Preventive and curative effect of a synbiotic-based Lactobacillus paracasei B21060 on dextran sodium sulfate-induced colitis in mice

R Simeoli1, G Mattace Raso1, A Santoro1, P Amero1, R Russo1, M Sanges0,2, A D\'Arienzo0,2, A Calignano1, R Meli1. 1University of Naples Federico II, Department of Experimental Pharmacology Naples 80131, Italy, 2University of Naples Federico II, Department of Clinical and Experimental Medicine Naples 80131, Italy

Ulcerative colitis (UC) is a chronic, relapsing inflammatory bowel disease, whose etiology is currently unknown. At present, strategies to treat UC are primarily targeted to control inflammation during active phases of disease as well as maintain remission during quiescence. In recent years, basic research and clinical studies have led to the recognition of several key factors in the pathogenesis of UC, translating into the development of several novel therapeutic tools, among these, the manipulation of the microbiota by probiotics may be a rational approach for controlling bowel inflammation (1,2). The aim of this study was to determine the effects of a synbiotic formulation composed by Lactobacillus paracasei B21060 plus arabinogalactan and fructo-oligosaccharides (Flortec®) on the murine model of colitis induced by dextran sodium sulfate (DSS). Experimental colitis was induced in male BALB/c mice by 2.5% DSS in drinking water for 5 days. Mice were randomly divided into four groups (n=8 each group) as following: 1. a control animals (CON), 2. DSS treated mice (DSS), 3. DSS mice treated with Flortec® as preventive therapy (PREV) and 4. DSS mice treated with Flortec® as curative therapy (CUR). Daily synbiotic treatment (L. paracasei B21060 2.5x107 bacteria/10g bw; fructo-oligosaccarides 7mg/10g bw, and arabinogalactan 5mg/10g bw by gavage) started seven days before (PREV) or two days after (CUR) DSS challenge. All animals were killed twelve days after challenge induction. Analysis of disease activity, histological assessment, colonic mucosa integrity, inflammatory markers, oxidative stress and neutrophil infiltration was performed for both therapeutic schemes. In DSS mice, we evidenced a significant decrease in animal weight (p<0.05 ), a significant reduction of intestinal length (p<0.05) and colonic length (p<0.05), and an increase in oxidative stress, such as lipid peroxidation, evaluated as malondyaldheide formation (p<0.05), and nitrosylated proteins (p<0.001), evaluated by Western blot analysis. The inflammatory status of the mucosa in DSS animals was also evidenced by the increase in cyclooxygenase (COX)-2 expression and pro-inflammatory cytokine synthesis and neutrophil infiltration (myeloperoxidase determination) (p<0.001). Moreover, a decrease in occludin mRNA levels in the colonic mucosa and serum adiponectin was also observed. Both synbiotic treatments (PREV and CUR) showed a marked protective effect on weight loss, significantly reduced oxidative damage (malonyldyaldheide (µM)/mg protein, PREV 0.93±0.07 P<0.05; CUR 0.83±0.04 p<0.01 vs DSS 1.20±0.08) and improved structural integrity of colon. In addition the beneficial effect of synbiotic was determined by its marked anti-inflammatory effects, decreasing COX-2 and pro-inflammatory cytokine, myeloperoxidase activity (U.MPO/mg protein PREV 4.03±0.98 CUR 3.81±0.55 vs DSS 14.46±2.98; p<0.001) and partially restoring adiponectin levels. Our data showed significant curative effects of this synbiotic formulation in DSS model of colitis and suggests not only a potential therapeutic role for this agent in this pathology, but also the possibility that a supplement of these lactobacilli might prevent the relapse of UC.

References

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