Effects of electroacupuncture on the intestinal motility and local inflammation are modulated by acupoint selection and stimulation frequency in postoperative ileus mice.

Abstract

Electroacupuncture (EA) is widely used in various gastrointestinal diseases around the world, including POI. Here, we investigated different therapeutic effects of EA using lower limb and abdomen acupoints. Intestinal manipulation was performed in 88 mice, and eight mice underwent a sham operation. Forty mice were randomly divided into model group and four EA groups receiving stimulation at ST36 (2, 10, 30, 100Hz). The most effective frequency was then used in the following experiments. Forty-eight mice were randomly divided into six groups receiving EA treatment at ST37, ST39, ST25, CV4, CV12, and a non-acupuncture point. Gastrointestinal motility and plasma TNF-α, IL-6 were evaluated in all mice. The local immune response and α-smooth muscle actin (α-SMA) expression were assessed by immunofluorescence, ELISA, and HE staining. ST36 stimulated with 10 or 30Hz EA significantly increased the gastrointestinal motility and attenuated peripheral inflammation; however, ST36 stimulated with 2 or 100Hz did not induce any effect. The therapeutic effects on motility and inflammation of 10Hz EA in the ST36 group were similar in the ST36, ST37, ST39, or CV4 groups, but when applied to ST25, CV12 or non-acupoint had no significant differences. EA at ST36, ST37, ST39, or CV4 significantly inhibited local MPO activity, immune cells infiltration, and increased α-SMA. EA at lower limb and abdomen acupoints with the same stimulation parameters had different therapeutic effects on postoperative dysmotility and inflammation. Furthermore, EA protected SMC to improve gastrointestinal transit by reducing local inflammation in the intestinal musculature in POI.