Investigating the effects of Modified Sijunzi Decoction on the diversity of intestinal microflora of severe scald rabbits based on 16S ribosomal RNA high-throughput sequencing / 中华烧伤杂志

ABSTRACT

Objective: To investigate the effects of Modified Sijunzi Decoction on the diversity of intestinal microflora of in severe scald rabbits based on 16S ribosomal RNA (16S rRNA) high-throughput sequencing. Methods: The experimental research method was adopted. Ninety Japanese big-ear rabbits regardless gender, aged 6 to 8 months, were randomly divided into normal control group, scald alone group, scald+low-dose group, scald+medium-dose group, and scald+high-dose group, with 18 rabbits in each group. The rabbits in normal control group were free to eat and drink, and the rabbits in scald alone group, scald+low-dose group, scald+medium-dose group, and scald+high-dose group were intragastrically administered normal saline, 0.2 g/mL Modified Sijunzi Decoction, 1.0 g/mL Modified Sijunzi Decoction, and 5.0 g/mL Modified Sijunzi Decoction, respectively for 7 days after sustaining full-thickness scalding of 30% total body surface area. On the 1st, 3rd, and 7th day after grouping, the levels of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-10 in ileal mucosa tissue of rabbits in each group were determined by enzyme-linked immunosorbent assay, and the number of samples in each group at each time point was 6. According to the above experimental results, another 9 rabbits were selected and divided into normal control group, scald alone group and scald+medium-dose group, with 3 rabbits in each group. The grouping and treatment methods of rabbits in each group were the same as before. On the 7th day after grouping, the V3, V4 region of 16S rRNA of ileum mucosa of rabbits in three groups were sequenced by high-throughput sequencing technology. The number of quality bacteria was counted by QIME software. The classifications of phylum, class, order, family and genus of microflora were analyzed by RDP Classifier software. The α diversity (Ace, Chao1, Simpson, and Shannon indexes) and β diversity were analyzed by Illumina MiSeq sequencing technology, and the number of experiment samples in each group was 3. Data were statistically analyzed with analysis for variance of factorial design, SNK test, and Bonferroni correction. Results: Compared with that in normal control group, the levels of TNF-α of ileal mucosa tissue of rabbits in scald alone group, scald+low-dose group, and scald+high-dose group on the 1st, 3rd, and 7th day after grouping and scald+medium-dose group on the 1st and 3rd day after grouping were all significantly increased (P<0.01), the levels of IL-1β in ileal mucosa tissue of rabbits in scald alone group, scald+low-dose group, scald+medium-dose group and scald+high-dose group on the 1st, 3rd, and 7th day after grouping were all significantly increased (P<0.05 or P<0.01), and the levels of IL-10 in ileal mucosa tissue of rabbits in scald alone group, scald+low-dose group, scald+medium-dose group, and scald+high-dose group on the 1st, 3rd, and 7th day after grouping were all significantly decreased (P<0.01). Compared with that in scald alone group, the levels of TNF-α in ileal mucosa tissue of rabbits in scald+low-dose group, scald+medium-dose group, and scald+high-dose group on the 3rd and 7th day after grouping, and scald+medium-dose group on the 1st day after grouping were all significantly decreased (P<0.01), and the levels of IL-1β in ileal mucosa tissue of rabbits in scald+low-dose group, scald+medium-dose group, and scald+high-dose group on the 3rd and 7th day after grouping and scald+medium-dose group on the 1st day after grouping were all significantly decreased (P<0.01), and the levels of IL-10 in ileal mucosa tissue of rabbits in scald+low-dose group on the 7th day after grouping and scald+medium-dose group on the 1st, 3rd, and 7th day after grouping and scald+high-dose group on the 3rd and 7th day after grouping were all significantly increased (P<0.05 or P<0.01). Compared with that in scald+low-dose group, the levels of TNF-α in ileal mucosa tissue of rabbits in medium-dose scald alone group on the 1st, 3rd, and 7th day after grouping and in high-dose scald alone group on the 3rd and 7th day after grouping were significantly decreased (P<0.01), and the levels of IL-1β in ileal mucosa tissue of rabbits in medium-dose scald alone group on