血管紧张素Ⅱ受体在深Ⅱ度烧伤大鼠创面愈合过程中的表达

The expression of angioteusin Ⅱ receptors during wound healing in rat model of partial thickness cutaneous thermal injury

目的观察血管紧张素（Ang）Ⅱ 1型（AT1）和2型（AT2）受体在烧伤创面愈合过程中的表达及其与细胞增殖和凋亡的关系。方法在大鼠深Ⅱ度烧伤后即刻、3、7、14和21d取创面皮肤标本，采用免疫荧光组织化学染色法检测AT1和AT2的表达；采用增殖细胞核抗原（PCNA）标记和原位末端转移酶标记技术（TUNEL）染色法观察细胞增殖和凋亡。结果在正常皮肤，AT1和AT2表达强度较弱。但伤后第7天表达达高峰，14d降低，AT1的表达下调更明显。烧伤后7dPCNA阳性细胞数最多，14d后降低。烧伤后7～14dTUNEL阳性细胞数维持在较高水平，随后下降。结论烧伤愈合过程中AT1和AT2的表达具时空特性，这种变化与创面修复细胞增殖和凋亡密切相关。

Objective -To detect the spatial-temporal expression characteristic of both angiotensin U type 1 receptor （AT1） and angiotensin Ⅱ type 2 receptor （AT2） receptors, and explore the possible link between the expression of angiotensin Ⅱ （ Ang Ⅱ ） receptor and activity of cell proliferation and apop- tosis in rat model of partial thickness thermal injury. Methods The samples were obtained from deep par- tial thickness thermal injury skin in Wistar rats, and unjuried skin in normal Wisrar rats, respectively. Thirty-six male Wistar rats were divided randomly into two groups as follows ： （ 1 ） normal control group （n = 6） ; （2） injured group： that was further subdivided into subgroups of immediate, 3rd day, 7th day, 14th day and 21st day after injury, respectively （n =30）. Immunofluorescence staining was used to exam- ine the expression of AT1 and AT2 receptors in topical skin. Proliferating cell nuclear antigen （PCNA） la- beling index and TdT-mediated dUTP nick end labeling （TUNEL） staining were used to evaluate the cellular proliferation and apoptosis in burned skin. Results In the normal skin, the expression of both AT1 and AT2 receptors was mainly located in epidermal keratinocytes and dermal vessel walls. The expression of AT1 and AT2 receptors was increased after thermal injury, peaking at the 7th day postburn. Thereafter the expression of AT1 and AT2 receptors was reduced, and the reduction of AT1 receptor expression seemed to be more significant than AT2 receptor. Cell proliferation was increased in burned sites, peaking at the 7th day after burn, and then decreased. Apoptosis was also increased after burn, reaching a peak at the 7th day postburn. Apoptosis was decreased at the 21st day after burn. Conclusion These results indicate that Ang Ⅱ via AT1 and AT2 receptors might be involved in the regulation of cellular proliferation and apoptosis during wound healing.