瘢痕组织中Caspase-3/8的表达与细胞凋亡

Expression of Caspase-3/8 during wound healing and its relation with cell apoptosis

目的：观察天冬酰胺特异性酶切的半胱氨酸蛋白酶成员caspase-3/8在瘢痕组织中的表达,了解caspase-3/8在瘢痕形成过程中诱导修复细胞凋亡的变化规律。方法：瘢痕标本来自烧伤后来我院进行整形手术的病人,同时取病人手术供皮区的正常皮肤作为对照。8例瘢痕组织标本(含2例愈合较为平坦的瘢痕和6例增生性瘢痕组织)被分成增殖期和成熟期两组。运用原位杂交和免疫组化法检测瘢痕及正常皮肤真皮内caspase- 3/8 mRNA及其蛋白的表达,并以TUNEL方法检测瘢痕及正常组织中的凋亡细胞。结果：瘢痕组织内caspase- 3/8mRNA及其蛋白的表达明显高于正常组织,增生性瘢痕组织的表达又强于较为平坦的瘢痕。同时组织中细胞凋亡的数目明显不同。瘢痕内的TUNEL标记阳性细胞数多于正常组织；增殖期瘢痕内的细胞凋亡的数目多于成熟期。增生性瘢痕与较平坦的瘢痕相比,增殖期TUNEL标记阳性的细胞多于平坦瘢痕,而成熟期两者无显著性差别。结论：伤口愈合过程中,caspase-3/8参与了修复细胞的凋亡括动,病理性的愈合结局与caspase-3/8表达密切相关。

Objective:To determine the expression of caspase-3/8 mRNA and proteins in scar tissue,and ob- serve the phenomenon of apoptosis associated with caspase—3/8 and its involvement in the process of scar forma- tion.Methods:The samples of scar were obtained from postburn patients undergoing plastic operation recently in our burn unit,and the samples of control were obtained from skin donor sites of the same patient respectively.All the scar samples(2 cases of normally healed flat scars and 6 cases of hyperplastic scar)were divided into two groups(P,proliferative stage＜12 months after healing;M,mature stage＞12 months after healing)according to the age of the scar.In situ hybridization and immunohistochemistry staining technique were employed to deter- mine the expression of caspase-3/8 mRNA and proteins in scar tissue and normal skin.TUNEL assay was per- formed to determine the number of apoptotic cells in scar and normal skin.Resnlts:The expression of caspase-3/8 mRNA and proteins in scar tissue was much stronger than that in normal skin,and cell positive expression was much stronger in hyperplastic scar than that in normally healed flat scars.Obvious difference in apoptotic cells was found between scars tissue and normal skin.The positive expression cells were much more abundant in hyperplas- tic scars than that in normal skin;the number of apoptotic cells was slightly greater in the proliferative stage than that in the mature stage.However,in proliferative stage,the number of TUNEL-positive cells was greater in hy- perplastic scar than normally healed flat scars.But in mature stage,no obviously differences in the number of TUNEL-positive cells were found between hyperplastic scar and normally healed flat scar.Conclusion:Apoptosis might be involved in reconstitution of dermal tissue,probably under the influence of caspase-3/8.The enhanced activity of caspase-3/8 might be related to the abnormal healing process.