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Study 35 of 35VIP (Vasoactive Intestinal Polypeptide) literatureChinese journal of integrative medicine · Observational2026

Liangfu Pill Alleviates Constipation-Predominant Irritable Bowel Syndrome through Modulation of 5-HT Signaling Pathway and Gut Microbiota.

LFP appears to improve certain symptoms of IBS-C in rat models, potentially through modulation of serotonin signaling and gut microbiota.

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Where it sits

this study against the rest of the vip (vasoactive intestinal polypeptide) corpus
7
Preclinical
22
Observational · this one
0
Open-label
2
Randomised
4
Reviews

Summary and findings

This study investigated the effects of Liangfu Pill (LFP) on serotonin signaling and gut microbiota in constipation-predominant irritable bowel syndrome (IBS-C) rat models. The study involved 60 SD rats divided into various treatment groups over a 7-day intervention period. The findings indicated that LFP increased levels of vasoactive intestinal peptide (VIP) and improved fecal count and stool scores.

How much of this paper we could read: full text read (0.70). We had a clear abstract, so the summary below closely tracks the paper. What this means →
P<0.05 or P<0.01 for various measured outcomes.2026

Abstract

The authors’ words, as Chinese journal of integrative medicine supplied them

<h4>Objective</h4>To elucidate the modulation mechanism of Liangfu Pill (LFP) on serotonin (5-HT) signaling pathway and gut microbiota in constipation-predominant irritable bowel syndrome (IBS-C) rat models to clarify its therapeutic effects.<h4>Methods</h4>The major metabolites of LFP were analyzed, and network analysis was used to predict the potential mechanism of LFP on IBS-C. Sixty SD rats were allocated to normal, normal + LFP (N+LFP), model, moxapride, low- and high-dose LFP (LFP-L and LFP-H) groups. IBS-C model was developed by tail-clamping stress, irregular feeding, and ice-water gavage for 14 d. Following 7-d intervention, levels of substance P (SP), vasoactive intestinal peptide (VIP), and melatonin (MLT) in the colon tissues were quantified using ELISA, while high-performance liquid chromatography was used to measure the concentration of 5-HT in colon tissue. The expressions of serotonin transporter (SERT), tryptophan hydroxylase 1 (TPH1), and serotonin 4 receptor (5-HT<sub>4</sub>R) proteins were assessed using Western blot. The open-field test was performed on day 14 and day 21 to evaluate rats' locomotor activity. Additionally, the structure of rat intestinal microbiota was analyzed by 16S rDNA high-throughput sequencing technology.<h4>Results</h4>Chromatographic analysis identified 104 major metabolites in LFP. Network analysis predicted that the main signaling pathways involved serotonergic synapses and regulation of transient receptor potential channels by inflammatory mediators. In rats with IBS-C, LFP increased body weight gain, open-field total distance and average speed, fecal count, Bristol stool score, and the levels of SP and VIP, while decreasing abdominal withdrawal reflex scores and 5-HT level (P<0.05 or P<0.01). The protein expressions of SERT and 5-HT<sub>4</sub>R were upregulated (P<0.05 or P<0.01), whereas TPH1 expression was downregulated (P<0.01). Additionally, LFP improved gut microbiota composition, with increased Chao, abundance-based coverage estimator, Shannon indices (P<0.05 or P<0.01) and relative abundance of differential microbial taxa.<h4>Conclusions</h4>LFP alleviates IBS-C symptoms, improves overall condition and especially reduces visceral sensitivity in rats. The potential mechanism may involve modulation of 5-HT signaling pathway and gut microbiota.

Background

Not reported in abstract.

Methods

Not reported in abstract.

Results

Not reported in abstract.

Interpretation

Not reported in abstract.

Limitations

Not reported in abstract.

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