电针足三里穴对肠缺血/再灌注大鼠肠通透性的影响

Effects of electroacupuncture at Zusanli points on gut permeability in rats with intestinal ischemia/reperfusion injury

目的：探讨电针足三里穴对肠缺血/再灌注（I/R）大鼠小肠促炎细胞因子引起的肠绒毛损伤及肠通透性的保护作用。方法将30只SD大鼠按随机数字表法分为肠I/R组（模型组）、肠I/R＋电针足三里穴组（电针足三里穴组）、肠I/R＋电针非经非穴组（电针非经非穴组），每组10只。采用夹闭肠系膜上动脉根部30 min、恢复灌注60 min的方法复制小鼠肠I/R损伤模型。电针足三里穴组于缺血后即刻电针双侧足三里穴30 min，强度为2～3 mA，频率2～100 Hz；电针非经非穴组采用相同频率和强度刺激足三里穴外侧旁开0.5 cm处30 min；模型组不进行任何治疗。于再灌注60 min处死各组动物，取远端回肠组织，检测肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）含量，光镜下观察肠组织病理改变并进行肠损伤评分。于再灌注30 min在肠袋中注入异硫氰酸荧光素（FITC）标记的葡聚糖，再灌注60 min后腹主动脉取血，测定血中FITC-葡聚糖含量，观察肠黏膜通透性的改变。结果与模型组和电针非经非穴组比较，电针足三里穴可显著抑制肠道TNF-α（pg/mg：3.01±0.50比8.65±1.02、8.42±1.41，均P＜0.05）和IL-6（pg/mg：2.51±0.15比6.34±0.86、6.13±1.12，均P＜0.05）水平，降低I/R造成的肠绒毛损伤评分（分：1.50±0.33比3.18±0.39、3.04±0.37，均P＜0.05）及肠黏膜FITC-葡聚糖含量（μg/L：282.42±73.92比856.22±229.47、844.22±239.47，均P＜0.05），模型组与电针非经非穴组上述指标比较差异无统计学意义（均P＞0.05）。模型组与电针非经非穴组肠组织病理改变无明显差异，肠绒毛顶端坏死、变钝、塌陷；电针足三里穴组动物肠绒毛损伤较模型组与电针非经非穴组减轻。结论电针足三里穴能显著抑制肠I/R大鼠肠道促炎细胞因子水平、减轻肠黏膜损伤，其对肠道的保护作用可能与电针足三里穴降低肠黏膜通透性有关。

Objective To investigate the protective effects of elctroacupuncture（EA）at Zusanli（ST36） points on intestinal villas damage and mucosal permeability induced by small intestine pro-inflammatory factors in rats with intestinal ischemia/reperfusion（I/R）. Methods 30 Sprague-Dawley（SD）rats were randomly divided into three groups（each,n=10）：intestinal I/R group（model group）,intestinal I/R＋EA ST36 group（EA group）and intestinal I/R＋sham EA group（SEA group）. Rats were subjected to superior mesenteric artery（SMA）clamping at its root part to occlude the vessel for 30 minutes,followed by reperfusion for 60 minutes to form intestinal I/R models. Rats in EA group received EA at the bilateral ST36 points（2-3 mA,2-100 Hz）for 30 minutes immediately after ischemia,those in SEA group received EA at bilateral sham points（the point was located at 0.5 cm away from ST36 point in its lateral side）with the same frequency and intensity of stimulation as EA group for 30 minutes,and those in model group received no treatment. Animals were sacrificed 60 minutes after reperfusion and segments of distal part of ileum were harvested,then the levels of tumor necrosis factor-α（TNF-α）and interleukin-6（IL-6）in intestinal tissue were measured. Histopathologic changes were viewed and graded via light microscopy. A solution of fluorescein isothiocyanate（FITC）-dextran was injected into the lumen of the segment of intestine 30 minutes after reperfusion,systemic blood was drawn via abdominal aorta puncture at 60 minutes after reperfusion,and then the level of FITC-dextran in blood was measured to determine the changes in intestinal permeability. Results Compared to the model group and SEA group,EA ST36 significantly attenuated intestine TNF-α（pg/mg：3.01±0.50 vs. 8.65±1.02,8.42±1.41,both P〈0.05）and IL-6 levels（pg/mg：2.51±0.15 vs. 6.34±0.86,6.13±1.12,both P〈0.05）,successfully maintained low gut injury scores（1.50±0.33 vs. 3.18±0.39,3.04±0.37,both P〈0.05）, and significantly reduced permeability of the distal ileum and the content of FITC-dextran（μg/L：282.42±73.92 vs. 856.22±229.47,844.22±239.47,both P〈0.05）. However,there were no significant differences in all above variables between SEA and model group（all P〉0.05）. Sections of distal ileum from animals in the model group and SEA group showed no obvious difference histologically,and the pathological manifestations were villous tip necrosis, blunt-shaped and collapse. Compared to the model group and SEA group,the intestinal villous injury in animals of EA group was much milder. Conclusion In rats with intestinal I/R injury,EA ST36 points has protective effect on the gut that is possibly due to the fact it may obviously lower the levels of the pro-inflammatory factors of small intestinal＆amp;nbsp;tissue,alleviate mucosal insult of gut and reduce the mucosal permeability.