Secretome of Mesenchymal Stem Cells Grown in Hypoxia Accelerates Wound Healing and Vessel Formation In Vitro

Abstract

Hypoxia is one of the factors that trigger the release of inflammatory and vasculogenic cytokines during tissue regeneration. Mesenchymal stem cells (MSC) with and without endothelial cells (EC) were cultured in vitro in normoxic and hypoxic environments. The mRNA expression of inflammatory and vasculogenic cytokines were evaluated at 1, 12, 24 and 48 hours. After 48 hours of incubation in normoxic and hypoxic conditions, supernatants termed as conditioned medium (CM) from each group were collected and analyzed. The protein level of VEGF-A in the CM was determined by ELISA. The effects of the CM from different groups on EC were evaluated using wound healingand tube formation assays. The mRNA expression of IL-1β, IL-6 and IL-8 was up-regulated in both the normoxic and hypoxic co-culture (MSC/EC) group, compared with the mono-culture normoxic group. The VEGF-A protein level was higher in the hypoxic monoand co-culture group. Wound closure was accelerated by CM from the monoand co-culture hypoxic groups compared with both normoxic groups. Measurements of tube formation were higher in the hypoxic mono-culture group compared with the normoxic group. The conditioned medium obtained from hypoxia preconditioning of the cells accelerated wound healing and vessel formation in vitro.