山药多糖对脓毒症大鼠心肌损伤及JAK2/STAT3信号通路的影响

Effects of yam polysaccharide on myocardial injury and JAK2/STAT3 signal pathway in septic rats

[目的]探索山药多糖(RDPS-Ⅰ)对脓毒症大鼠心肌损伤及酪氨酸蛋白激酶2(JAK2)/信号转导和转录激活因子3(STAT3)信号通路的影响。[方法]将90只大鼠随机分为RDPS-Ⅰ低(1.0 g/kg)、中(2.0 g/kg)、高(3.0 g/kg)剂量组及模型组、阳性对照组、假手术组。通过取出盲肠进行结扎、穿孔的方法复制脓毒症大鼠,造模完成后,RDPS-Ⅰ低、中、高剂量组分别给予相应剂量RDPS-Ⅰ灌胃,阳性对照组予以200 mg/kg剂量皮下注射4 mL/kg的氨苄西林溶液,其余两组给予生理盐水,每12 h干预1次,连续干预6天。干预结束后,检测大鼠血流动力学指标平均动脉压(MAP)、左心室收缩压(LVSP)、心率(HR);苏木精-伊红(HE)染色观察脓毒症大鼠心肌组织病理学变化;TUNEL染色检测脓毒症大鼠心肌细胞凋亡;酶联免疫吸附法(ELISA)测定大鼠血清中炎症因子水平;Western blot检验大鼠心肌组织中JAK2/STAT3信号通路蛋白表达水平。[结果]相比于假手术组,模型组大鼠心肌组织排列紊乱,出现严重炎症细胞浸润现象,LVSP、HR、MAP降低56%、54%、55%(P<0.05),血清肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、白细胞介素1β(IL-1β)、核因子κB(NF-κB)水平及心肌组织中p-JAK2/JAK2、p-STAT3/STAT3和细胞凋亡率分别增加2.25、1.94、1.99、1.99、2.96、2.26、3.67倍(P<0.05);与模型组相比,经RDPS-Ⅰ干预,大鼠心肌组织排列紊乱程度、炎症细胞浸润程度均逐渐缓解,RDPS-Ⅰ低剂量组LVSP、HR、MAP分别增加了0.54、0.35、0.34倍,TNF-α、IL-6、IL-1β、NF-κB水平和心肌组织中p-JAK2/JAK2、p-STAT3/STAT3及细胞凋亡率分别降低28%、19%、18%、26%、27%、29%、25%;RDPS-Ⅰ中剂量组LVSP、HR、MAP分别增加了0.92、0.67、0.83倍,TNF-α、IL-6、IL-1β、NF-κB水平及心肌组织中p-JAK2/JAK2、p-STAT3/STAT3和细胞凋亡率分别降低45%、41%、40%、50%、49%、50%、50%;RDPS-Ⅰ高剂量组LVSP、HR、MAP分别增加了1.21、1.10、1.15倍(P<0.05),TNF-α、IL-6、IL-1β、NF-κB水平及心肌组织中p-JAK2/JAK2、p-STAT3/STAT3和细胞凋亡率分别降低64%、63%、63%、66%、70%、66%、70%(P<0.05)。[结论]RDPS-Ⅰ可以减轻炎症反应,改善脓毒症大鼠心肌损伤和功能障碍,可能与抑制JAK2/STAT3信号通路有关。

Aim To explore the effects of yam polysaccharide(RDPS-Ⅰ)on myocardial injury and tyrosine protein kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3)signaling pathway in septic rats.Methods Ninety rats were randomly divided into:RDPS-Ⅰlow(1.0 g/kg),medium(2.0 g/kg),and high(3.0 g/kg)dose groups,model group,positive control group and sham operation group.The cecal ligation and perforation method was used to establish a sepsis rat model,after the model was completed,RDPS-Ⅰlow,medium and high dose groups were given corresponding dose yam polysaccharide by gavage respectively;The positive control group was given 200 mg/kg subcutaneous injection of 4 mL/kg ampicillin solution;The other two groups were given normal saline,and intervened once every 12 hours,for 6 consecutive days.After the intervention,the hemodynamic indicators of the rats were measured,including mean arterial pressure(MAP),left ventricular systolic pressure(LVSP),and heart rate(HR);Hematoxylin-Eosin(HE)staining was used to observe the pathological changes of septic rat myocardium;TUNEL staining was used to detect cardiomyocyte apoptosis of septic rat;enzyme-linked immunosorbent assay(ELISA)was used to determine the levels of inflammatory cytokines in septic rat serum;Western blot was used to test the expression level of JAK2/STAT3 signaling pathway proteins in rat myocardial tissue.Results Compared with the sham operation group,the myocardial tissue was disordered and occurred with severe inflammatory cell infiltration in the model group;LVSP,HR,MAP decreased by 56%,54%,55%(P<0.05).The levels of tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),interleukin-1β(IL-1β),and nuclear factor-κB(NF-κB)in serum and p-JAK2/JAK2,p-STAT3/STAT3 and apoptosis rates in myocardial tissue were increased by 2.25,1.94,1.99,1.99,2.96,2.26 and 3.67 times(P<0.05),respectively.Compared with model group,the degree of myocardial tissue disorder and inflammatory cell infiltration were gradually relieved after RDPS-Ⅰintervention;LVSP,HR and MAP increased by 0.54,0.35 and 0.34 times in low dose RDPS-Ⅰgroup,respectively;TNF-α,IL-6,IL-1β,NF-κB,p-JAK2/JAK2,p-STAT3/STAT3 and apoptosis rate decreased by 28%,19%,18%,26%,27%,29%,25%,respectively.LVSP,HR and MAP increased by 0.92,0.67 and 0.83 times in medium dose RDPS-Ⅰgroup,respectively.TNF-α,IL-6,IL-1β,NF-κB,p-JAK2/JAK2,p-STAT3/STAT3 and apoptosis rate decreased by 45%,41%,40%,50%,49%,50%,50%,respectively.LVSP,HR and MAP increased by 1.21,1.10 and 1.15 times in high dose RDPS-Ⅰgroup(P<0.05),respectively.TNF-α,IL-6,IL-1β,NF-κB,p-JAK2/JAK2,p-STAT3/STAT3 and apoptosis rate decreased by 64%,63%,63%,66%,70%,66%,70%(P<0.05),respectively.Conclusion Yam polysaccharide can reduce inflammation,and improve myocardial injury and dysfunction in septic rats,which may be related to the inhibition of JAK2/STAT3 signaling pathway.