| Objective:Applying mouse model, this essay is to observe the influence of dexamethasone-contaminated water on the mouse growth and intestinal microflora composition, estimate the possible harm of dexamethasonecontaminated water on creature, provide experimental basis for prevention and treatment of examethasone-contaminated water. Also, it is to explore and the preventive effects of degradating bacteria on the influence of dexamethasone-contaminated water on the mouse growth and intestinal microflora composition, provide experimental basis and effective measures for the bioremediation technology control the harm of dexamethasonecontaminated water on creature.Methods:(1)Referring to the reports of examethasone-contaminated water at home and abroad, Totally 20 Balb/c mice were randomly divided into control group, low-, medium- and high-dose experimental groups.Low-dose group was orally administered with water containing 7ng/L dexamethasone sodium phosphate, the dosage medium-dose group was45ng/L, high-dose group was 450ng/L, and control group was orally administered with orally administered with water without containing dexamethasone sodium phosphate. Mouse body weights were recorded, the mouse appearance and behavior were observed after treatment. After mice sacrificed, organ weight analysis was performed. Intestinal microflora composition was analyzed with denaturing gradient gel electrophoresis(DGGE) and 16 S rDNA V6 sequencing.(2)Totally 32 Balb/c mice were randomly divided into contaminative group, prevention group, degradating bacteria group and control group,there were 8 mice in each group. First, each group was orally administered with 5% sodium bicarbonate solution 0.2mL to neutralize peptic acid. Then the contaminative group and control group were orally administered with aseptic PBS solution 0.2mL, the prevention group and degradating bacteria group were orally administered with 0.2mL bacterium solution, containing1x108CFU/mL bacteria degradating dexamethasone. From day 9 to day 42,the contaminative group and prevention group wre orally administered with0.2mL solution, containing 0.005g/L of dexamethasone sodium phosphate;degradating bacteria group and control group were orally administered with0.2mL sterile saline. The mouse weight of each group was analysed at three measure time, the day before treatment, day 8 and day 43 of treatment. Onthe 43 th day of treatment, the mice were sacrificed, the abdominal aortic blood was taken to detect the serum TARP; the right femur bone of mouse was taken to analyze bone histomophormetry; the liver, spleen and double kidney were taken to compute viscera coefficient; the ileocecal region tissue was collected sterilely, 3 randomly were selected to extract bacterial genome DNA, and then amplificated 16 S rRNA V4 variable area, the Illumina high-throughput sequencing technologies was used to detect ileocecal diversity of microbial flora.Results:(1) Messy fur and hostile behavior were observed in mice in the experimental groups. Compared with the conrrol group, the mouse body weights in the high-, medium-, low-dose group were significantly declined.Moreover, the liver and spleen coefficients were significantly elevated in the experimental groups. DGGE profiling indicated stable intestinal microflora composition in mice. Principal component analysis(PCA)showed significant differences in the dominant microflora between the control and experimental groups. Microflora diversity analysis showed that,compared with the control group, the intestinal microflora amount and species were significantly increased in the experimental groups, especially for the medium- and high-dose groups. 16 S rDNA V6 sequencing revealed totally 17 species of intestinal microflora, 15 of which were detected in all the groups. For the other 2 species, Lactobacillus bacteria existed only inthe control group, while Shigella bacteria were observed only in the medium- and high-dose groups.(2)Messy fur and hostile behavior were also observed in mice in the contaminative group. Compared with the conrrol group, the mouse body weight in the contaminative group was significantly declined, the liver coefficient was significantly elevated, and the spleen coefficient was obviously elevated; bone histomophormetry and the content of serum TRAP showed significant changes of osteoporosis; the intestinal microflora amount and species were significantly decreased. The mouse body weight in the prevention group was obviously declined, the spleen coefficient was obviously elevated; bone histomophormetry and the content of serum TRAP showed obvious changes of osteoporosis;the intestinal microflora amount and species were decreased, but less obvious than contaminative group.The above-mentioned indexes did not show obvious differences in degradating bacteria group. Helicobacter, Uncultured Lachnospira,Mucispirillum and Blautia were fund in mouse ileocecal region of each group, and the relative abundance of them is above 75.1%.The relative abundance of Helicobacter, Mucispirillum in contaminative group was higher than control group; the relative abundance of them in prevention group were also higher than control group, but lower than contaminative group; the relative abundance of them in degradating bacteria group were close to control group. Each group except contaminative groupcontained lactobacillus bacteria, Shigella bacteria were mainly found in contaminative group. Although, Shigella bacteria were also found in prevention group, its amount was significantly less than contaminative group. The amount of Pseudomonas bacteria increased significantly in the prevention group and degradating bacteria group.Conclusion:(1)Dexamethasone-contaminated water reduces the mouse growth,alters the intestinal microflora composition, inhibits the probiotic colonization, and facilitates the invasion of pathogenic bacteria.(2)Orally administered with 0.005g/L dexamethasone sodium phosphate invokes changes of mouse growth and intestinal microflora composition, inhibits bone metabolism and leads to osteoporosis.(3)To a certain extent, orally administered with degradation bacteria can weaken the influence of dexamethasone sodium phosphate with mouse growth, intestinal microflora composition and osteoporosis. |
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