Objective: To observe the effect of electroacupuncture (EA) of "Baihui"(GV20), "Dazhui"(GV14), "Shenshu" (BL23)and "Zusanli"(ST36) on the intestinal flora and serum interleukin (IL)-1β and IL-18 contents in vascular dementia (VD) rats.
Methods: SD rats were randomized into sham operation, VD model, GV20+GV14+BL23 (EA-basic acupoints), and EA-basic acupoints+ST36 and EA-basic acupoints+probiotics groups (n=10 in each group). EA (10 Hz/50 Hz) was conducted for 30 min, once daily for 4 consecutive weeks. Rats of the EA-basic acupoints+probiotics received gavage of probiotics (2 mL/d containing 2.0×109 CFU of live bifidobacterium), once a day for 4 weeks, and those of the EA-basic acupoints and EA-basic acupoints+ST36 groups received gavage of the same dose of normal saline. The Morris water maze test was used to evalua-te the rats' lear-ning and memory ability before and after the treatment. The serum IL-1β and IL-18 levels were determined by ELISA, and the histopathological changes of the intestinal mucosa were observed by H.E. staining. The ultrastructural changes of hippocampal neurons were observed by using transmission electron microscopy and 16S rDNA sequencing technique was used to analyze the composition of intestinal microbiome.
Results: Compared with the sham operation group, the escape latency, serum levels of IL-1β and IL-18, as well as the relative abundance of harmful bacteria (including Catabacter, obinsoniella and Desulfovibrio) in the intestine were significantly increased (P<0.01). In comparison with the model group, the escape latency, serum levels of IL-1β and IL-18 in the three treatment groups, and the relative abundance of harmful bacteria (such as the Catabacter, Robinsoniella and Desulfovibrio) in the EA-basic acupoints+ST36 group were down-regulated obviously(P<0.05,P<0.01), and the relative abundance of Clostridiales-unclassified in both EA-basic acupoints+probiotics and EA-basic acupoints+ST36 groups was significantly up-regulated (P<0.05). The effects of EA-basic acupoints+ST36 and EA-ba-sic acupoints+probiotics were significantly superior to that of EA-basic acupoints in down-regulating IL-18 content (P<0.05). H.E. staining showed atrophy of the whole mucosal layer, loss of goblet cells, destruction of glands, infiltration of a large number of inflammatory cells, and transmission microscope displayed fuzziness of the nucleus membrane boundary, cystic dilation of the rough endoplasmic reticulum with unclear structure swelling of the mitochondria, and disordered arrangement or dissolution of the inner cristae in the model group, which was relatively milder in the EA-basic acupoints+ST36 and EA-basic acupoints+probiotics groups.
Conclusion: EA of GV20+GV14+BL23+ ST36 can improve the cognitive dysfunction of VD model rats, which may be related to its function in regulating the imbalance of intestinal microbiota, thereby inhibiting the peripheral inflammatory factor.
目的：观察电针对血管性痴呆大鼠肠道菌群及血清白细胞介素(IL)-1β、IL-18的影响。方法：采用改良双侧颈总动脉永久结扎法制备血管性痴呆大鼠模型, 将造模成功后的大鼠随机分为模型组、基础电针组、脑肠共治电针组、针药结合组, 每组10只, 另设假手术组10只。基础电针组给予“百会”“大椎”“肾俞”电针30 min；脑肠共治电针组采用基础电针组穴结合“足三里”电针30 min；针药结合组采用基础电针组穴结合益生菌灌胃联合治疗, 各组干预均每日1次, 连续4周。采用水迷宫实验评价各组大鼠治疗前后学习记忆能力, ELISA法测定血清IL-1β、IL-18含量, HE染色法观察肠黏膜形态学改变, 透视电镜观察大鼠海马神经元超微结构变化, 16S rDNA测序分析肠道菌群结构变化。结果：与假手术组相比, 模型组大鼠水迷宫实验逃避潜伏期延长(P<0.01), 肠黏膜损伤, 海马神经元明显减少, 血清中IL-1β、IL-18含量升高(P<0.01), 肠道中有害菌相对丰度增加。与模型组相比, 基础电针组、脑肠共治电针组、针药结合组逃避潜伏期缩短(P<0.05), 血清中IL-1β、IL-18含量降低（P<0.05,P<0.01）,肠黏膜和海马神经元损伤均轻于模型组, 肠道中有害菌相对丰度减少。与基础电针组相比, 脑肠共治电针组和针药结合组结肠黏膜和海马神经元病变均减轻, 血清中IL-18含量降低(P<0.05), 肠道菌群中有益菌相对丰度增加。结论：电针“百会”“大椎”“肾俞”“足三里”可改善血管性痴呆大鼠认知功能障碍, 其机制可能与通过调节肠道微生物群失衡状态, 从而抑制外周炎性因子IL-1β、IL-18的生成有关。.
Keywords: Brain-gut-microbiota axis; Curing brain disorders by treating intestines; Electroacupuncture; Inflammation; Vascular dementia.