Anti-inflammatory and Ameliorative effects of two newly isolated probiotic strains in DSS-induced mouse model of colitis

Abstract

Background: Protective effects of probiotics in human diseases have been well documented in recent years. In this study, the anti-inflammatory and fibrinolytic properties of two newly isolated probiotic bacteria, Lactiplantibacillus plantarum and Lactococcus lactis either alone or in combination with standard therapy, Mesalazine (MSZ), have been investigated in a murine model for ulcerative colitis. Methods: Characterization of newly isolated probiotic were assessed by performing antibacterial activity, antibiotic resistance, acid and bile tolerance, and hemolytic activity assays. Hematoxylin-Eosin and Masson's trichrome staining were used to evaluate inflammation and collagen deposition in colon tissue sections. Expression of inflammatory- and Fibrotic-associated genes were analyzed using Real-time PCR and ELISA assays. Results: Results showed that administration of probiotics significantly attenuated DSS-induced colon shortening, colon weight loss, and increase in spleen weight in colitis mice. Compared to the colitis mice, disease activity index as assessed by changes in body weight, degree of stool consistency, rectal bleeding, and prolapse was decreased in probiotic-treated group. Mix of probiotics potently improved histopathological score by attenuating crypt loss, mucosal damage, and inflammation score in colitis tissues. Consistently, mRNA and protein levels of pro-inflammatory genes as well as oxidative stress markers were suppressed in the presence of probiotics in colon tissues. Furthermore, probiotic bacteria reduced fibrosis by down-regulating pro-fibrotic genes including Col 1a1 and α-SMA in colon tissue homogenates. Conclusion: These results showed that mix of these newly isolated probiotic bacteria is as potent as the standard treatment and could be utilize as a novel therapy for ulcerative colitis without any observed side effects. Future experiments on these probiotics in other models of UC is needed to completely address the efficacy potency and safety concerns.