Effect Of Topical Application Of Recombinant Human Epidermal Growth Factor At The Early Phase Of Wound Healing On Expression Of Epidermal Growth Factor Receptor In Deep Second-degree Scald Wound Of Rat

Background Recombinant human epidermal growth factor(rhEGF) hadbeen used in clinic for many years. Many animal experiments and clinictests had showed that rhEGF could accelerate wound healing anddeclined the hyperplasia of scar, but the mechanism of rhEGF whichused in wound healing is still not clear enough.Objective To investigate the effect of topical appilication ofrecombinant human epidermal growth factor(rhEGF) at the early phase ofwound healing on expression of epidermal growth factor receptor(EGFR)in deep second-degree scald of rat, and explore the mechanism of rhEGFwhich can accelerate wound healing and decline the hyperplasia of scar.Methods A total of64male Wistar rats weighing (195.34±6.26)g wererandomly divided into2groups(groups A and B, n=32).4rats wererandomly selected from two groups respectively before the remainderswere placed in80℃hot water for6seconds to prepare deep second-degree scald wounds on the back skin. The wounds of group Awere spayed physiological saline at150U/cm~2and applied1％silversulfadiazine cream; the group B were applied1％silver sulfadiazinecream after spayed rhEGF at150U/cm~2, all the wounds were suturedfixation with aseptic dressings within24hours after models preparation,and then do the same things at each day. The wound healing rate wasevaluated at3,7,10,14, and21days after injured. The expression ofEGFR protein was determined by Western blot at0,1,3,5,7,10,14,21days after operation.Result The deep second-degree scald model of rat had been establishedwith pathology. The wound healing rates were no significant differencebetween the two groups at3days(P＞0.05). The wound healing rate ingroup B was significantly higher than in group A at7,10,14, and21days(P＜0.01). Western blot showed that the expression of EGFR protein oftwo groups were very low at1days after injured, showing no significantdifference between group A and B (P＞0.05)； it gradual increased after1d,and reached the maximum level at7days， showing significantdifference between group A and B(P＜0.01). After reached themaximum level, the expression of EGFR protein of the two groups startedto gradual decline, however, the down-regulation of EGFR protein ofgroup B was faster than A, and reached a minimum level at14days,showing significant difference between the two groups(P＜0.01). After 14days, the expression of EGFR protein in group B gradual increasedagain, and approached the normal level(0d) at21days.Conclusion Topical application of rhEGF at the early phase ofwound healing can produce an influence for the expression of EGFRand accelerate obviously wound closure on deep second-degree scaldwound of rate.