Mechanisms of Regulatory Role of Porcine Limosilactobacillus mucosae and Tryptophan on Gastrointestinal Immune Homeostasis and Function Development of Young Mice
The aim of this experiment was to investigate the regulation and mechanism of the gastrointestinal 5-hydroxytryptamine receptor(HTR)and immune function development of young mice treated with Limosilacto-bacillus mucosae and tryptophan alone or in combination.Thirty-two 3-week-old male C57BL/6 mice were randomly divided into control group,tryptophan group,Limosilactobacillus mucosae group and Limosilactoba-cillus mucosae+tryptophan group with 8 replicates per group and 1 mouse per replicate.Mice in Limosilactoba-cillus mucosae group and Limosilactobacillus mucosae+tryptophan group were given 100 μL/(mouse·d)Li-mosilactobacillus mucosae live bacterial suspension(1×108 CFU/mL)every other day,and those in the other groups were given the same amount of phosphate buffer solution;while mice in the tryptophan group and Li-mosilactobacillus mucosae+tryptophan group were added 0.15 mg/(g BW·d)tryptophan in drinking water(0.5 mg/mL tryptophan in drinking water),and 0.44 mg/mL alanine was added in drinking water of the other groups as iso-nitrogen treatment.The experiment lasted for 14 days.The results showed as follows:1)after 2 weeks of treatment with Limosilactobacillus mucosae and tryptophan,the body weight and small intestine length of mice were significantly increased(P＜0.05);2)Limosilactobacillus mucosae or combined with tryp-tophan could regulate the metabolic homeostasis of 5-hydroxytryptamine(5-HT)in gastrointestinal tract,dif-ferentiated the expression of HTR in gastrointestinal tract,and significantly up-regulated the expression of HTR4 and HTR7 in the stomach(P＜0.05);3)Limosilactobacillus mucosae or combined with tryptophan could pro-mote the polarization of M2-type macrophages in stomach and jejunum,up-regulate the expression of Wnt3a,and differentially regulate the expression of transforming growth factor-β(TGF-β)subtypes in gastrointestinal tract;4)Limosilactobacillus mucosae or combined with tryptophan significantly increased the indole concentra-tion in colon(P＜0.05),but significantly decreased the 5-HT concentration in small intestine and colon(P＜0.05).These results indicate that the combination of porcine Limosilactobacillus mucosae and tryptophan can promote gastrointestinal development and growth of young mice by regulating gastrointestinal 5-HT metabolism and HTR expression,up-regulating M2-type macrophage polarization and gastrointestinal TGF-β subtype ex-pression,and activating Wnt signaling.[Chinese Journal of Animal Nutrition,2024,36(9):6015-6026]
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维普
