OBJECTIVE: The use of beneficial bacteria may stimulate wound healing. We performed a randomized, placebo-controlled double-blind cross-over study comprising ten healthy volunteers. The aim was to investigate the impact of topical and systemic applications of probiotic lactobacilli (Lactobacillus reuteri) on the healing of standardized wounds (punch biopsies) in the oral mucosa. The expression of selected matrix metalloproteinases (MMP'S) and interferons (IFN's) was analyzed with multiplex immunoassays in the wound exudate during the first healing week (day 2, 5 and 8).

RESULTS: All participants completed the study and in all cases, the healing after the punch biopsies was uneventful. The concentrations of MMP-1, MMP-2, MMP-3 decreased with time in both the test- and control group. The MMP levels were consistently lower during the probiotic intervention when compared with placebo but the differences were not statistically significant. Likewise, the concentrations if IFN-alpha2, IFN-beta and IFN-gamma decreased with time with no significant differences between the test and placebo interventions. Within the limitations of this pilot study, we were unable to demonstrate an influence of probiotic supplements containing L. reuteri on the concentrations of selected matrix metalloproteinases and interferons from mucosal wounds within 1 week after a standardized punch biopsy. Trial registration ClinicalTrials.gov Identifier NCT03210779. Date of registration: July 7, 2017.