the 1st, 3rd, and 7th day after grouping and in high-dose scald alone group on the 3rd and 7th day after grouping were all significantly decreased (P<0.05 or P<0.01), and the levels of IL-10 in ileal mucosa tissue of rabbits in scald+medium-dose group on the 1st, 3rd, and 7th day after grouping and in scald+high-dose group on the 7th day after grouping were all significantly increased (P<0.05 or P<0.01). Compared with that in scald medium-dose group, the levels of TNF-α in ileal mucosa tissue of rabbits in scald+high-dose group on the 1st, 3rd, and 7th day after grouping were all significantly increased (P<0.01), and the levels of IL-10 in ileal mucosa tissue of rabbits in scald+high-dose group on the 1st, 3rd, and 7th day after grouping were all significantly decreased (P<0.01), and the levels of IL-1β in ileal mucosa tissue of rabbits in scald+high-dose group on the 7th day after grouping was significantly decreased (P<0.01). Compared with that on the 1st day after grouping, the levels of TNF-α in ileal mucosa tissue of rabbits in scald alone group on the 3rd and 7th day after grouping and in normal control group on the 3rd day after grouping were all significantly increased (P<0.05 or P<0.01), and the levels of IL-1β in ileal mucosa tissue of rabbits in scald alone group both on the 3rd and 7th day after grouping were significantly increased (P<0.01), and the levels of IL-10 in ileal mucosa tissue of rabbits in both scald+low-dose group and scald+high-dose group on the 7th day after grouping and scald+medium-dose group both on the 3rd and 7th day after grouping were significantly increased (P<0.05 or P<0.01), and the levels of TNF-α in ileal mucosa tissue of rabbits in scald+high-dose group on the 3rd and 7th day after grouping and in scald+medium-dose group on the 7th day after grouping were all significantly decreased (P<0.05 or P<0.01), and the level of IL-1β in ileal mucosa tissue of rabbits in scald+medium-dose group on the 7th day after grouping was significantly decreased (P<0.01), and the level of IL-10 in ileal mucosa tissue of rabbits in scald alone group on the 7th day after grouping was significantly decreased (P<0.01). Compared with that on the 3rd day after grouping, the levels of TNF-α and IL-1β in ileal mucosa tissue of rabbits in scald alone group and the levels of IL-10 in ileal mucosa tissue of rabbits in normal control group, scald+low-dose group, scald+medium-dose group, and scald+high-dose group on the 7th day after grouping were all significantly increased (P<0.05 or P<0.01); and the levels of TNF-α in ileal mucosa tissue of rabbits in scald+low-dose group, scald+medium-dose group, and scald+high-dose group on the 7th day after grouping were all significantly decreased (P<0.05), and the levels of IL-1β in ileal mucosa tissue of rabbits both in scald+medium-dose group and scald+high-dose group on the 7th day after grouping were significantly decreased (P<0.05 or P<0.01), and the levels of IL-10 in ileal mucosa tissue of rabbits in scald alone group on the 7th day after grouping was significantly decreased (P<0.01). On the 7th day after grouping, the high-quality sequences obtained from the microflora in ileum mucosa of rabbits in normal control group, scald alone group, and scald+medium-dose group were 96 023, 107 365, and 95 921, respectively. At the classification level of phylum, class, order, family, and genus of the microflora in ileum mucosa of rabbits in three groups were all Bacteroidetes and Firmicutes, Clostridium and Bacteroidetes, Clostridium and Bacteroidetes, Rumenobacteriaceae and Clostridium and Bacteroideaceae, Clostridium and Bacteroidetes and rumen bacteria mainly, while the percentage of microflora in each group was different. There were no significant differences in Ace, Chao1, Simpson, Shannon indices (P>0.05), and no obvious difference in β diversity of microflora in ileal mucosa tissue of rabbits among three groups. Conclusions: After severe scalding, the inflammatory response of rabbit ileal mucosa tissue is obvious and increased in a time-dependent manner. Modified Sijunzi Decoction can reduce inflammation with optimal therapeutic concentration of 1.0 g/mL. The technology of high-throughput sequencing can reflect the structural composition of the intestinal microflora accurately. The ileal microflora of the severe scald rabbit can be regulated by the administration of Modified Sijunzi Decoction.