蛋白激酶A在干扰素-γ抑制创面愈合和瘢痕形成中的作用

Activity of protein kinase A in IFN γeffecting wound healing and scar formation of rabbit ear

目的:观察干扰素γ(IFN-γ)用于兔耳伤口肉芽组织和瘢痕组织后蛋白激酶A(ProtinaseA,PKA)活性变化及对伤口愈合和瘢痕形成影响,探讨PKA的信号转导作用。方法:用32P掺入法测定使用IFN-γ前后兔耳伤后3,6,11～16d(上皮化时),以及上皮后14,30,45和60d组织的PKA活性,观察伤口愈合时间和瘢痕变化。结果:上皮化时肉芽组织和伤口周边组织的PKA活性高于正常皮肤犤(1.5±0.6)pmol/min·mg,t=3.76,P<0.001和(1.4±0.5)pmol/min·mg,t=2.96,P<0.01犦。IFN-γ延迟创面愈合约1.5d(t=2.64,P=0.01),同时进一步活化PKA:肉芽组织在伤后6d和上皮化时犤(1.6±0.6)pmol/min·mg,t=2.59,P<0.05和(1.8±0.7)pmol/min·mg,t=2.92,P<0.01犦和周边组织上皮化时犤(1.7±0.6)pmol/min·mg,t=2.42,P<0.05犦高于对照。增生性瘢痕组织的PKA活性仅在上皮化时升高犤(1.5±0.5)pmol/min·mg,t=2.26,P<0.05犦,非增生性瘢痕组织的PKA活性在上皮化时犤(1.4±0.5)pmol/min·mg,t=2.08,P<0.05犦和上皮化后14d犤(1.4±0.5)pmol/min·mg,t=2.08,P<0.05犦时较高;IFN-γ进一步升高上皮化时IFN-γ1组:犤(1.8±0.7)pmol/min·mg,t=2.92,P<0.01犦和伤后14d时非增生性瘢痕组织的PKA活性犤IFN-γ1组:(1.79±0.6)pmol/min·mg,t=2.59,P<0.05和IFN-γ2组:(

AIM:To investigate the signal mechanism of IFN γeffecting by observing the changes of activity of protein kinase A(PKA) in granulation tissue,wound margin tissue and scar tissue of rabbit ear and changes of wound healing and scar formation after using IFN γ. METHODS:IFN γwas applied on the wound and in the scar tissue of rabbit ear.PKA activity in the tissue at 3,6 and 11-16 days after the wound formation and at 14,30,45,and 60 days after wound epithelization were measured by phosphorus(32p) incoporation.The time of wound epithelization and scar changes were also observed. RESULTS:The PKA activity in granulation tissue and wound margin tissue(including 6 d after wound formation) from wound epithelization was obviously higher than that of normal skin[(1.5±0.6)pmol/min·mg,t=3.76,P< 0.001 and(1.4±0.5)pmol/min·mg,t=2.96,P< 0.01]. IFN γdelayed the wound healing about 1.5 d(t=2.64,P=0.01)and activated the PKA.IFN γincreased obviously PKA activity in granulation tissue at 6 d after wound formation[(1.6±0.6)pmol/min·mg,t=2.59,P< 0.05 and (1.8±0.7) pmol/min·mg,t=2.92,P< 0.01] and wound margin tissue from wound epithelization[(1.7±0.6) pmol/min·mg,t=2.42,P< 0.05] respectively.PKA activity of hypertrophic scar tissue from wound formation increased[(1.5±0.5)pmol/min·mg,t=2.26,P< 0.05] and so did non hypertrophic scar tissue from wound formation[(1.4±0.5)pmol/min·mg,t=2.08,P< 0.05] and 14 days after wound epithelization[(1.4±0.5)pmol/min·mg,t=2.08,P< 0.05]. IFN γincreased more from wound formation(IFN γgroup Ⅰ, [(1.8±0.7) pmol/min·mg,t=2.92,P< 0.01] and 14 days after wound,PKA activity of non hypertrophic scar tissue[IEN γgroup Ⅰ(1.79±0.6) pmol/min·mg,t=2.59,P< 0.05,and group Ⅱ(1.8±0.6) pmol/min·mg,t=2.55,P< 0.05] was no significant difference from that before wound epithelization(P >0.05). 60 days after wound epithelization,the number of hyperplastic scar(8 or 9) using IFN γwas obviously lower than the control(24) (χ2 =13.33,11.61,P< 0.001),and there was no difference between them. CONCLUSION:The increased PKA activity in granulation tissue and wound margin tissue by IFN γmay be related to delaying wound healing.The increased PKA activity in non hypertrophic scar tissue by IFN γsuggests that PKA may mediate the signal of IFN γinhibiting scar hyperplasia.