Probiotic-Derived Exopolysaccharides Enhance Mesenchymal Stem Cell-Mediated Fibroblast Repair under Hyperglycemic Conditions

Abstract Diabetic wounds are closely associated with persistent oxidative stress, decreased fibroblast activity, and delayed tissue regeneration under hyperglycemic conditions. These pathological features particularly complicate wound healing and often lead to chronic non-healing wounds. Recently, mesenchymal stem cells (MSCs) and probiotic-derived biomolecules have attracted attention as potential agents to improve tissue repair. In this study, we examined whether the combination of adipose-derived mesenchymal stem cell-conditioned medium (ADMSC-CM) and bacterial exopolysaccharides (EPSs) could improve fibroblast responses under diabetes-like conditions. EPSs were extracted from Lactobacillus plantarum and Lactobacillus brevis, purified and preliminarily characterized prior to subsequent cell-based experiments. To stimulate a diabetic microenvironment, L929 fibroblasts were exposed to high-glucose conditions prior to treatment with ADMSC-CM, purified EPSs, or their combination. Cell viability, oxidative stress levels, apoptosis, and migration potential were assessed using the MTT assay, DCFH-DA staining, acridine orange/propidium iodide staining, and scratch assay, respectively. Interestingly, the combination of ADMSC-CM with L. brevis-derived EPS showed the strongest effect. This treatment improved fibroblast viability and wound closure under hyperglycemic conditions while significantly reducing intracellular ROS levels and apoptotic cell death. EPS derived from L. plantarum also showed supportive effects, but these regenerative responses were relatively weaker. Both EPS fractions were found to be biocompatible at 1000 μg/mL. Overall, these findings suggest that probiotic-derived EPS can enhance ADMSC-mediated fibroblast repair in a hyperglycemic microenvironment and serve as a supportive bioactive agent in diabetic wound healing.