A Mixture of Five Bacterial Strains Attenuates Skin Inflammation in Mice

Background: There is a growing interest in the effects of probiotics for the prevention and treatment of skin diseases due to their immunomodulatory and antiinflammatory properties. Objective: To assess a mixture of five bacterial strains in the prevention of chronic skin inflammation in mice. Methods: Hairless SKH-1 mice received daily oral treatment with the probiotic mixture at the dose of 1x109 Colony-Forming Unit (CFU)/day (or vehicle) for three weeks. Chronic skin inflammation was induced by repeated applications of 12-O-tetradecanoylphorbol-13- acetate (TPA; control mice received acetone). Macroscopic and microscopic evaluations of skin lesions were performed and serum levels of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, IL-17, IL-22, IL-10 and IL-4 measured at the end of the study. Results: Treatment with the probiotic mixture significantly limited the induced chronic skin inflammation at both the macroscopic and microscopic levels. This limitation was consistent with downregulated levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, IL- 17 and IL-22) and up-regulated levels of the anti-inflammatory cytokines, IL-10 and IL-4. Conclusion: The results suggest that the probiotic mixture tested could help in preserving skin integrity and homeostasis and that its use could be beneficial in dermatological conditions such as atopic dermatitis and psoriasis.