Endothelial-overexpressed lipopolysaccharide-associated factor 1 promotes skin wound healing in diabetic mice by affecting the nuclear factor-kappa B signaling pathway

Abstract:

Objective To investigate the effect of endothelial-overexpressed lipopolysaccharide-associated factor 1（EOLA1） on skin wound healing in mice with type 2 diabetes and the related mechanisms.Methods Specific pathogen-free db/db diabetic mice，aged 6 weeks，were used to establish a model of full-thickness skin wound，and the lentivirus with high EOLA1 expression was injected around the wound. The mice were divided into normal control group，empty vector lentivirus group，and EOLA1 lentivirus group. For all mice except those in the normal control group，photos were taken at different time points to observe wound healing； after the samples of the wound and the skin around the wound were collected on day 15 of modeling，HE staining was used to observe wound granulation tissue and inflammatory infiltration，Masson staining was used to observe collagen fiber deposition at the wound，immunofluorescence assay was used to measure ARG1 and iNOS for macrophage typing，and Western blot and real-time PCR were used to measure the protein expression levels of the nuclear factor-kappa B（NF-κB） signaling pathways proteins IκB-α，p-IκB-α，and p65 and the gene expression levels of EOLA1，Toll-like receptor 4（TLR4），tumor necrosis factor-α（TNF-α），and interleukin-1β（IL-1β）.Results Compared with the empty vector lentivirus group，the EOLA1 lentivirus group had a significantly higher speed of skin wound healing and significant increases in the formation of granulation tissue and collagen fibers. The EOLA1 lentivirus group had an increase in the expression of the M2 macrophage marker ARG1 and a reduction in the expression of the M1 macrophage marker iNOS，as well as an increase in the protein expression of IκB-α，a reduction in the protein expression of p-IκB-α，and downregulation of the gene expression levels of TNF-α and IL-1β.Conclusion EOLA1 can inhibit local skin wound inflammation and accelerate wound healing in diabetic mice，possibly by upregulating the expression of IκB-α in macrophages，blocking the activity of p65，and then inhibiting the release of the inflammatory cytokines such as TNF-α and IL-1β，and the phenotype of macrophages changes from M1 type for promoting inflammation to M2 type for promoting healing，suggesting that EOLA1 has the potential to protect diabetic wound from inflammation and promote wound healing.