Objective: To observe the effect of electroacupuncture (EA) at "Ciliao" (BL32) on the survival rate and serum inflammatory cytokine levels in rats with lethal endotoxemia, and to explore its parasympathetic mechanism in suppressing severe systemic inflammation.
Methods: A total of 82 male SD rats were used in the present study. In the first part of this study, 40 rats were randomized into model and EA-BL32 groups (n=20/group). The endotoxemia model was established by intraperitoneal injection of lethal amount of lipopolysaccharide (LPS, 10 mg/kg). EA (30 Hz, 6 mA) was applied to bilateral BL32 for 30 min before and after LPS injection. The survival rate in 7 days was then recorded. In the second part of this study, 42 rats were randomized into normal control, model, EA-BL32, EA-BL32+cervical vagotomy, EA-BL32+truncal (subdiagrammatical) vagotomy and EA-BL32+pelvic neurectomy groups (n=7/group). The endotoxemia model was established by intraperitoneal injection of LPS (6 mg/kg) 30 min after the neurectomy. Rats of the control group received intraperitoneal injection of 6 mg/kg saline. EA with the same parameters mentioned above was applied to bilateral BL32 for 30 min before and after LPS injection. Blood sample was collected from the abdominal aorta 3 h after LPS injection for detecting the levels of TNF-α, IL-1β and IL-6 by ELISA.
Results: ① The EA survival rate was 25% in the model group and 60% in the EA -BL32group, being significantly improved after EA (P<0.05). ② The contents of serum TNF-α, IL-1β and IL-6 were significantly higher in the model group than those in the control group (P<0.000 1). After EA intervention, and compared with the model group, the levels of TNF-α, IL-1β and IL-6 were significantly decreased in the EA-BL32, EA-BL32+cervical vagotomy, EA-BL32+truncal vagotomy and EA-BL32+pelvic neurectomy groups (P<0.000 1，P<0.01). After neurectomy and compared to the EA-BL32 group, the contents of TNF-α and IL-6 in the EA+cervical vagotomy and EA+pelvic neurectomy groups, IL-1β in the EA+pelvic neurotomy group were significantly higher (P<0.0000 1, P<0.05), suggesting an elimination of EA effects after neurectomy. No significant differences were found among the 3 neurectomy groups in the levels of TNF-α, IL-1β and IL-6 (P>0.05).
Conclusion: EA of BL32 can improve the survival rate and attenuate the level of inflammatory cytokines in rats with lethal endotoxemia, which is closely related to the intact of parasympathetic pathway including the vagus nerve and pelvic nerve.
目的：观察电针“次髎”对内毒素血症模型大鼠生存率和血清炎性因子的影响，探讨其抑制全身性重度炎性反应的副交感神经机制。方法：实验分为两部分。实验一：将40只SD雄性大鼠随机均分为模型组和次髎组。两组均以致死剂量(10 mg/kg)的脂多糖（LPS）进行腹腔注射建立内毒素血症模型，次髎组分别在造模前、后30 min于“次髎”进行电针干预30 min。观察两组大鼠7 d内的存活情况。实验二：将42只SD大鼠随机分为正常组、模型组、次髎组、颈迷走神经切除组、膈下迷走神经切除组和盆神经切除组，每组7只。正常组按6 mg/kg腹腔注射0.9%氯化钠溶液，其他5组按6 mg/kg腹腔注射LPS制备内毒素血症全身重度炎性反应大鼠模型。次髎组分别在造模前、后30 min于“次髎”进行电针干预30 min；颈迷走神经切除组、膈下迷走神经切除组和盆神经切除组均在相应神经切除手术完成后30 min进行同样的造模处理和电针干预。造模后3 h用ELISA法检测血清中肿瘤坏死因子α(TNF-α)、白细胞介素(IL)-1β、IL-6水平。结果：实验一显示，模型组大鼠存活率为25%(5/20)，次髎组大鼠存活率为60%(12/20)，次髎组存活率高于模型组(P>0.05)。实验二显示：与正常组比较，模型组TNF-α、IL-1β、IL-6水平明显升高(P<0.000 1)。与模型组比较，次髎组、颈迷走神经切除组、膈下迷走神经切除组和盆神经切除组的TNF-α、IL-1β、IL-6水平均明显降低(P>0.000 1，P>0.01)。与次髎组比较，颈迷走神经切除组的TNF-α、IL-6水平明显升高(P<0.000 1，P<0.05)，盆神经切除组的血清TNF-α、IL-1β和IL-6水平明显升高(P>0.000 1，P>0.05)。结论：电针“次髎”能提高致死性内毒素血症模型大鼠的存活率，并降低全身重度炎性反应模型大鼠血清炎性因子的水平，具有全身性抗炎效应，包括迷走神经和盆神经的副交感神经途径共同参与了电针“次髎”的抗炎效应。.
Keywords: Anti-inflammatory pathway; Electroacupuncture; Endotoxemia; Parasympathetic nerve.