NADPH氧化酶在鼓室硬化症大鼠模型中的表达

Expression of NADPH oxidase in a rat model of tympanosclerosis

目的研究NADPH氧化酶(NOX,NOX2及NOX3)在鼓室硬化症大鼠模型的中耳组织中的表达,探讨鼓室硬化症氧化性损伤的发生机制。方法 20只雄性、体重250~300 g的Spragua-Dawley大鼠随机分成两组(实验组15鼠30耳,对照组5鼠10耳):(1)实验组:鼓膜后上象限人工制造2 mm大小穿孔,连续饲养18 d;(2)对照组:不做任何处理,连续饲养18 d。造模完成后,利用内镜检查两组大鼠鼓膜形态;利用RT-PCR法检测NOX基因的表达;采用列联表二项分类逻辑回归分析,分析鼓膜穿孔和NOX基因表达的相关性以及鼓室硬化和两种NOX基因表达的相关性。结果实验组15只大鼠全部造模成功,对照组大鼠无一出现鼓膜钙化及浑浊;RT-PCR检验大部分实验组大鼠发现NOX2及NOX3基因同步表达;而对照组大部分大鼠NOX2及NOX3基因表达均为阴性,通过列联表二项分类逻辑回归分析,提示鼓膜穿孔可致NOX2及NOX3基因的表达增强(P<0.01),而NOX基因的激活与鼓室硬化症的发生相关,并具有统计学意义(P<0.01)。结论在穿孔导致的鼓室硬化症发病过程中,NOX是活性氧的来源之一,可能是导致鼓室硬化氧化性损伤发生的重要原因。

ObjectiveTo investigate the expressions of NADPH oxidases （NOX2 and NOX3） in an experimental rat model of tympanosclerosis and their possible roles in the oxidative damage of this disease.MethodsTwenty healthy, adult, male, Sprague-Dawley rats （40 ears） weighing 250-300 g, were randomly divided into two groups. Of them, 5 （10 ears） were chosen to serve as controls, and the other 15 （30 ears） were used in the experimental group. On the first day, rats in the experimental group received myringotomy to the superior-posterior quadrant of the tympanic membrane of both ears making a perforation of 2 mm diameter, while rats in the control group got no operation. All the rats received otoscopy and were sacrificed on the 18th day. Gene expressions of NOXs in middle ear tissue were detected by reverse transcription-polymerase chain reaction （RT-PCR）. Two-way contingency table logistic regression analysis was adopted to analyze the relationship between tympanic membrane perforation and expression of NOX genes as well as that between tympanosclerosis and expression of NOX genes.ResultsAt the 18th day，sclerotic changes （calcification and opacification） of tympanic membrane were observed in all the rats of the experimental group while no evidence of sclerotic changes in those of the control group. RT-PCR showed coincident expressions of NOX2 and NOX3 in most specimens of the experimental group with negative expressions in most specimens of the control group. Two-way contingency table logistic regression analysis revealed that tympanic membrane perforation may activate the expression of NOX genes （P〈0.01）, which may be related to the occurrence of tympanosclerosis （P〈0.01）.ConclusionIn the process of tympanosclerosis caused by tympanic membrane perforation, NOX may be an important source of reactive oxygen species which may induce oxidative damage of tympanosclerosis.