深Ⅱ度烫伤大鼠创面血管内皮细胞增殖与凋亡的变化在创伤修复中的作用

目的观察大鼠深Ⅱ度烫伤创面愈合过程中创基微小血管内皮细胞增殖与凋亡的变化特征,探讨血管的形成与退缩在创伤修复中的作用。方法利用大鼠5%深Ⅱ度烫伤模型,将72只Wistar大鼠随机分为正常对照和单纯烫伤两组。于伤后0.5,1,3,7,14d和21d采集创面皮肤标本,行HE染色,并用免疫组织化学技术检测创面组织真皮中血管内皮细胞PCNA和TUNEL的表达变化规律。结果深Ⅱ度烫伤的大鼠伤后3d,伤区出现少量的肉芽组织,7d时肉芽组织已充满伤区,再上皮化速率为30%,14d的再上皮化率达70%,至21d,伤口完全闭合,真皮内小血管的数量减少。大鼠烫伤后3d,伤区基底的真皮组织内出现PCNA阳性的血管内皮细胞,随后阳性表达逐渐增多,14d时达到高峰。至伤后21d,PCNA的阳性表达略有下降。而创伤愈合初期罕见TUNEL阳性的细胞,21d时,TUNEL标记阳性的细胞显著增多。结论烫伤大鼠创面中血管内皮细胞的增殖与凋亡活动与创面的愈合进程有密切的关系。血管形成与退缩在时序上的协调变化是组织正常修复的重要步骤。

Study on proliferation and apoptosis of vascular endothelial cells in granulation tissue after partial thickness scald injury

Objective To observe the changes of microvascu lar endothelial cells proliferatio n and apoptosis after 5%TBSA deeper partial thickness scald injury,and to explo re the effects of vascularization an d vascular regression on the early an d late stages of wound healing and during the remodeling phase.Methods 72Wistar rats were subjected to a 5percent partial thickness scald injur y,and divided randomly into two groups as follows:(1)normal control(n=36);(2)injured control group(n=36),then divided further into 0.5,1,3,7,14d and 21d post-burn groups,respectively.Hi stomorphometric changes of granula tion tissue formation and reepithelialization throughout healing were ob-served.Immunohistochemistry staining and TUNEL assays were performed to evaluate the changes of prolifera tive and apoptotic vascular en-dothelial cells in the wound site.Results A little capillary arose at 3days aft er thermal injury and thereafter gra dually increased.The max-imum increase in microvessel density was observed between 7and 14days after injury.The reepithelializatio n rate reached 30%and 70%from 7to 14days after thermal injury,wound closure has completed before21days post-burn.PCNA(proliferating cell nuclear antigen)im-munoreactive positive vascular endothelial cells were found in vessel-rich granulation tissue at 3days after thermal injury,and gradually in-creased thereafter,it peaked at 14d post-burn,then began to decreased a t 21days after thermal injury.A few T UNEL signal-positive vascular endothelial cells were detected in t he early stages of wound healing.How ever,apoptotic vascular endothelial cells increased significantly on21days post-burn.Conclusions The proliferation and apoptosis activities of vascular endothelial cells may be related to the process of wou nd healing.The relationship between a ngiogenesis and vascular regressio n may play an important role in normal tissue repair.