Evaluation of antioxidant and antibacterial effects of lactobacilli metabolites- preconditioned bone marrow mesenchymal stem cells in skin lesions amelioration

Mesenchymal stem cells (MSCs) therapeutically intensify wound-healing. Meanwhile, probiotics are capable to inhibit pathogenic bacteria by secreting antimicrobial and antioxidant agents. They ameliorate more the wounds, by MSCs' synergistic effect.This way, MSCs exposed to probiotics metabolites (the extracts of Lactobacillus plantarum and Lactobacillus casei), become more viable, and the optimum doses of probiotics metabolites were determined by Trypan blue and MTT assays. Then, preconditioned MSCs (pre-MSCs) faced again the oxidative stress (100 µM H2O2), and their survival rate was assessed by MTT assay. Conditioned medium (CM) prepared from pre-MSCs and the expression rate of antioxidant proteins evaluated by Real-time PCR. The antimicrobial activity of the samples was evaluated using the MIC method. Then mice wound models were treated with the mixture of a basal ointment and each CM of pre-MSCs. The proliferation and viability of MSCs improved by the probiotic's metabolites preconditioning (P ≤ 0.05). pre-MSCs exhibited significant up-regulated in antioxidant genes expression (P ≤ 0.001). Also, probiotics metabolites presented a significant free radical scavenging effect (P ≤ 0.001). CMs of pre-MSCs showed considerably increased antibacterial activity (P ≤ 0.05). Experimental groups compared with the controls revealed that wound contraction was more rapid in groups that received CMs of LP-MSCs, LC-MSCs, MSCs, and then finally mixed probiotics metabolites, respectively.These results provide a novel insight into the probiotics extract effect on the improvement of MSCs' potential for wound healing procedures.