| Gut microbial diversity and structural composition are closely related to the occurrence of allergic diseases and it is great significance to explore the influencing factors of intestinal microbes.The hygiene hypothesis indicates that low environmental cleanliness(e.g.farms)has a significant protective effect on allergic diseases.Our previous study found that mice living in low cleanliness environment had higher intestinal micro-ecological richness and diversity,and found that only increasing microbes in the environment had little effect on intestinal microbes in mice,while increasing soil in the environment had a significant effect on intestinal microbial structure composition in mice.Soil is rich in microorganisms,the species of which is about 10 times the type of intestinal microbes,known as the "microbial germplasm bank ".What ways does the soil in the environment affect the structural composition of intestinal microbes is the problem to be solved in this study.The soil in the environment can further affect the gut microbiota by affecting the mouse skin microbiota.It has been found that the microbial structure of dogs living in different cleanliness environments is quite different.Soil in the environment can also affect the gut microbiota by feeding into the body.Soil maybe also affect gut microbes simultaneously through two pathways.Intestinal microecology is closely related to immune system diseases and it is great significance to explore the influencing factors of intestinal microecology.Previous studies of our group found that exposure to lower environment cleanliness increases gut microbial diversity of mouse.To explore this issue 38 mice with consistent sources were divided into four groups in this study: high-definition environmental control group(SPF),low-clean environmental control group(Farm),fed high-pressure sterilized soil group(SS),and drinking environmental microbial group(MW).At the same time,we also used the DNFB eczema model to verify the correlation between intestinal microbiota and immunity in mice.Experiment content: 38 C57 mice of the same 7 weeks old SPF grade were randomly divided into four groups(SPF,Farm,MW and SS).The mouse had the same age,litter,sex delivery mode and pre-feeding conditions.SPF,SS and MW group continued to be kept in SPF animal houses1;Farm group were kept in the SPF animal house2.SPF group added sterile bedding and fed normal feed and drinking water.SS group added sterile bedding and fed sterilized soil and common feed mixture.MW group added sterile bedding and drank the water of microorganisms isolated from the environment.Farm group bedding mixed 1/3soil and the mouse fed normal water and food.Four groups of mice were fed water and food once a week.After 42 days of treatment,mouse feces were collected and 16 S r RNA sequencing and macrogenome sequencing were performed for gut microbial structure composition analysis.On day 43,we began to use 2-4-dinitrofluorobenzene(2,4-dinitrofluorobenzene,DNFB)for allergic skin irritation in mice,and measured the protective function of intestinal microorganism in each group by serum total Ig E detection and skin lesion degree analysis.Results:(1)The diversity and richness of intestinal microbes in farm house group(Farm)and sterile soil group(SS)mice were significantly higher than those in drinking microbe water group(MW)and Clean environment group(SPF).(2)The gut microbial ?diversity of SS group were more similar to Farm group,while MW and SPF were more similar.(3)The results of macrogenome sequencing showed that SS group contained more type VI secretion system coding genes,Farm mice contained more type III secretion system coding genes.(4)DNFB treatment results showed that immunity of SS and Farm mice improved significantly.Conclusion: Feeding into the soil is a way to influence the gut microbial structure of mice.This study also further verified that the simple increase of microbial content in the environment had little effect on the diversity of intestinal microecology. |
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