Innovative Animal Model of DSS-Induced Ulcerative Colitis in Pseudo Germ-Free Mice

The aim of this study was to investigate the use of a standardized animal model subjected to antibiotic treatment, and the effects of this treatment on the course of dextran sodium sulphate (DSS)-induced colitis in mice. By decontamination with selective antibiotics and observation of pathogenesis of ulcerative colitis (UC) induced chemically by exposure of mice to various concentrations of DSS, we obtained an optimum animal PGF model of acute UC manifested by mucin depletion, epithelial degeneration and necrosis, leading to the disappearance of epithelial cells, infiltration of lamina propria and submucosa with neutrophils, cryptitis, and accompanied by decreased viability of intestinal microbiota, loss of body weight, dehydration, moderate rectal bleeding, and a decrease in the selected markers of cellular proliferation and apoptosis. The obtained PGF model did not exhibit changes that could contribute to inflammation by means of alteration of the metabolic status and the induced dysbiosis did not serve as a bearer of pathogenic microorganisms participating in development of ulcerative colitis. The inflammatory process was induced particularly by exposure to DSS and its toxic action on compactness and integrity of mucosal barrier in the large intestine. This offers new possibilities of the use of this animal model in studies with or without participation of pathogenic microbiota in IBD pathogenesis

Addressing safety concerns of long-term probiotic use: In vivo evidence from a rat model

The global market for probiotic supplements is continually expanding. However, the certainty of their safety is still a matter of concern. Since multi-strain probiotics are gaining increasing interest in clinical practice, the aim of the presented study was to evaluate the long-term effects of probiotic mixture on healthy Wistar rats with the focus on colon histology, haematology, serum biochemistry, inflammatory cytokine production and faecal microbiota composition. The long-term supplementation resulted in systemic pro-inflammatory response accompanied by increased abundance of bacterial families associated with the promotion of gastrointestinal inflammation. The important indicators of cardiovascular risk were significantly elevated after long-term probiotic treatment. Even though no histopathological lesions were detected in the colon, enlarged lymphoid aggregates and follicles were observed in probiotic-fed rats. Based on our study, commercially available probiotics for human use which are recommended as prophylaxis should be monitored for possible side effect after long-term usage. Our study thus contributes to the increasingly debated proposal of the scientific community which suggests the need to shift the future of probiotic prescription from the current ‘one-size-fits-all’ scheme into a person/condition-tailored approach with defined time of administration

Analysis of biofilm formation by intestinal lactobacilli

In this study, biofilm forming potential of intestinal Lactobacillus reuteri strains under different culture conditions was characterized by microtiter plate biofilm assays. Moreover, the spatial organization of exogenously applied L. reuteri L2/6 (a pig isolate) at the specific locations in gastrointestinal tract of monoassociated mice was investigated by FISH. We did not detect biofilm formation by tested strains in nutrient-rich MRS medium. On the contrary, a highly positive biofilm formation was observed in medium with lower accessibility to the carbon sources and lack of salts. The results obtained confirmed the significant role of Tween 80 and the quantity and nature of the sugars in the growth medium on biofilm formation. The omission of Tween 80 in MRS medium favored the formation of biofilm. Abundant biofilm formation was detected in the presence of lactose, galactose and glucose. However, gradual increase in sugars concentration triggered significant decrease in biofilm formation. In addition, conditions related to the gastrointestinal environment such as low pH, the presence of bile and mucins highly modulated biofilm production. This effect seems to be dependent on the specificity and properties of the medium used for cultivation. From the evidence provided by this study we conclude that the biofilm formation capacity of L. reuteri is strongly dependent on the environmental factors and culture medium used.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

5-Fluorouracil Treatment of CT26 Colon Cancer Is Compromised by Combined Therapy with IMMODIN

Due to the physiological complexity of the tumour, a single drug therapeutic strategy may not be sufficient for effective treatment. Emerging evidence suggests that combination strategies may be important to achieve more efficient tumour responses. Different immunomodulators are frequently tested to reverse the situation for the purpose of improving immune response and minimizing chemotherapy side effects. Immodin (IM) represents an attractive alternative to complement chemotherapy, which can be used to enhance the immune system after disturbances resulting from the side effects of chemotherapy. In the presented study, a model of CT26 tumor-bearing mice was used to investigate the effect of single IM or its combination with 5-fluorouracil (5-FU) on colon cancer cells. Our results highlight that the beneficial role of IM claimed in previous studies cannot be generalised to all chemotherapeutic drugs, as 5-FU toxicity was not increased. On the contrary, the chemotherapeutic anti-cancer efficacy of 5-FU was greatly compromised when combined with IM. Indeed, the combined treatment was significantly less effective regarding the tumour growth and animal survival, most probably due to the increased number of tumour-associated macrophages, and increased 5-FU cytotoxic effect related to kidneys and the liver

Single Donor FMT Reverses Microbial/Immune Dysbiosis and Induces Clinical Remission in a Rat Model of Acute Colitis

