Promotive Effect Of Transdermal Administration Of Chiglitazar On Wound Healing In Diabetic Mice

Objective:The peroxisome proliferator-activated receptor（Peroxisome proliferator-activated receptors,PPARs）is widely distributed in the body and all of three isoforms（PPARα,PPARβ,and PPARγ）of PPARs have been shown to promote wound healing when activated.Chiglitazar is the world’s first marketed PPARs pan-agonist that treats type 2 diabetes while mitigating the adverse effects caused by over-activation of single receptor through balanced activation of the three PPARs.This mechanism may promote the healing of chronic wounds while treating diabetes.Through in vitro and in vivo research,this study intends to investigate the effect of Chiglitazar on diabetic wound healing through in vitro and in vivo experiments,may offer a theoretical and experimental foundation for Chiglitazar’s potential therapeutic expansion.Methods:Combined with the preparation process of Chiglitazar administration solution and the feedback of cell count（CCK-8）method,adjusted the ratio of the solution.the cell state of diabetic patients was simulated by special high glucose medium or inflammation-inducing factors.The effect of Chiglitazar on macrophage RAW 264.7,skin cell HaCaT and HSF’s cell activities in high glucose environment was demonstrated by cell counting（CCK-8）;the effect of Chiglitazar on immune cell function was demonstrated by nitric oxide and reactive oxygen species level assays.The effect of Chiglitazar on skin cell migration in the high glucose environment was verified by cell scratch assay.The levels of relevant cytokines were measured by ELISA.According to the results of in vitro experiments and relevant literature,the appropriate concentration of in vivo administration was deduced,and the hydrogel was prepared.The properties and release degree of hydrogel were investigated,and the appropriate hydrogel was selected as the drug delivery carrier.We created a diabetic mouse wound model and applied hydrogel to it.The effect of Chiglitazar hydrogel on diabetic wounds was initially proved through the change of wound area and spleen index.The mechanism of Chiglitazar hydrogel promoting wound healing in diabetic mice was speculated by the detection of related cytokines in mouse serum and the results of CD31immunohistochemical staining.Results:In the in vitro test,based on the experimental results,the ratio of co-solvent was adjusted to 9:1:0.05 for distilled water:DMSO:Tween 80;a diabetic cell model was established and the dose range of Chiglitazar was determined:0.4～6.4μg.m L^-1.The results of in vitro experiments showed that Chiglitazar improved the inhibitory effect of high glucose on macrophage activity,increased the anti-inflammatory and antioxidant capacity of macrophages,promoted the cellular activity of HaCaT and HSF,and also improved the inhibitory effect of high glucose on the migration of HaCaT at the dose of6.4μg.m L^-1.This effect might be mediated by inhibiting the pro-inflammatory factor TNF-αand promoting the expression of anti-inflammatory factors.In terms of formulation,the initial deduced concentration of Chiglitazar administration hydrogel was 5 mg.m L^-1.Two kinds of hydrogels,carbomer and polyethylene glycol,were successfully prepared.Based on the properties of hydrogels,pre-experimental results and drug release degree,polyethylene glycol hydrogel was finally used as the administration hydrogel,and the in vivo experimental method was improved;in the in vivo experiments,a wound model of diabetic mice was successfully established.To monitor the state of wound healing,polyethylene glycol hydrogel was given.The experimental results showed that Chiglitazar polyethylene glycol hydrogel significantly（P<0.05）improved the wound healing progress in diabetic mice,the spleen index of diabetic mice increased significantly（P<0.01）.After administration,the pro-inflammatory factors such as IL-1βand TNF-αin the serum of diabetic mice decreased significantly（P<0.01）,and the angiogenesis of wound tissue increased.Conclusion:As a peroxisome proliferator-activated receptor pan-agonist,Chiglitazar promoted wound healing in diabetic mice by inhibiting the overproduction of pro-inflammatory factors such as IL-1βand TNF-α,improving the anti-inflammatory and antioxidant capacity of macrophages,promoting the proliferation and migration of skin cells;and promoting angiogenesis.