Chen Yan, Chen Ping, Masayuki Hanaoka, Peng Hong, Yunden Droma, Keishi Kubo
Department of Respiratory Medicine, the Second Xiangya Hospital, Central-South University, Changsha 410011, China.
Zhonghua Nei Ke Za Zhi. 2010 May;49(5):380-4.
To investigate whether the endothelin (ET) receptor antagonists have protective role in the development of emphysema.
Sprague-Dawley rats (n = 24) were divided into four groups: control group, cigarette smoke extract (CSE) group, BQ123 group and Bosentan group. CSE was injected intraperitoneally once a week for three weeks and BQ123 and Bosentan were administered daily for the same duration. TdT-mediated dUTP nick end labeling (TUNEL) was performed to observe the deoxyribonucleic acid (DNA) damaged cells and the expression of caspase-3 was determined by immunohistochemistry and Western blot. Matrix metalloproteinase-2 (MMP-2) and MMP-9 activities were investigated by gelatin zymography and tumor necrosis factor α (TNFα) and interleukin-1ß (IL-1ß) concentrations were measured by enzyme linked immunosorbent assay (ELISA).
We confirmed the emphysematous destruction in the lungs of experimental rats induced by the intraperitoneal injection of CSE within 3 weeks. The mean lining interval (MLI) and damage index (DI) were significantly increased in the CSE group compared with control group. However, the MLI and DI were significantly decreased in the BQ123 and bosentan groups compared with CSE rats (P < 0.01, respectively). The TUNEL-positive cells were markedly distributed in the peri-bronchioles, intra-alveoli, and septal areas of the emphysematous lungs in CSE rats comparing with the lungs of control rats. The apoptosis index (AI) was significantly higher in CSE group than control group. And the AI was significantly reduced in BQ123 group and bosentan group compared with that in CSE group. The caspase-3 positive cells were markedly distributed in the emphysematous lungs of CSE group comparing with the stained cells in the lungs of control rats. These positive cells were apparently reduced in the BQ123 and bosentan groups compared with the stained cells in CSE group. Comparing with the control group, expression of caspase-3 was prominently enhanced in CSE groups, but both BQ123 and bosentan treatments markedly inhabited the increases of the cleaved caspase-3 protein levels in rats injected with CSE. Rats injected with CSE showed increased MMP-2 and MMP-9 activities in their lung tissue homogenates and MMP-2 and MMP-9 activities were reduced significantly in both BQ123 and bosentan groups. The levels of TNFα and IL-1ß were significantly increased in the CSE group in comparison to those in controls. BQ123 and bosentan significantly prevented the increases of the levels of TNFα and IL-1ß in lungs of rats with injection of CSE.
ET-1 may have an important role in the pathological process of emphysema and ET receptor antagonists protect against the development of emphysema probably by decelerating apoptosis, inhibiting proteolytic enzyme activity and reducing inflammatory cytokine levels.
探讨内皮素（ET）受体拮抗剂在肺气肿发生发展过程中是否具有保护作用。
将24只Sprague-Dawley大鼠分为四组：对照组、香烟烟雾提取物（CSE）组、BQ123组和波生坦组。每周腹腔注射一次CSE，共注射三周；BQ123和波生坦每日给药，持续时间相同。采用TdT介导的dUTP缺口末端标记法（TUNEL）观察脱氧核糖核酸（DNA）损伤细胞，通过免疫组织化学和蛋白质印迹法检测半胱天冬酶-3（caspase-3）的表达。采用明胶酶谱法研究基质金属蛋白酶-2（MMP-2）和MMP-9的活性，通过酶联免疫吸附测定法（ELISA）检测肿瘤坏死因子α（TNFα）和白细胞介素-1β（IL-1β）的浓度。
我们证实了腹腔注射CSE 3周内可诱导实验大鼠发生肺气肿性破坏。与对照组相比，CSE组的平均内衬间隔（MLI）和损伤指数（DI）显著增加。然而，与CSE大鼠相比，BQ123组和波生坦组的MLI和DI显著降低（P均<0.01）。与对照大鼠的肺相比，TUNEL阳性细胞明显分布在CSE大鼠肺气肿肺的细支气管周围、肺泡内和间隔区域。CSE组的凋亡指数（AI）显著高于对照组。与CSE组相比，BQ123组和波生坦组的AI显著降低。与对照大鼠肺中的染色细胞相比，caspase-3阳性细胞明显分布在CSE组的肺气肿肺中。与CSE组的染色细胞相比，BQ123组和波生坦组的这些阳性细胞明显减少。与对照组相比，CSE组中caspase-3的表达显著增强，但BQ123和波生坦治疗均显著抑制了注射CSE大鼠中裂解的caspase-3蛋白水平的升高。注射CSE的大鼠肺组织匀浆中MMP-2和MMP-9的活性增加，而BQ123组和波生坦组中MMP-2和MMP-9的活性均显著降低。与对照组相比，CSE组中TNFα和IL-1β的水平显著升高。BQ123和波生坦显著抑制了注射CSE大鼠肺中TNFα和IL-1β水平的升高。
ET-1可能在肺气肿的病理过程中起重要作用，ET受体拮抗剂可能通过减缓细胞凋亡、抑制蛋白水解酶活性和降低炎性细胞因子水平来预防肺气肿的发生发展。
