Preliminary Study On The Relationship Between The Changes Of Intestinal Flora And Immune Response In Mice Infected With Trichinella Spiralis

Trichinella spiralis belongs to Nemathelminthes,Aphasmida or Adenophorea,Enoplida.Trichinosis is a globally distributed zoonotic disease which is highly harmful to human health and animal husbandry production.With the deepening of research,T.Spiralis related research has not only confined to the pathogenicity of T.spiralis and the prevention and treatment of T.spiralis,the immune mechanism about T.spiralis such as immune escaping are catching more and more attention.In recent years,many studies have noted the changes and effects of intestinal flora in the development and progression of immune,nutritional metabolism and diseases(such as metabolic syndrome,colorectal cancer,liver cancer,diabetes,etc.),but study of changes of intestinal flora during parasitic infections is still not plentiful.In this study,we focused on the alteration of intestinal flora during T.spiralis infection using Illumina high-throughput sequencing to explore intestinal flora in mice before and after infection and at different infection periods;using flow cytometry and ELISA detection methods to discuss the changes of immune related indexes.We hoped to provide new ideas to the treatment and research of parasitic disease and intestinal disease.The specific contents and results are as follows:(1)T.spiralis infection effect on intestinal flora of BALB/c mice: 24 female SPF BALB/c mice were divided into two groups,each group of 12,a group was T.spiralis group,another group was PBS group.Experimental group mice each received intragastric administration of 300 muscle larvae of T.spiralis,and PBS group mice each received equal volume of PBS.Collected fresh feces at 7 days,14 days,21 days and 28 days after infection each under sterile conditions.Extracted bacterial genomic DNA in feces,then quantitated,mixed and sequenced 16 SrRNA gene sequences of Vl-V3 total DNA hypervariable region amplification PCR product.Sequence analysis showed that the OUT of intestinal flora of mice after T.spiralis infection at 7 days,14 days,21 days,28 days were all higher than that of the control group.All sequences belong to the following four strains,namely: Bacteroidetes,Firmicutes,Proteobacteria and Deferribacteres,the proportion are more than 99%.The number of bacteroidetes in the intestinal mucosa of the mice was significantly higher than that of the control group at 7 days,14 days,21 days and 28 days,and the difference was significant(P <0.01)at 7 days(P <0.01).At the same time,the number of firmicutes in the experimental group was significantly lower than that in the control group at 7days(P <0.01).The infection rate of T.spiralis was 28 days The number was slightly higher than the control group,the difference was not significant.The number of proteobacteria in the experimental group was lower than that in the control group at 7 days,14 days,21 days and 28days(P <0.05).The number of intestinal deferribacteres in the experimental group was significantly higher than that in the control group(P <0.05),at 14 days,21 days and 28 days,(P<0.05),the difference between the two groups was significant(P <0.05).(2)Impact of T.spiralis on BALB/c mice: We used flow cytometry to examine the number of mesenteric lymph nodes(MLN)of Foxp3 Treg changes situation;and the Th2 type cytokine IL-10,and Th17 cytokine IL-17 expression volume of changes situation;and we used indirect ELISA method to detect expression volume of mice serum of IFN-?,IL-4,IL-22 and IL-17 which is from different infection period of T.spiralis.The results showed that the secretory volume of Th2 cytokine was always higher than that of the control group during the infection of T.spiralis;and the secretory volume of Th1 was lower than that of the control group;and the number of Treg was always higher than that of the control group;the secretory volume of Th17 cytokines was higher than that of the control group in the early stage of T.spiralis infection,late stage of infection was flat with the control group.The level of secretory volume of Th1,Th2,Th17 cytokines gradually tended to be moderate with the extension of T.spiralis infection time.The above results provide a reference for the association between parasitic infection and intestinal flora,and provide a new direction for the treatment of intestinal parasitic diseases and basic treatment of intestinal disease.