| Objective:To explore the effect of prophylactic application of Lactobacillus returi DSM 17938 on intestinal flora in rats exposed to antibiotics in the early life.Method:A total of 36 newborn SD rats were randomly divided into 3 groups(n=12,respectively):the antibiotic exposure group(Group A),the probiotic intervention group(Group B)and the control group(Group C).From the postnatal day 2(PND2)to PND6:The rats in the group A were given ceftriaxone by gavage(0.5mg/g,once a day,the gavage volume was 0.3ml),2 hours after which the rats were given normal saline by gavage(0.3ml,once a day).The rats in the group B were given ceftriaxone by gavage(0.5mg/g,once a day,the gavage volume is 0.3ml),2 hours after which the rats were given Lactobacillus returi(LR)DSM 17938 by gavage(1×10~6 CFU/g,once a day,the gavage volume is 0.3ml).The rats in group C were given normal saline by gavage twice a day(the gavage volume is 0.3ml).On PND7 and PND42,the rats were killed in each group(n=6,respectively).Their jejunal and colonic mucosa and the intestinal content were collected for next-generation sequencing(the V4 region of 16S rDNA).On PND42,jejunal and colonic tissues were collected from rats for observing the pathological change in intestinal mucosas under a microscope.The length of intestinal villi and crypt depth were measured using Image Pro Plus 6.0.The data obtained in next-generation sequencing(the V4 region of 16S rDNA)were processed and drawn using QIIME and R software.SPSS 24.0 software package was used in the other statistical analysis,?=0.05 was considered significant.Result:On PND7 and PND21,the body weight of rats in the group A and B was significantly lower than that in the group C.On PND42,the body weight of rats in the group A was significantly lower than that in the group B and C(P<0.05).No significant inflammatory changes and other pathological changes were detected in the jejunum and colon of rats among the 3 groups.There was no significant difference were found in the jejunal and colonic mucosal villi or crypt depth among the 3groups(P>0.05).On PND7,the Alpha diversity and Beta diversity of jejunal flora showed no statistically significant difference,and the distribution of jejunal flora at phylum and genus levels also presented no statistically significant differences among the 3 groups(P>0.05).On PND42,compared with the group A,the Alpha diversity indexes of jejunal flora including sobs,chao and shannon indexs were decreased significantly while the simpson index was increased significantly in the group B.On PND42,the Beta diversity of jejunal flora in the group B was significantly different from that in the group A,the proportion of Firmicutes was increased while the proportion of Bacteroidetes,Euryarchaeota,Tenericutes and Proteobacteria was decreased in the group B's jejunal at phylum level,the proportion of Lactococcus,Ruminococcus,Dechloromonas and Dorea was decreased in group B's jejunal flora at genus level(P<0.05).On PND42,The Alpha diversity and Beta diversity of jejunal flora and floral distribution had no statistically significant differences between the group B and C(P>0.05).On PND7,compared with the group C,the Alpha diversity indexs of colonic flora including sobs,chao,ace indexs in the group A and B were significantly increased,the Beta diversity of colonic flora in the group A and B were significantly different from that in the group C,the proportion of Proteobacteria was increased while the proportion of Firmicutes was decreased in the group A and B's colonic flora at phylum level,and the proportion of Blastomonas,Lactococcus,Chryseobacterium,Bacillus and Aquabacterium were increased in the group A and B's colonic flora at genus level(P<0.05).On PND7,no statistically significant differences were found in the Alpha diversity or Beta diversity of colonic flora between the group A and B,the distribution of colonic flora presented no statistically significant differences between the group A and B at phylum level(P>0.05),while the the proportion of Lactobacillus in group B's colonic flora was much higher than that in the group A at the genus level(P<0.05).On PND42,compared with the group A,the shannon index of colonic flora was increased while the simpson index of colonic flora was decreased in the group B,the Beta diversity of colonic flora was significantly different between the group A and the group B,the proportion of Bacteroidetes and Verrucomicrobia was increased while the proportion of Firmicutes and Planctomycetesponycetes was decreased in group B's colonic flora,the proportion of Prevotella?akkermansia and Ruminococcus was increased while the proportion of Staphylococcus and Blastomonas was decreased in group B's colonic flora(P<0.05).On PND 42,The Alpha diversity,Beta diversity and distribution of colonic flora at phylum and genus levels showed no significant differences between the group B and C(P>0.05).Conclusion:The changes in the intestinal flora of rats caused by antibiotic exposure in early life can last until the puberty.The prophylactic application of LR DSM 17938can correct the changes in intestinal flora of pubertal rats caused by antibiotic exposure in early life and help to rebuild healthy intestinal microbial community more quickly. |
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