Study On The Preventive Effect Of Lactobacillus Rhamnosus Zz On Intestinal Microecological Changes And Depression-like Symptoms Of Mice Induced By CUMS

The total number of patients suffering from depression globally exceeds 300 million.It is a multi-cause mental disorder that seriously threatens people's lives and public health.It is also the disease with the highest suicide rate and disability rate.The current clinical treatment is challenging to consider the complex and diverse pathogenesis of depression with multiple systems and multiple aspects,and it is accompanied by disadvantages such as significant side effects,high recurrence rate,long treatment process,and narrow scope of application.Based on the increase in public health awareness,people have found that disease prevention is more important than treatment,and more people want to prevent depression and other neuropsychiatric diseases by improving their lifestyles and adjusting their diet.It is known that probiotics can improve depression by non-drug treatment.At the same time,Lactobacillus rhamnosus is a kind of probiotic that has robust functionality,high safety,and allowed to be added to food.In this study,Lactobacillus rhamnosus zz was selected as an intervention to explore the effects and specific mechanisms of preventive supplementation of probiotics on depression-like behaviors,intestinal microecological damage,and physiological and biochemical changes in the process of depression.They were laying a theoretical foundation for the occurrence of depression and assisting other treatments to improve depression.In this study,4-week-old SPF-grade C57BL/6J male mice were used as the research object.The chronic unpredictable mild stress(CUMS)continuous induction model was used for five weeks to simulate the onset of depression in humans.The blank control group and the CUMS model group of mice Gavage with normal saline.The intervention group mice were gavage with high,medium,and low concentrations of 1×10~9 CFU/kg/d,1×10~8 CFU/kg/d,and 1×10~7 CFU/kg/d Lactobacillus rhamnosus zz bacteria.To explore the preventive effect and mechanism of Lactobacillus rhamnosus zz intervention on CUMS-induced depression in mice from the aspects of behavior,intestinal flora,intestinal function,physiology,and biochemistry.The results show that the effect of Lactobacillus rhamnosus zz has a dose effect,and the higher the concentration,the better the effect.Mice stimulated by CUMS under the action of Lactobacillus rhamnosus zz,the body weight development is improved,the sugar water preference is restored,the immobility time is reduced in the forced swimming and tail suspension test,the total moving distance and the center area stay in the open field test Increase in time;impedance changes in the intestinal flora of mice induced by CUMS,increase the abundance of Firmicutes,down-regulate the abundance of Bacteroidetes and Actinobacteria at the phylum level,At the genus level,the relative abundance of Lachnospiraceae NK4A136 group in Lachnospiraceae,Lactobacillus and Roseburia was up-regulated,and the relative abundance of Bacteroides and Muribaculum was down-regulated;intestinal tissue The level of IL-2,IL-6,TNF-?is reduced,the secretion of IL-10 and Ig A is increased,the level of secretion of IL-10 and Ig A is increased,the intestinal inflammation is reduced,the intestinal immunity is improved,and the intestinal health is maintained;further research found that Lactobacillus rhamnosus zz can also effectively resist the depression-like physiological changes in mice induced by CUMS,restore the levels of monoamine neurotransmitters such as 5-HT,NE,DA in the synaptic cleft,reduce the abnormal secretion of ACTH and CORT in the HPA axis,and inhibit Microglia in the hippocampus area positively express IBA-1,and up-regulate the content of BDNF and Trk B in the hippocampus to play its role in preventing depression.In summary,it is found that Lactobacillus rhamnosus zz can improve CUMS-induced depression-like behavior in mice,resist CUMS-induced changes in the intestinal flora of mice,improve intestinal health,and restore depression-like physiological and biochemical symptoms.It has the ability to prevent strain with the potential for the development of depression.