Enterococcus parabiotic regulate inflammatory responseinduced by Poly (I:C) in the lungs of mice

Background and Aim : The probiotic paradox states both live and dead cells in probiotic productscan generate beneficial biological responses and the term parabiotics was selected to indicate theinactivated dead probiotics cells. Enterocooci are lactic acid bacteria (LAB) and because of theirtolerance to salts and acids, and the production of antimicrobial bacteriocins were traditionallyaccept as probiotic and involved in the preparation of fermented foods. However concerns overthe safety of Enterococcus spp. as a probiotic have been increasingly raised todays. In the currentstudy we used the Enterococcus sp. parabiotic to manage the lung inflammation in mice followingthe administration of viral mimic Poly inosinic:polycytidylic acid (poly I:C).Methods : Enterococcus cells (that was previously obtained from the traditional pickles) wereinactivated by heat pre-treatment at ۸۰ ºC for ۳۰ min.Male BALB/c mice, ۸-۱۲ weeks-old, wereintranasally administered ۲۰ μL of Enterococcus parabiotic (۱۰⁸ CFU/mL) for ۵ consecutive daysunder inhalation anesthesia with isoflurane. Mice received three doses of ۲۰ μl poly (I:C) (۱mg/ml) on days ۶-۸ and were euthanized on day ۹ i.e. ۲۴ h after the last intranasal treatment.Control animals received phosphate buffered saline(PBS) instead of parabiotic. The immunemodulatoryactivity of Enterococcus parabiotic was determined based on the measure of cytokinelevels in the BALF (bronchoalveolar tissue lavage fluid), lung histology, and the lung wet-to-dry(W/D) weight ratioResults : The quantitative analysis of pro-inflammatory cytokines revealed that TNF-?, IL-۱? andIL-۶ were significantly reduced by ۳.۱, ۴.۲, and ۴.۴ folds in the mice received inactivatedEnterococcus (P<۰.۰۵). The lung tissue samples from the parabiotic treatment group displayedtypical histology of normal lungs with thin alveolar walls and absence of intra-alveolar edema.Compared with the control group (۶.۷?±?۰.۱۵), the wet/dry weight ratios of lung tissues in theparabiotic group (۵.۷?±?۰.۱۳) were significantly decreased(P<۰.۰۵).Conclusion : Our findings indicate that Enterococcus parabiotic modulates the inflammatoryresponse in bronchial epithelial cells and it can be a useful tool to manage the acute respiratorydistress syndrome (ARDS).

کلیدواژه ها:

Enterococcus ، Parabiotic ، Acute respiratory distress syndrome ، Inflammation