Experimental Study On The Effect Of Aeschynomene Indica L.extract On Cutaneous Wound Healing In Rats

The skin is the biggest organ in human body,it is inevitably get injured because of its direct exposure to the environment.Poor wound healing is still a major and global threat to public health and the economy.An estimated 234 million surgeries are performed globally every year,more than 500,000 serious burn victims are hospitalized annually in the US alone.It has been estimated that 1~2% of the population in developed countries have or had chronic wounds.The wound-care market is expected to be $6.7 billion worldwide,and this amount is anticipated to grow rapidly.Along with the knotty problem of wound healing is the treatment of scars,it has been estimated that the market for anti-scarring drugs is US$12 billion annually.To promote wound healing and ameliorate scars,efforts have been made to better understand the underlying mechanisms and develop effective remedies.However,the success that we have gained so far is still limited,as there are no effective and generally applicable therapies available for skin injuries and fibrosis.Given our present situation,it is imperative to develop new drugs/therapies that effectively facilitate wound healing and improve scars.Aim of the study: To verify the efficacy of Aeschynomene indica L.(AIL)extract in promoting wound healing,and to isolate the active constituent via bio-assay guided fractionation,to reveal the possible mechanisms of enhancing wound healing and ameliorating scars as well.Methods: Purification of the AIL extract were performed by organic solvent extraction and column chromatography.The circular excision wound healing model was used to evaluate in vivo wound-healing activity of AIL extract and fractions.Hematoxylin and eosin staining and sirius red-picric acid staining were employed for histopathological analysis and to quantify the ratio of collagen I/III,respectively.Immunohistochemicalstaining for CD68,CCR7,CD163,TGF-?1,and ?-SMA was performed to determine macrophages phenotypes transition(M1-to-M2)and the process of EMT(Epithelial-Mesenchymal Transition).Results: AIL extract has an obvious promoting effect on wound healing.We successfully isolated the active constituent(Sub-Fr.2)for wound healing from AIL extract via bio-assay guided fractionation.Results of hematoxylin and eosin staining exhibited that wounds of the Sub-Fr.2 group showed inhibited inflammatory cells infiltration,enhanced angiogenesis,fibroblasts proliferation,collagen synthesis,and skin appendages generation,when compared with the vehicle group.Results of sirius red-picric acid staining showed that the content of collagen III was remarkably enhanced in the Sub-Fr.2group,as compared with the vehicle group.Immunohistological staining results of CD68,CCR7,CD163,TGF-?1,and ?-SMA showed that application of the ointment containing Sub-Fr.2 on circular wounds decreased the infiltration of macrophages and enhanced M1-to-M2 macrophages phenotypes transition,as well as inhibited the expression of TGF-?1 and ?-SMA.Conclusion:AIL extract and its active constituent(Sub-Fr.2)effectively promoted wound healing and reduced scar formation.This efficacy was exerted by accelerating macrophages phenotypes transition(M1 to M2)and inhibiting the process of EMT.