Exosomes Derived from Adipose Mesenchymal Stem Cells Promote Diabetic Chronic Wound Healing through SIRT3/SOD2.

Chronic wounds resulting from diabetes are a major health concern in both industrialized and developing countries, representing one of the leading causes of disability and death. This study aimed to investigate the effect of adipose mesenchymal stem cell-derived exosomes (ADSC-exos) on diabetic wounds and the mechanism underlying this effect. The results showed that ADSC-exos could improve oxidative stress and secretion of inflammatory cytokines in diabetic wounds, thereby increasing periwound vascularization and accelerating wound healing. At the cellular level, ADSC-exos reduced reactive oxygen species (ROS) generation in human umbilical vein endothelial cells (HUVECs) and improved mitochondrial function in a high-glucose environment. Moreover, the Western blot analysis showed that the high-glucose environment decreased Sirtuin 3 (SIRT3) expression, while exosome treatment increased SIRT3 expression. The activity of superoxide dismutase 2 (SOD2) was enhanced, and the level of inflammatory cytokines was decreased. Further, SIRT3 interference experiments indicated that the effects of ADSC-exos on oxidative stress and angiogenesis were partly dependent on SIRT3. After SIRT3 was inhibited, ROS production increased, while mitochondrial membrane potential and SOD2 activity decreased. These findings confirmed that ADSC-exos could improve the level of high-glucose-induced oxidative stress, promote angiogenesis, and reduce mitochondrial functional impairment and the inflammatory response by regulating SIRT3/SOD2, thus promoting diabetic wound healing.