| Effects of individualized colonic electrical stimulation using different stimulation patterns on gastrointestinal transit time, defecation and food intake in a normal canine modelAim This study aimed to compare the effects of individualized colonic electrical stimulation (CES) on gastrointestinal transit time (GITT), energy consumption, stool frequency, stool consistency and food intake using different parameter selection patterns and stimulation sites in a normal canine model.Methods Eight beagle dogs underwent CES. The CES was conducted to determine the parameters with different pulse configurations, based on symptoms. Influences on energy consumption and GITT were compared between CES sessions with different pulse configurations. The GITT, stool frequency, stool consistency and food intake were observed and compared to assess the effects of CES at different stimulation sites.Results The individualized parameters of CES varied among the dogs. In proximal colon electrical stimulation (PCES) and rectosigmoid colon electrical stimulation (RCES), energy consumption was lower with the constant-pulse-width mode than with the constant-pulse-amplitude mode (P=0.012 and P=0.018, respectively). There was no statistical difference between the two pulse configurations in GITT assessment. Compared with sham CES session (28.6±4.6 h), the PCES (20.2±4.5 h), RCES (21.8± 4.0 h) and double-sites CES (21.5±3.4 h) sessions significantly accelerated GITT (all P＜0.001). There was no statistical difference in GITT between PCES, RCES and double-sites CES sessions. Compared with sham CES session (2.7±0.7 times/d), RCES (3.6±0.6 times/d) and double-sites CES (3.5±0.6 times/d) sessions exhibited significant higher stool frequency (P＜0.001 and P=0.001, respectively). The evaluation of the stool consistency with the Bristol scale showed no statistically significant difference among the four CES sessions. The PCES (179.4±46.4 g/d) and RCES (178.1±40.5 g/d) sessions significantly inhibited food intake compared with sham stimulation (211.1± 41.8 g/d) (P=0.003 and P=0.002, respectively).Conclusions Constant-pulse-width mode is an appropriate pulse configuration for individualized CES. At different stimulation sites, the CES exert different effects on stool frequency and food intake. Double-sites CES may be an ideal method.Improvement of double-sites individualized colonic electrical stimulation on gastrointestinal transit and defecation in a canine constipation model and its mechanismsAim This study aimed to evaluate the effects of double-sites CES on gastrointestinal transit and defecation, and explore its mechanisms in a canine model of slow transit constipation (STC).Methods Parameters were individualized according to the symptoms of the stimulated dogs with the constant-pulse-width mode. In the STC model, the GITT, colonic transit time (CTT), stool frequency and stool consistency were assessed to evaluate the effects of double-site CES, and of double-site CES combined with atropine or N-nitro-L-arginine (L-NNA).Results Individualized parameters varied among the animals in the constant-pulse-width mode. The double-sites CES significantly shortened GITT (30.8±2.3 h vs 41.5±4.6 h, P=0.001) and CTT (11.6±2.5 h vs 19.5±3.0 h, P＜0.001) compared with sham CES. Compared with sham CES, the CES also exhibited significantly higher stool frequency (3.0±0.8 times/d vs 2.2±0.4 times/d, P=0.018) and stool consistency score (3.8±0.2 vs 3.2±0.3, P=0.001). Co-treatment with atropine or L-NNA blocked the effects of CES on GITT, CTT and stool consistency. The stool frequency increased by CES, however, only reduced by co-treatment with L-NNA.Conclusions This double-site CES can improve the gastrointestinal transit and defecation in a canine STC model, possibly by activating the cholinergic and nitrergic pathways. The CES mode used in this study may be proved effective in treating STC.Comparison of the effects of the colonic electrical stimulation and prucalopride on gastrointestinal transit and defecation in a canine constipation modelAim This study aimed to compare the effects of CES and prucalopride on gastrointestinal transit and defecation in a canine constipation model, and evaluate the histocompatibility of the CES device.Methods Eight beagle dogs underwent the experiment. Parameters were individualized according to the symptoms of the stimulated dogs. In the STC model, short-term effects on GITT, CTT, stool frequency and stool consistency were compared between CES session and prucalopride session. The histocompatibility of the implantable device was evaluated ten months after implant surgery.Results The individualized parameters of CES varied among the dogs. Compared with sham CES session (44.9±4.9 h), GITT were not significantly shortened by CES session (37.4±3.4 h) and prucalopride session (38.4±8.1 h) (P=0.081 and P=0.151, respectively). The CES (15.6±3.1 h) and prucalopride (16.3±3.9 h) treatment significantly accelerated CTT compared with sham stimulation (21.3±2.2 h) (P=0.012 and P=0.026, respectively). Compared with sham CES session (2.9±0.2), CES session (3.7±0.3) and prucalopride session (3.7±0.2) exhibited significant higher stool consistency scores (all P＜0.001). There was no statistical difference in GITT, CTT and stool consistency scores between CES session and prucalopride session. Compared with sham CES session, CES session exhibited significant higher stool frequency (2.1±0.2 times/d vs 3.0±0.4 times/d, P=0.003), and prucalopride session (2.6±0.5 times/d) did not significantly chang the stool frequency (P=0.110). No severe inflammation response was detected in the gross and microscopic appearance, and there was an ideal histocompatibility about the CES device.Conclusions The CES and prucalopride treatment may possess similar short-term effects on the improvements of colonic transit and stool consistency, and the CES outperformed prucalopride treatment in defecation inducement in the short term. There were ideal endurance and histocompatibility to the animals underwent CES. |
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