[Effect of electroacupuncture at "Zusanli" (ST 36) on duodenal mast cells, NGF and NTRK1 in rats with functional dyspepsia]

Zhongguo Zhen Jiu. 2022 Jul 12;42(7):767-72. doi: 10.13703/j.0255-2930.20211230-k0003.
[Article in Chinese]

Abstract

Objective: To observe the effect of electroacupuncture (EA) at "Zusanli" (ST 36) on duodenal mast cells, nerve growth factor (NGF) and neurotrophic tyrosine kinase receptor type 1 (NTRK1), and to explore the mechanism of electroacupuncture at Zusanli (ST 36) on functional dyspepsia (FD).

Methods: Sixty SPF-grade 10-day-old SD rats were randomly divided into a normal group, a model group, a ketotifen group and an EA group, 15 rats in each group. The FD model was prepared by iodoacetamide combined with rat tail clamping method in the model group, the ketotifen group and the EA group. The rats in the ketotifen group were injected intraperitoneally with ketotifen (1 mgkg-1d-1) for 7 days; the rats in the EA group were treated with EA at bilateral "Zusanli" (ST 36), with disperse-dense wave, frequency of 2 Hz/50 Hz and intensity of 0.5 mA, 20 min each time, once a day for 14 days. The gastric emptying rate and small intestinal propulsion rate in each group were observed; the morphology of duodenal mucosa was observed by HE staining; the toluidine blue staining was used to observe the number and degranulation of mast cells in duodenal mucosa; the protein and mRNA expressions of NGF, NTRK1 in duodenum were detected by Western blot and real-time PCR; the level of interleukin-1β (IL-1β) in duodenum was measured by ELISA.

Results: Compared with the normal group, the gastric emptying rate and small intestinal propulsion rate in the model group were decreased (P<0.01); compared with the model group, the gastric emptying rate and small intestinal propulsion rate in the ketotifen group and the EA group were increased (P<0.01); the small intestinal propulsion rate in the EA group was higher than that in the ketotifen group (P<0.01). In the model group, local defects in duodenal mucosa were observed with a small amount of inflammatory cell infiltration; no obvious abnormality was found in duodenal mucosa of the other groups. Compared with the normal group, the mast cells of duodenal mucosa in the model group were increased significantly with significant degranulation; compared with the model group, the mast cells of duodenal mucosa in the ketotifen group and the EA group were decreased significantly, and the degranulation was not obvious. Compared with the normal group, the protein and mRNA expressions of NGF, NTRK1 as well as the level of IL-1β in duodenum in the model group were increased (P<0.01); compared with the model group, the protein and mRNA expressions of NGF, NTRK1 as well as the levels of IL-1β in duodenum in the ketotifen group and the EA group were decreased (P<0.01, P<0.05); compared with the ketotifen group, the mRNA expression of NGF, as well as the protein and mRNA expressions of NTRK1 in duodenum in the EA group were decreased (P<0.05, P<0.01).

Conclusion: EA at "Zusanli" (ST 36) could inhibit the activation of duodenal mast cells and regulate the expressions of NGF and its receptor to improve the low-grade inflammatory response of duodenum, resulting in treatment effect on FD.

目的:观察电针“足三里”对功能性消化不良(FD)大鼠十二指肠肥大细胞、神经生长因子(NGF)、神经营养因子酪氨酸激酶受体1(NTRK1)的影响,探讨电针足三里治疗FD的作用机制。方法:将60只出生10 d的SPF级幼年SD大鼠,随机分为正常组、模型组、酮替芬组、足三里组,每组15只。除正常组外,其余组大鼠均采用碘乙酰胺联合夹鼠尾法制备FD模型。酮替芬组腹腔注射酮替芬(1 mg•kg-1•d-1),连续注射7 d;足三里组于双侧“足三里”行电针干预,采用疏密波,频率2 Hz/50 Hz,电流强度0.5 mA,每次20 min,每天1次,连续14 d。观察各组大鼠胃排空率和小肠推进率;HE染色观察各组大鼠十二指肠组织形态;甲苯胺蓝染色观察大鼠十二指肠黏膜肥大细胞数量及脱颗粒情况;Western blot法和实时荧光定量PCR法检测大鼠十二指肠组织NGF、NTRK1蛋白及mRNA表达;ELISA法检测大鼠十二指肠组织白介素-1β(IL-1β)水平。结果:与正常组比较,模型组大鼠胃排空率和小肠推进率均降低(P<0.01);与模型组比较,酮替芬组与足三里组大鼠胃排空率和小肠推进率均升高(P<0.01);足三里组大鼠小肠推进率高于酮替芬组(P<0.01)。模型组大鼠十二指肠黏膜有局部缺损,有少量炎性细胞浸润;其他各组大鼠十二指肠黏膜未见明显异常。与正常组比较,模型组大鼠十二指肠黏膜肥大细胞明显增多且脱颗粒明显;与模型组比较,酮替芬组和足三里组大鼠十二指肠黏膜肥大细胞明显减少,且脱颗粒不明显。与正常组比较,模型组大鼠十二指肠组织NGF、NTRK1蛋白、mRNA表达及IL-1β水平均升高(P<0.01);与模型组比较,酮替芬组和足三里组大鼠十二指肠组织NGF、NTRK1蛋白、mRNA表达及IL-1β水平均降低(P<0.01,P<0.05);与酮替芬组比较,足三里组大鼠十二指肠组织NGF mRNA、NTRK1蛋白及mRNA表达均降低(P<0.05,P<0.01)。结论:电针“足三里”可能是通过抑制十二指肠肥大细胞活化,调节NGF及其受体表达,改善十二指肠低度炎性反应,从而对FD大鼠起到干预作用。.

Keywords: Point ST 36 (Zusanli); duodenum; electroacupuncture; functional dyspepsia (FD); mast cells; nerve growth factor (NGF); neurotrophic tyrosine kinase receptor type 1 (NTRK1).

MeSH terms

  • Acupuncture Points
  • Animals
  • Duodenum / metabolism
  • Dyspepsia* / genetics
  • Dyspepsia* / therapy
  • Electroacupuncture*
  • Ketotifen
  • Mast Cells / metabolism
  • Nerve Growth Factor / genetics
  • Nerve Growth Factor / metabolism
  • RNA, Messenger
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, trkA / genetics

Substances

  • RNA, Messenger
  • Nerve Growth Factor
  • Receptor, trkA
  • Ketotifen