Objectives: To observe the effect of electroacupuncture (EA) on the expressions of high mobility group protein 1(HMGB1) and myeloid differentiation factor 88 (MyD88) in the small intestine and intestinal flora of obese rats, so as to explore the potential mechanism of EA to improve obesity in rats.
Methods: After 1 week of acclimatization, 10 rats were randomly selected from 50 Wistar male rats as the normal group, and the rest rats were fed with high-fat diet for 8 weeks to establish the obese model. The successfully modeling rats were randomly divided into model group, EA group and sham EA group, with 10 rats in each group. Rats in the EA group were given EA (2 Hz, 1 mA) at "Zhongwan"(CV12), "Guanyuan"(CV4), "Zusanli" (ST36)and "Fenglong"(ST40). Rats in the sham EA group were given shallow stabs at acupoints of the EA group about 5 mm outwardly and the electrodes were clamped without being energized. Both groups were intervened for 10 min each time, 3 times (Monday, Wednesday and Friday) a week for 8 weeks. The body weights of the rats were measured before and after 8 weeks of intervention, respectively. The contents of serum lipopolysaccharide (LPS) and tumor necrosis factor (TNF)-α were measured by ELISA, and the protein and mRNA expressions of HMGB1 and MyD88 in the small intestine were detected by Western blot and real-time quantitative PCR, respectively. 16S rRNA sequencing was performed to determine the relative abundance and diversity of the bacterial flora in the fresh feces of rats.
Results: Compared with the normal group, the body weight, serum LPS and TNF-α contents, small intestinal HMGB1 and MyD88 protein and mRNA expression levels of rats in the model group were significantly increased (P<0.01), while the relative abundance of Lactobacillus, Muri and Bifidobacterium was decreased (p<0.01), Collinsella, Prevotella and Ruminococcus was increased (P<0.01). Compared with model group, the body weight, serum LPS and TNF-α contents, protein and mRNA expression levels of HMGB1 and MyD88 in both EA and sham EA groups were decreased (P<0.01, P<0.05), while the relative abundance of Lactobacillus, Muri and Bifidobacterium was increased (P<0.01) and Collinsella, Prevotella and Ruminococcus decreased (P<0.01). Comparison between EA group and sham EA group showed that, the contents of LPS and TNF-α in serum of rats in sham EA group were increased (P<0.01, P<0.05), the relative abundance of Lactobacillus, Muri and Bifidobacterium was lower (P<0.05, P<0.01), and Collinsella, Prevotella and Ruminococcus was higher (P<0.01).
Conclusions: EA can reduce the body weight of obese rats, which may be related to the regulation of the structure of intestinal flora and the reduction of inflammatory reactions in the small intestine.
目的: 观察电针对肥胖大鼠小肠高迁移率族蛋白1（HMGB1）、髓样分化因子88（MyD88）表达及肠道菌群的影响，探讨电针改善大鼠肥胖状态的机制。方法: 将50只雄性Wistar大鼠适应性饲养1周后，随机挑选10只大鼠作为正常组，其余大鼠给予高脂饮食喂养8周建立肥胖大鼠模型，将造模成功的大鼠按照随机数字表法分为模型组、电针组、假电针组，每组10只。造模结束后，电针组针刺“中脘”“关元”“足三里”“丰隆”，连接电针仪，频率2 Hz，强度1 mA，连续波。假电针组取电针组穴位向外旁开约5 mm处浅刺并夹持电极，不予通电。两组均每次干预10 min，每周3次，干预8周。分别在干预前和干预8周后测量大鼠体质量，用ELISA法检测大鼠血清脂多糖（LPS）、肿瘤坏死因子（TNF）-α的含量，Western blot法检测小肠组织HMGB1、MyD88的蛋白表达，实时荧光定量PCR法检测小肠组织HMGB1、MyD88的mRNA表达，16S rRNA测序技术检测大鼠新鲜粪便中肠道菌群相对丰度、多样性。结果: 与正常组比较，模型组大鼠体质量、血清LPS和TNF-α的含量、小肠组织HMGB1和MyD88的蛋白及mRNA表达水平均升高（P<0.01），乳酸菌属、Muri菌属、双歧杆菌属相对丰度降低（P<0.01），柯林斯菌属、普氏菌属、高氏瘤胃球菌属相对丰度升高（P<0.01）。与模型组比较，电针组及假电针组大鼠体质量、血清LPS和TNF-α的含量、小肠组织HMGB1和MyD88的蛋白及mRNA表达水平均降低（P<0.01，P<0.05），乳酸菌属、Muri菌属、双歧杆菌属相对丰度升高（P<0.01），柯林斯菌属、普氏菌属和高氏瘤胃球菌属相对丰度降低（P<0.01）。与电针组比较，假电针组大鼠血清LPS、TNF-α含量升高（P<0.01，P<0.05），乳酸菌属、Muri菌属、双歧杆菌属相对丰度降低（P<0.05，P<0.01），柯林斯菌属、普氏菌属、高氏瘤胃球菌属相对丰度升高（P<0.01）。结论: 电针能减轻肥胖大鼠体质量并改善外周炎性反应，其机制可能与其改善肠道菌群结构及菌群的相对丰度有关。.
Keywords: Electroacupuncture; Inflammatory reaction; Intestinal flora; Obesity.