Deviation in the gut microbial composition is involved in various pathologies, including inflammatory bowel disease (IBD). Faecal microbiota transplant (FMT) can act as a promising approach to treat IBD by which changes in microbiome can be reversed and homeostasis restored. Therefore, the aim of this study was to investigate the effect of FMT on the remission of acute inflammatory response using dextran sulfate sodium (DSS)-induced rat colitis model. Faecal microbial communities were analysed using the 16S rRNA approach, and clinical manifestations together with histological/haematological/biochemical/immunological analyses were assessed. Our study demonstrated significant shifts in the dominant species of microbiota under inflammatory conditions induced by DSS and evident restoration effect of FMT treatment on microbial composition. These faecal microbial alterations in FMT-treated rats led to a relative restoration of colon length, and a significant decrease in both epithelium damage and disease severity, which was reflected in lower serum pro-inflammatory cytokine levels. Haematological/biochemical parameters in DSS-treated animals showed signs of anaemia with a significant reduction in red blood cell count together with increasing levels of total bilirubin, creatinine and phosphorus suggesting potential protective effect of FMT. These results support FMT as a valuable therapeutic strategy to control inflammation during acute colitis

Dextran Sulphate Sodium Acute Colitis Rat Model: A Suitable Tool for Advancing Our Understanding of Immune and Microbial Mechanisms in the Pathogenesis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of disorders causing inflammation in the digestive tract. Recent data suggest that dysbiosis may play a pivotal role in the IBD pathogenesis. As microbiome-based therapeutics that modulate the gut ecology have been proposed as a novel strategy for preventing IBD, the aim of presenting study was to evaluate the dextran sulphate sodium (DSS) rat model mainly in terms of microbial shifts to confirm its suitability for dysbiosis study in IBD. Acute colitis was induced using 5% DSS solution for seven days and rats were euthanized five days after DSS removal. The faecal/caecal microbiota was analyzed by next generation sequencing. Disease activity index (DAI) score was evaluated daily. Blood and colon tissue immunophenotyping was assessed by flow cytometry and histological, haematological, and biochemical parameters were also evaluated. The colitis induction was reflected in a significantly higher DAI score and changes in all parameters measured. This study demonstrated significant shifts in the colitis-related microbial species after colitis induction. The characteristic inflammation-associated microbiota could be detected even after a five day-recovery period. Moreover, the DSS-model might contribute to an understanding of the effect of different treatments on extraintestinal organ impairments. The observation that certain bacterial species in the gut microbiota are associated with colitis raises the question of whether these organisms are contributors to, or a consequence of the disease. Despite some limitations, we confirmed the suitability of DSS-induced colitis model to monitor microbial changes during acute colitis, in order to test attractive new microbiome-based therapies

Effect of thymol and Enterocin M administration on biochemical, antioxidant and immunological parameters, small intestinal morphology and microbiota in rabbits.

To find natural feed additives with a beneficial effect on rabbit health, thymol alone and in combination with Enterocin M were administered in drinking water for 42 days (35 -77 days of age). A total of 48 rabbits based on their weight were randomly divided into four experimental groups: C – control (basal diet), T – thymol (250 mg/L), E – Enterocin M (Ent M) (50 μL/animal/day), T + E (thymol with Ent M). Ent M (p < .05) and thymol (p < .01) separately decreased malondialdehyde in the liver. Thymol separately and in combination significantly increased phagocytic activity in the blood (p = .0051) and lactic acid in the caecum (p = .0142) and decreased coagulase-positive staphylococci in the caecum (p = .0329). Ent M separately and in combination increased immunoglobulin A content in the jejunal wall (p = .002) and decreased coliform bacteria in faeces (p = .0002). Thymol and Ent M application separately or in combination improved the antioxidant and immune response of rabbits and demonstrated an antibacterial effect

Effect of thymol and Enterocin M administration on biochemical, antioxidant and immunological parameters, small intestinal morphology and microbiota in rabbits

To find natural feed additives with a beneficial effect on rabbit health, thymol alone and in combination with Enterocin M were administered in drinking water for 42 days (35 -77 days of age). A total of 48 rabbits based on their weight were randomly divided into four experimental groups: C - control (basal diet), T - thymol (250 mg/L), E - Enterocin M (Ent M) (50 lL/animal/day), TthornE (thymol with Ent M). Ent M (p <.05) and thymol (p <.01) separately decreased malondialdehyde in the liver. Thymol separately and in combination significantly increased phagocytic activity in the blood (p = .0051) and lactic acid in the caecum (p =0142) and decreased coagulase-positive staphylococci in the caecum (p =.0329). Ent M separately and in combination increased immunoglobulin A content in the jejunal wall (p =.002) and decreased coliform bacteria in faeces (p =.0002). Thymol and Ent M application separately or in combination improved the antioxidant and immune response of rabbits and demonstrated an antibacterial effect