血管紧张素Ⅱ及其受体表达在创面愈合过程中的变化及作用

目的 观察创面愈合过程中血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)及其受体表达的动态变化,以及这种变化与创面愈合过程中细胞增殖和凋亡活动之间的关系,探讨AngⅡ在创面愈合过程中的可能作用.方法 建立小鼠背部全层皮肤缺损创面模型,于创面形成后第0、1、3、5、7、9、11、13、15天切取创面组织标本,用ELISA法检测创面局部组织AngⅡ产生的变化;采用BrdU及TUNEL染色检测创面细胞增殖和凋亡的变化;用免疫组织化学染色和RT-PCR检测创面局部组织AngⅡ受体AT1和AT2表达的组织细胞定位和mRNA水平的变化.结果 小鼠全层皮肤缺损创面局部组织AngⅡ、BrdU标记指数均在伤后逐渐增加,并于第7天达到峰值后即逐渐下降.TUNEL染色阳性细胞数在伤后即开始缓慢增加,并于创面完成上皮化后增加趋势更为明显.正常小鼠皮肤AT1和AT2受体在整个表皮层均有阳性表达,但在真皮层,AT1和AT2受体仅在微血管内皮细胞有阳性表达.AT1受体在角质形成细胞、成纤维细胞均有表达,阳性染色信号在伤后逐渐增加,在第7天最强,以后逐渐下降.AT2受体阳性染色信号也在伤后逐渐增加,7 d以后则逐渐下降.但当创面上皮化完成后,AT2受体阳性染色信号再次增加.RT-PCR结果 显示:AT1和AT2受体mRNA均有表达,AT1、AT2受体mRNA表达在伤后第7天均达到峰值,此后则逐渐下降,且AT2受体mRNA表达在创面上皮化完成后表达再次增加.结论 在创面愈合过程中,AngⅡ可能通过其产生及受体表达的变化调控创面的愈合及后期的塑形改建.AT1受体可能与细胞增殖活动密切相关;AT2受体可能与细胞凋亡及愈合过程中组织重建有关.

Abstract：

Objective This study was undertaken to observe the change in the local level of angiotensin Ⅱ (Ang Ⅱ) and the expression of its corresponding receptors AT1 and AT2 during wound healing, and explore the possible role of Ang Ⅱ in wound healing . Methods A model of full-thickness cutaneous wound was developed on the back of C57/BL6 mice. Specimens were taken from the wound of each mouse on the day 0, 1, 3, 5, 7, 9, 11, 13 and 15 after wounding. The change in the generation of Ang Ⅱ in wounded tissue during the healing process was detected with ELISA. The proliferation and the apoptosis of cells were detected by bromodeoxyuridine (Brdu) and terminal deoxyuncleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) method in wounded skin during the healing process, respectively. The cellular localization and the mRNA level change of Ang Ⅱ receptors in wounded tissue during healing were detected with immunostaining and RT-PCR. Results Ang Ⅱ produced in wounded skin was increased in the first 7 days to reach the peak, and then gradually decreased during wound healing. BrdU labeling index was increased gradually in the first 7 days to reach the peak, and then gradually decreased during wound healing. The number of TUNEL-positive cells was increased slowly in the first 7 days after wounding. The increase in the number of TUNEL-positive cells was more markedly after epithelization of the wound. In normal mice, AT1 and AT2 receptor were found positively expressed in the whole epidermal layer, while positive expression was only found in the endothelial cells of the capillary vessels within the dermal layer, and positive expression was also found in appendages of the skin, i.e. hair follicle, sweat gland and sebaceous gland respectively. Positive staining signal of both AT1 and AT2 receptors were increased in the first 7 days to reach the peak, then gradually decreased. Expression of AT2R was increased again following the epithelization of wound. The result of RT-PCR showed that the expression of both AT1 and AT2 receptors was detectable, and AT1 receptor was increased in the first 7 days to the peak, and then gradually decreased during wound healing, while AT2 receptor expression reached its peak value on day 7, then gradually decreased, and increased again following the epithelization of wound. Conclusions These results indicate that Ang Ⅱ participate in wound repair and related to remolding in the late stage of wound healing through the change in production of angiotensin Ⅱ and expression of AT1 and AT2 receptors. AT1 receptor might be closely associated with cell proliferation,while AT2 receptor might play a role in cell apoptosis and remolding during wound healing.

The change of angiotensin II production and its receptor expression during wound healing: possible role of angiotensin II in wound healing

Objective This study was undertaken to observe the change in the local level of angiotensin Ⅱ (Ang Ⅱ) and the expression of its corresponding receptors AT1 and AT2 during wound healing, and explore the possible role of Ang Ⅱ in wound healing . Methods A model of full-thickness cutaneous wound was developed on the back of C57/BL6 mice. Specimens were taken from the wound of each mouse on the day 0, 1, 3, 5, 7, 9, 11, 13 and 15 after wounding. The change in the generation of Ang Ⅱ in wounded tissue during the healing process was detected with ELISA. The proliferation and the apoptosis of cells were detected by bromodeoxyuridine (Brdu) and terminal deoxyuncleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) method in wounded skin during the healing process, respectively. The cellular localization and the mRNA level change of Ang Ⅱ receptors in wounded tissue during healing were detected with immunostaining and RT-PCR. Results Ang Ⅱ produced in wounded skin was increased in the first 7 days to reach the peak, and then gradually decreased during wound healing. BrdU labeling index was increased gradually in the first 7 days to reach the peak, and then gradually decreased during wound healing. The number of TUNEL-positive cells was increased slowly in the first 7 days after wounding. The increase in the number of TUNEL-positive cells was more markedly after epithelization of the wound. In normal mice, AT1 and AT2 receptor were found positively expressed in the whole epidermal layer, while positive expression was only found in the endothelial cells of the capillary vessels within the dermal layer, and positive expression was also found in appendages of the skin, i.e. hair follicle, sweat gland and sebaceous gland respectively. Positive staining signal of both AT1 and AT2 receptors were increased in the first 7 days to reach the peak, then gradually decreased. Expression of AT2R was increased again following the epithelization of wound. The result of RT-PCR showed that the expression of both AT1 and AT2 receptors was detectable, and AT1 receptor was increased in the first 7 days to the peak, and then gradually decreased during wound healing, while AT2 receptor expression reached its peak value on day 7, then gradually decreased, and increased again following the epithelization of wound. Conclusions These results indicate that Ang Ⅱ participate in wound repair and related to remolding in the late stage of wound healing through the change in production of angiotensin Ⅱ and expression of AT1 and AT2 receptors. AT1 receptor might be closely associated with cell proliferation,while AT2 receptor might play a role in cell apoptosis and remolding during wound healing.