Intestinal Microbial Diversity During Early-Life Colonization Shapes Th1/Th2 Balance On Asthma Model In Mice

[Objective] The aim of this study was to investigate the effect of early different microbial exposures on mice intestinal microflora colonization[method] 24 adult SPF (SPF) BALB/c mice 24(male:8, female:16), male and female 2:1 caged, after conception,parents and Offsprings are divided into periods (fetal period, lactation, childhood), and reared in different environments.Group A:Offsprings were kept in SPF laboratory animal environmental facilities during fetal period, lactation, childhood;group.B:Offsprings were kept in SPF environment during fetal period, lactation, and kept in general environment during childhood, group.C:Offsprings were kept in SPF environment during fetal period, and were kept in the general environment during lactation, childhood, group D:Offsprings were kept in general environment during fetal period, lactation, childhood; and feces samples were collected in each different period (three days after birth,three weeks after birth, five weeks after birth)of mice After bacterial DNAs were extracted from the feces samples and examined by PCR of 16S rDNA V3 Region, bacterial community profilings were obtained by the use of denaturing gradient gel electrophoresis(DGGE).Mice were housed in different environments to 6 weeks after the beginning of the establishment of an animal model of asthma, asthma-related detect cytokines IL-4,IFN-? Quantity One and Biodap softwares were used to analyze diversity and similarity differences of intestinal microbial community structures between each period of four groups.[result] 1.Comparison of intestinal flora of each group at different period:(1)Comparison of intestinal flora at three days after birth:The Stripe number(S'), Shannon-Weaver Diversity Index(H')and Simpson index(D') of intestinal microflora in group D were significantly higher than those of group A,group B and group C(P< 0.05). These indicators were no statistical significance on pairwise comparison among group A,group B and group C.(2)Comparison of intestinal flora at three weeks after birth:The Stripe number(S') and Shannon-Weaver Diversity Index(H') of intestinal microflora in group D were significantly higher than those of group A,group B and group C(P< 0.05).The Stripe number(S'), Shannon-Weaver Diversity Index(H')and Simpson index(D') of intestinal microflora in group C were significantly higher than those of group A and group B(P< 0.05).These indicators were no statistical significance on comparison between group A and group B.(3)Comparison of intestinal flora at five weeks after birth:The Stripe number(S'), Shannon-Weaver Diversity Index(H')and Simpson index(D') of intestinal microflora in group D were significantly higher than those of group A,group B.(P< 0.05). These indicators were no statistical significance on comparison between group D and group C.The Stripe number(S'), Shannon-Weaver Diversity Index(H'), Pielou Index (E) and Simpson index(D') of intestinal microflora in group C were significantly higher than those of group A and group B(P< 0.05).These indicators were no statistical significance on comparison between group A and group B.2. Influence on airway inflammation of asthma model in different environments:(1) Serum IL-4 content increased significantly (P<0.05) in asthma model mouse,while serum IFN-? and IFN-?/IL-4 decreased compared to control group of each group (P<0.05).(2) Comparison of mean value of serum IL-4 in asthma model of four groups:group A>group B>group C<group D,while serum IL-4 on pairwise comparison of each group was no statistical significance.Comparison of mean value of serum IFN-? in asthma model of four groups:group A<group B<group C<group D,and serum IFN-? in group D were significantly higher than group A (P<0.05). Comparison of mean value of IFN-?/IL-4 in asthma model of four groups:group A<group B<group C<group D,and the value of IFN-?/IL-4in group D was significantly higher than group A (P<0.05).(3) Comparison of mean value of serum IL-4 in normal control of four groups:group A>group B>group C>group D,while serum IL-4 on pairwise comparison of each group was no statistical significance.Comparison of mean value of serum IFN-? in asthma model of four groups:group A<group B<group C<group D,and serum IFN-? in group D were significantly higher than group A (P<0.05). Comparison of mean value of IFN-?/IL-4 in asthma model of four groups:group A<group B<group C<group D,while serum IFN-?/IL-4 on pairwise comparison of each group was no statistical significance.[Conclusion] (1)Exposure to different living environment in early life produce a clear impact on the intestinal microflora in early life. Intestinal microbial diversity tends to be increased exposed to a wider range of living environmental microbes. Mice will have more diverse intestinal flora when exposed to more diverse microbes living environment during fetal period and lactation.While diverse showed no significant effect on the intestinal flora when changed living environment during childhood.(2)the diversity of the intestinal flora colonization in Early life can affect immune function in adult, Which tends to induce ThO to Thl direction and improve the Th1/Th2 balance, reduce the airway inflammation of asthma.