分溶解,界限较为清晰,突触囊泡多,CIA伴抑郁模型组变化更为明显,干预组有所改善。CIA模型组突触后致密物厚度(PSD)、活性区长度均小于健康组(P<0.05);CIA伴抑郁模型组PSD、活性区长度小于CIA模型组、健康组(P<0.05);干预组PSD、活性区长度大于CIA模型组、CIA伴抑郁模型组(P<0.05),小于健康组(P<0.05);CIA模型组海马组织p-JAK2/JAK2、p-STAT3/STAT3高于健康组(P<0.05),CIA伴抑郁模型组高于CIA模型组、健康组(P<0.05),干预组低于CIA模型组、CIA伴抑郁模型组(P<0.05),高于健康组(P<0.05)。结论:IL-6介导JAK/STAT信号通路参与CIA伴抑郁进展过程,下调IL-6可抑制CIA抑郁并发症的进展,可能通过阻断JAK/STAT信号通路改善海马组织病理变化及海马突触界面结构变化,减轻突触可塑性损伤发挥作用。

Objective:To study the role of IL-6 mediated Janus protein tyrosine kinase/signal transducer and activator of transcription(JAK/STAT)signaling pathway in the occurrence of depression in collagen-induced arthritis(CIA)rats and its countermeasures the influence of synaptic plasticity.Methods:56 SD rats were selected and set 10 cases as healthy group. The remaining 46 cases established CIA models,37 cases of which were successfully modeled,and 10 cases were retained as CIA model groups. The rest were established with CIA with depression models. 22 cases of them were randomly divided into CIA with depression model group and intervention group,11 cases in each group. The intervention group was injected intraperitoneally with anti-interleukin-6 receptor(IL-6 R)monoclonal antibody solution at a dose of 40 mg/kg. The healthy group,the CIA model group,and the CIA with depression model group were peritoneally injected with an equal amount of sodium lactate Ringer’s solution. The serum IL-6 level was determined by ELISA. HE staining was used to observe the pathological changes of hippocampus in each group,and electron microscope was used to observe the changes of synaptic interface structure,and the hippocampal synaptic plasticity of each group were compared. Western blot was used to determine the relative expression levels of JAK2,p-JAK2,STAT3,and p-STAT3 proteins in hippocampus,and to compare p-JAK2/JAK2,p-STAT3/STAT3.Results:The levels of IL-6 in the CIA model group was higher than those in the healthy group(P<0.05),which of the CIA model with depression group was higher than that of the CIA model group and healthy group(P<0.05),which of the intervention group was lower than that of the CIA model group,CIA with depression model group(P<0.05),which was higher than that of the healthy group(P<0.05). The level of cells in the CIA model group was reduced,the structure was blurred,and some of the nuclear shrinkage and nuclear deep staining occurred. The neuronal cell lesions in the CIA with depression model group were more obvious. Which of the intervention group were improved. Electron microscopic observation showed that the CIA model group partially dissolved the synapse structure,the boundaries were clearer,and there were more synaptic vesicles. The CIA model group with depression had more obvious changes and the intervention group had improved. The thickness of the post-synaptic compact(PSD)and the length of the active area in the CIA model group were shorter than those in the healthy group(P<0.05),which of the CIA with depression model group were shorter than those in the CIA model group and healthy group(P<0.05),which of intervention group were larger than those in CIA model group and CIA with depression model group(P<0.05). The p-JAK2/JAK2,pSTAT3/STAT3 in hippocampus in the CIA model group was higher than those in the healthy group(P<0.05),which of the CIA model group with depression was higher than that of the CIA model group and healthy group(P<0.05),which of the intervention group was lower than that of the CIA model group,CIA with depression model group(P<0.05),which was higher than that of the healthy group(P<0.05).Conclusion:IL-6 mediates JAK/STAT signaling pathway to participate in the progression of CIA with depression. Downregulation of IL-6 can inhibit the progression of CIA depressive complications. It may improve the pathological changes of hippocampus tissue and hippocampal synaptic interface by blocking JAK/STAT signaling pathway Structural changes play a role in reducing synaptic plasticity damage.