Wnt7a Promotes Wound Healing By Regμlation Of Angiogenesis And Inflammation

Background:Diabetic skin heals wounds poorly.Healing is a complicated and dynamic process,including three overlapping phases:inflammation,reproduction and remodeling phases,together with many cells,chemokines and signaling pathways.It is of great importance to fully understand the molecular mechanism of diabetic wound healing in order to prevent and cure this delayed process,which is difficult and tough as the malfunction of many kinds of cells including the lack of angiogenesis and increased local inflammation endothelial cells.Though obesity is the common risk factor of diabetes mellitus,few studies have investigated its effects on wound healing.Objectives:This study aimed to evaluate the morphology and possible mechanism of Human umbilical vein endothelial cells(HUVECs)in response to different levels of glucose and palmitic acid,and picked out the significantly changed protein in the wnt signaling pathway-Wnt7a,and finally evalute the role of Wnt7a in wound healing from both cell and animal experiments based on the endothelial cells.Methods:The functional changes of HUVECs and mRNA expression of Wnt signaling were determined by analyzing cell viability,migration,tube formation and rt-PCR in gradients of D-glucose(Glc)and palmitic acid(PA).To establish the diabetic rat model,SD rats were intraperitoneally injected with STZ once(65 mg/kg)and fed with or without a high-fat diet(40%calories from fat;Puluteng,Shanghai,China).After blood sugar keeps steadily over 16.6 mM for 3 weeks,two full-thickness wounds of 13.5 mm in diameter were made on the dorsal surface of 10%chloral hydrate anaesthetized rats.The distance between both wounds was approximately 15 mm.Rats were injected phosphate buffered saline,PBS diluted recombinant Wnt7a(100 ng per wound)that localized around lesion edge every other day after wounding and the same amount PBS injection as control.Angiogenesis and inflammatory statement were mainly analyzed by immunohistochemistry,ELISA,cytometry and Western blotting.Results:The expression of Wnt7a significantly decreased in high Glc/PA cμltured cells or DM and HF wounded rats.Impaired wound healing was also observed in DM and HF groups.The healing rate significantly accelerated after localized injection with Wnt7a at d10.Moreover,the expression of CD31,eNOS phosphorylation and NO were increased;the reduction of local neutrophils influx,ICAM-1 and IL-6/8 expression levels were obvious especially in diabetic with obesity rats at d10 after Wnt7a treatment.Conclusion:This study indicates the potential role of Wnt7a,which is beneficial for regeneration of damaged vessels,moderation of inflammatory statement in diabetic wound healing with or without obesity,thus demonstrating its possible utility as a topical administration to promote healing rate.