基于"脑-肠-菌"轴探讨子午流注揿针改善慢传输型便秘大鼠肠道功能的作用机制OA

Objective To investigate the mechanism of meridian-flow intradermal needling on the intestinal transit function in rats with slow transit constipation(STC)based on the"Brain-Gut-Microbiota"axis theory.Methods Forty SPF-grade Wister rats,with an equal number of male and half female,were randomly assigned into a blank group(8 rats)and a modeling group(32 rats)using the random number table method.Rats in the modeling group were intragastrically administered 3 mg/kg loperamide hydro-chloride suspension daily for 14 consecutive days to establish the STC rat model by inhibiting intestinal peristalsis.Meanwhile,the blank group received an equal volume of normal saline by gavage.Rats with successful model establisment were randomly divided into a model group,a western medicine group,the common intradermal needle group,and the meridian-flow intradermal needling group,with eight rats in each group.During the intervention period,all groups except the blank group continued to receive loper-amide hydrochloride at the modeling dose to maintain a stable STC model,and the blank group was given an equal volume of normal saline simultaneously.The western medicine group was intragastrically administered prucalopride succinate at a dosage of 0.18 mg/(kg·d),with a volume of 1 mL per 100 g body weight,once daily.The common intradermal needle group received intrader-mal needling at bilateral Tianshu(ST25)and Dachangshu(BL25)acupoints at 10:00 AM every day.The meridian-flow intradermal needling group used the identical acupoints and procedures as the common intradermal needle group,but with time-specific interven-tion:Tianshu was needled at the Chen hour(08:00 AM)and Dachangshu at the Shen hour(16:00 PM)daily.Following 14 consecu-tive days of intervention,intestinal motility was evaluated by the number of fecal particles within 6 hours,fecal water content,and the small intestinal propulsion rate.The relative protein expression levels of 5-hydroxytryptamine(5-HT)and vasoactive intestinal peptide(VIP)in colon tissue and norepinephrine(NE)in brain tissue were detected by enzyme-linked immunosorbent assay(ELI-SA).Nitric oxide(NO)concentration in brain tissue was measured by the Griess chemical method.Intestinal microbiota alterations in fecal samples from the five groups were analyzed by 16S rRNA gene sequencing.The functional gene enrichment of intestinal microbiota in the meridian-flow intradermal needling group was analyzed using the Kyoto Encyclopedia of Genes and Genomes(KEGG)database.Results 1)Intestinal motility:Compared with the blank group,the model group showed fewer fecal particles within 6 hours(P<0.05),a lower fecal water content(P<0.05),and a lower small-intestinal propulsion rate(P<0.05).Compared with the model group,the western medicine group,the common intradermal needle group,and the meridian-flow intradermal needling group exhibited a greater number of fecal particles within 6 hours(P<0.05),a higher fecal water content(P<0.05),and a higher small intestinal propulsion rate(P<0.05).Compared with the common intradermal needle group,the western medicine group and the meridian-flow intradermal needling group exhibited a greater number of fecal particles within 6 hours(P<0.05),and a higher small intestinal propulsion rate(P<0.05).2)Brain-gut peptide levels:Compared with the blank group,the model group presented a lower protein expression levels of 5-HT and VIP in colon tissue(P<0.05),a higher protein expression of NE in brain tissue(P<0.05),and a higher NO concentration(P<0.05).Compared with the model group,the western medicine group,the common intradermal needle group,and the meridian-flow intradermal needling group showed a higher protein expressions of 5-HT and VIP in colon tissues(P<0.05),a lower protein expression of NE in brain tissues(P<0.05),and a lower NO concentration(P<0.05).Compared with the com-mon intradermal needle group,the western medicine group and the meridian-flow intradermal needling group had a higher protein expressions of 5-HT and VIP in colon tissue(P<0.05)and a lower NO concentration in brain tissue(P<0.05);the meridian-flow intradermal needling group also demonstrated a lower protein expression of NE in brain tissue(P<0.05).Compared with the western medicine group,the meridian-flow intradermal needling group displayed a higher protein expressions of 5-HT and VIP in colon tis-sue(P<0.05),a lower protein expression of NE in brain tissue(P<0.05),and a lower NO concentration(P<0.05).3)Intestinal micro-biota analysis:At the OTU level,the numbers of unique OTUs in the blank,model,western medicine,the common intradermal nee-dle,and the meridian-flow intradermal needling groups were 2,738,3,862,4,397,3,956,and 2,901,respectively,with 323 core OTUs shared by all five groups.α-diversity analysis revealed that compared with the blank group,the model group showed a de-creasing trend in species abundance and diversity of gut microbiota(P<0.05).Compared with the model group,the western medicine group,the common intradermal needle group,and the meridian-flow intradermal needling group exhibited an increasing trend in the abundance and diversity of intestinal microbiota(P<0.05),with the most significant increase in the meridian-flow intradermal nee-dling group(P<0.05).The β-diversity analysis demonstrated the greatest inter-sample distance between the model group and the me-ridian-flow intradermal needling group.Differential species analysis indicated that the model group was characterized by high abun-dance of Kineothrix,whereas the meridian-flow intradermal needling group exhibited a relatively high abundance of Klebsiella and specific enrichment of Prevotella,Bacteroides H,and other genera.The functional pathways of the intestinal microbiota in the merid-ian-flow intradermal needling group were mainly concentrated in metabolism-related pathways.Among these,the carbohydrate me-tabolism had the highest relative abundance,followed by amino acid metabolism,the metabolism of cofactors and vitamins,and the metabolism of terpenoids and polyketides.Conclusion The meridian-flow intradermal needling can promote the recovery of intes-tinal transit function in STC rats.Its mechanism may be related to the regulation of the"Brain-Gut-Microbiota"axis,thereby improv-ing intestinal motility,restoring the homeostasis of brain-gut peptides,and optimizing the structure and metabolism of the microbiota.