OBJECTIVE To evaluate the efficacy and mechanism of Kai-Xin-San in improving intestinal function damage in-duced by intragastric administration of fluoxetine in chronic unpredictable mild stress(CUMS)depression model mice.METHODS A CUMS depression mouse model was established and treated with fluoxetine(9 mg·kg-1·d-1),low-dose(1.5 g·kg-1·d-1)and high-dose(4.5 g·kg-1·d-1)Kai-Xin-San,fluoxetine combined with low-dose(9 mg·kg-1·d-1+1.5 g·kg-1·d-1)and high-dose(9 mg·kg-1·d-1+4.5 g·kg-1·d-1)Kai-Xin-San,and mosapride combined with fluoxetine(2 mg·kg-1·d-1+9 mg·kg-1·d-1)for 28 consecutive days.The body weight of mice was measured;the food utilization was calculated and the serum D-xylose content was measured to evaluate the intestinal mucosal absorption capacity of mice;HE staining was used to evaluate the intestinal structural dam-age of mice;TUNEL staining was used to evaluate the intestinal tissue apoptosis of mice;ELISA was used to detect the expression lev-els of brain gut peptides such as vasoactive intestinal peptide(VIP),gastrin(MTL),substance P(SP)and Ghrelin in the intestine of mice;Western blot was used to detect the expression of apoptosis signaling pathway proteins.RESULTS Compared with the model group,fluoxetine significantly reduced the body weight of mice after 2 weeks of administration(P<0.05);the food utilization and ser-um D-xylose content of mice were significantly reduced after 4 weeks of administration(P<0.05),and the intestinal villi of depressed mice were damaged(P<0.05)and intestinal epithelial apoptosis of mice was enhanced(P<0.01);the expression of VIP in the small intestine of mice was upregulated(P<0.05),and the expression of MTL,SP and Ghrelin was downregulated(P<0.05,P<0.01);cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9 in the intestinal apoptosis signaling pathway of mice were upregulat-ed(P<0.05,P<0.01).Compared with the fluoxetine group,the body weight of mice was significantly increased after 2 weeks of com-bined use of Kai-Xin-San and fluoxetine(P<0.05,P<0.01).After 4 weeks of combined use of high-dose Kai-Xin-San and fluoxe-tine,the food utilization and serum D-xylose expression of mice were significantly increased(P<0.05);intestinal villus damage was improved(P<0.05);intestinal epithelial tissue apoptosis was significantly reduced(P<0.01);small intestinal VIP expression was significantly downregulated(P<0.01),and the expression of MTL,SP and Ghrelin was significantly upregulated(P<0.05);cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9 in the apoptosis signaling pathway were significantly reduced(P<0.05,P<0.01).CONCLUSION Kai-Xin-San has the effect of improving the gastrointestinal motility and intestinal absorption function dam-age caused by fluoxetine in depressed mice.Its mechanism may be related to improving the expression of brain gut peptide in the small intestine and inhibiting intestinal villi damage and intestinal tissue apoptosis.

