The Effect Of USP4-mediated TGF-β Signaling Pathway On Formation Of Hypertrophic Scar In Rabbit Ears

Hypertrophic scars are comman clinically pathological scars,and can be visible、elevated、itchy and painful,causing serious functionl disability. Recent studies have shown that TGF-β signaling pathway plays a key role in the formation of hypertrophic scars,and other studies have found that USP4 can enhance the level of the TGF-β signaling pathway,but in the hypertrophic scars formation,there is no report about the role of USP4 for the TGF-β signaling pathway.Our previo us studies show that USP4 gene significantly higher in the hypertrophic scars tissue, and was positively correlated with TβRI,futher study using USP4 inhibitors in the scar fibroblasts can significantly reduce the expression of TβRI,suggesting that USP4 ma y influence the formation of scar tissue through regulating the TGF-β signaling pat hway. Research shows that in the process of wound repair,the rh TGF-β3 could significantly inhibit the formation of hypertrophic scars.In the experiment Ⅰ,we applied rh TGF-β3 in the rabbit ears modle of hypertrophic scars to explore whether USP4 and TβRI in the rabbit ears hypertrophic scars high expression,and study its influence on USP4 and TβRI.Vialinin A,is an inhibitor of USP4,In the experiment Ⅱ,we applied Vialinin A to inhibit USP4,exploring the effects of interferencing USP4 on hypertrophic scars formation. We detected the expression of TβRI、TGF-β1、Smad7 in the rabbit ears scar tissue,so as to investgate the possible ways of USP4.In order to futher explore the effect on hyperplastic scar formation and explore new methods for the treatment of hyperplastic scar in animal level.This paper consists of two parts:Part Ⅰ: Study on the expression of USP4 and TβRI on the hypertrophic scars of rabbit earsObjective : To investi gate whether USP4 and TβRI in the rabbit ears hypertrophic scars high expression,study whether USP4 plays an important part in rabbit ears hypertrophic scar formation.Methods:Ten New Zealand white rabbits were used to establish rabbit ears hypertrophic scar models.The left and right ear of each individual were randomly divided either experimental group or control. Rabbits in experimental group were injected with rh TGFβ3, while rabbits in the control group were injected with the same dose of saline. The resurfacing skin was resected for sectioning and staining respectively 30 、60 days after the wound healed. We compared the change of scar appearance between groups.The resurfacing skin of different groups was resected for HE and immunohistochemical detection, so as to study and analysis the expression of USP4 and TβRI and SEI in the experimental group and control rabbit ears scar tissue.Results:1.In contrast with the control, the experimental group can significantly improve the appreance of the rabbit ears scar tissue and reduce the SEI, The difference of SEI between experimental group and control was statistically significant(P < 0.05). 2.The immunohistochemical results show in contrast with the control, the USP4 and TβRI in the hypertrophic scar of rabbi t ear from experimental group were reduced. The difference between experimental group and control at the same piont was statistically significant(P < 0.05).Conclusion:1. rh TGF-β3 could significantly inhibit hypertrophic scar formation. 2.The expression of USP4 and TβRI in the rabbit ears hypertrophic scar were high and USP4 was closely related to TβRI.Part Ⅱ:Effect of Vialinin A inhibited USP4 on the formation of hypertrophic scars in rabbit ears.Objective:To investigate the effects and possible mechanism of appling USP4 inhibitors Vialinin A to inhibit USP4 on rabbit ears hypertrophic scar formation. To study the prevention role of inhibited USP4 on rabbit ears hypertrophic scar and find new solutions for clinical treatment of hypertrophic scar.Methods:Ten New Zealand white rabbits were used to establish rabbit ears hypertrophic scar models.The left and right ear of each individual were randomly divided either dose group or control. Once the wound healed,the dose group were injected with Vailinin A, while the control group were injected with the same dose of saline.The resurfacing skin was resected for sectioning and staining respectively 30 、60 days after the wound healed.We compared the change of scar appearance between groups,and then the resected scar tissue wan handled with HE staining 、immunohistochemical detection and Western blot,so as to study and analysis the expression of TβRI、TGF-β1、Smad7 and SEI in the dose group and control rabbit ears scar tissue.Results:1.In contrast with the control, the dose group can significantly improve the appreance of the rabbit ears scar tissue and reduce the SEI, The difference of SEI between dose group and control at the same piont was statistically significant(P < 0.05). 2.The immunohistochemical results show that in contrast with control, the range of positive staining USP4 was small and the depth was shallow, inducing that USP4 expression was restrained. 3.Western blot results show that in contrast with the control,the expression of TβRI and TGF-β1 were reduced in the dose group,the expression of Smad7 was increased.The difference of TβRI、TGF-β1 and Smad7 between dose group and control at the same piont was statistically significant(P < 0.05).Conclusion:1.Vialinin A could interferent USP4, reduce its expression, inhibit the formation of hypertrophic scar in rabbit ears. 2.The inhibitory function of ihbited USP4 on the hypertrophic scar may be associated with down-regulated expression of TβRI、TGF-β1,as well as improved expression of Smad7. 3.USP4 may be one of the treatment targets of hypertrophic scar.The main puepose of the present study was to observe the effects of USP4 on the formation of hypertrophic scar in animal level.The animal models of this study were rabbit ear hypertrophic scar animal model which is comparative mature.We detected the SEI in rabbit ears,histopathology,the expression of TβRI、TGF-β1、Smad7 in rabbit ears scar tissue after the application of Vialinin A,so as to study the role of inhibited USP4 on rabbit ears hypertrophic scar and find new solutions for clinical treatment of hypertrophic scar.