OBJECTIVE To evaluate the efficacy and mechanism of Kai-Xin-San in improving intestinal function damage in-duced by intragastric administration of fluoxetine in chronic unpredictable mild stress(CUMS)depression model mice.METHODS A CUMS depression mouse model was established and treated with fluoxetine(9 mg·kg-1·d-1),low-dose(1.5 g·kg-1·d-1)and high-dose(4.5 g·kg-1·d-1)Kai-Xin-San,fluoxetine combined with low-dose(9 mg·kg-1·d-1+1.5 g·kg-1·d-1)and high-dose(9 mg·kg-1·d-1+4.5 g·kg-1·d-1)Kai-Xin-San,and mosapride combined with fluoxetine(2 mg·kg-1·d-1+9 mg·kg-1·d-1)for 28 consecutive days.The body weight of mice was measured;the food utilization was calculated and the serum D-xylose content was measured to evaluate the intestinal mucosal absorption capacity of mice;HE staining was used to evaluate the intestinal structural dam-age of mice;TUNEL staining was used to evaluate the intestinal tissue apoptosis of mice;ELISA was used to detect the expression lev-els of brain gut peptides such as vasoactive intestinal peptide(VIP),gastrin(MTL),substance P(SP)and Ghrelin in the intestine of mice;Western blot was used to detect the expression of apoptosis signaling pathway proteins.RESULTS Compared with the model group,fluoxetine significantly reduced the body weight of mice after 2 weeks of administration(P<0.05);the food utilization and ser-um D-xylose content of mice were significantly reduced after 4 weeks of administration(P<0.05),and the intestinal villi of depressed mice were damaged(P<0.05)and intestinal epithelial apoptosis of mice was enhanced(P<0.01);the expression of VIP in the small intestine of mice was upregulated(P<0.05),and the expression of MTL,SP and Ghrelin was downregulated(P<0.05,P<0.01);cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9 in the intestinal apoptosis signaling pathway of mice were upregulat-ed(P<0.05,P<0.01).Compared with the fluoxetine group,the body weight of mice was significantly increased after 2 weeks of com-bined use of Kai-Xin-San and fluoxetine(P<0.05,P<0.01).After 4 weeks of combined use of high-dose Kai-Xin-San and fluoxe-tine,the food utilization and serum D-xylose expression of mice were significantly increased(P<0.05);intestinal villus damage was improved(P<0.05);intestinal epithelial tissue apoptosis was significantly reduced(P<0.01);small intestinal VIP expression was significantly downregulated(P<0.01),and the expression of MTL,SP and Ghrelin was significantly upregulated(P<0.05);cleaved Caspase-3/Caspase-3 and cleaved Caspase-9/Caspase-9 in the apoptosis signaling pathway were significantly reduced(P<0.05,P<0.01).CONCLUSION Kai-Xin-San has the effect of improving the gastrointestinal motility and intestinal absorption function dam-age caused by fluoxetine in depressed mice.Its mechanism may be related to improving the expression of brain gut peptide in the small intestine and inhibiting intestinal villi damage and intestinal tissue apoptosis.

OBJECTIVE To determine the effect of Kai-Xin-San(KXS)combined with fluoxetine on the intestinal flora and the expression of inflammatory factors in chronic unpredictable mild stress(CUMS)depression mice and to elucidate the antidepressant mechanism of regulating"intestine-brain"axis.METHODS CUMS depression mice model was established and the effect of com-bined medication on improving depression-like behaviors of mice was evaluated by determination of sucrose preference rate,immobile time of tail suspension and forced swimming.Additionally,the levels of inflammatory factors IL-6,IL-1β,TNF-α and LPS were de-termined in cortex,serum and intestine using the ELISA method.The composition of intestinal flora in mouse feces was analyzed by 16S rRNA sequence sequencing.Furthermore,Western blot assay was utilized to determine the expression levels of intestinal barrier proteins such as ZO-1,Occludin and Claudin-5.RESULTS The combination of KXS and fluoxetine resulted in a significant in-crease in sucrose preference rate(P<0.01)and decreased immobile time of tail suspension and forced swimming(P<0.05,P<0.01)in CUMS mice.The antidepressant effect of KXS combined with middle dose of fluoxetine was equivalent to that of high dose of fluoxe-tine alone.Meanwhile,the combination could significantly inhibit the up-regulation of inflammatory factors in the cortex,serum and small intestine of model animals(P<0.05,P<0.01).Intestinal flora analysis showed that the combination could improve the ratio of Gram-positive bacteria to negative bacteria in the intestinal tract of model animals,and the improvement of the relative abundance of intestinal bacteria Lachnospiraceae,Bifidobacterium,Ruminococcus,Blautia,Eubacterium,Intestinimonas,Erysipelotrichaceae,Alis-tipes,Desulfovibrionia and Coriobacteriaceae UCG-002 and so on in the model animals was significantly related to the alleviation of de-pression-like behavior and the down-regulation of cortical inflammatory factors(P<0.05,P<0.01).Furthermore,the combination treatment could significantly up-regulate the expression of intestinal barrier protein(P<0.01).CONCLUSION KXS combined with fluoxetine can alleviate depression-like behavior and reduce fluoxetine dosage in CUMS model animals.The combination of the two drugs may regulate the composition of intestinal flora,inhibit the expression of intestinal inflammatory factors,up-regulate intestinal barrier proteins,and thus reduce the expression of serum and central inflammatory factors,which may be the mechanism of their regu-lation of the gut brain axis in antidepressant action.