葛根素对糖尿病大鼠白内障过程中晶状体诱导型一氧化氮合酶的影响

Effects of puerarin on inducible nitric oxide synthase in lens during diabetic cataract in rats

目的 :观察大鼠糖尿病性白内障 (DC)晶状体诱导型一氧化氮合酶 (iNOS)基因表达变化及葛根素对DC的治疗作用。方法 :经腹腔注射链脲佐菌素 (STZ)复制大鼠DC模型。实验分为STZ组 (STZ ,4 5mg/kgbw ,ip)、葛根素组 (STZ +葛根素 ,14 0mg/kgbwip)和对照组 (等量生理盐水 ,ip) ,分别于实验第 2 0、4 0、6 0d摘取大鼠晶状体 ,用逆转录聚合酶链反应 (RT -PCR)、蛋白印迹 (Westernblot)和生化方法检测晶状体iNOSmRNA和蛋白表达及一氧化氮(NO)含量、一氧化氮合酶 (NOS)活性变化 ,观察晶状体损伤的宏观和微观病理变化。结果 :对照组大鼠晶状体透明 ,iNOSmRNA未见明显表达 ,蛋白呈微弱表达 ,NOS活性较低 ,NO含量较少。在DC形成过程中 ,晶状体出现混浊、晶状体上皮细胞 (LEC)有明显病变 ,并随病程延长而加重 ;晶状体iNOSmRNA和蛋白表达明显上调 ,NOS活性增强、NO生成增加 ,并呈现时间依赖性。用药 4 0 - 6 0d时葛根素组前述晶状体病理变化轻于STZ组 ,iNOSmRNA和蛋白表达明显低于STZ组 ,NOS活性及NO生成低于STZ组。结论 :在大鼠DC形成过程中晶状体iNOS基因表达上调、NO含量增加 ;葛根素可减轻晶状体损伤 ,机制可能与抑制iNOS基因表达、减少NO生成有关。

AIM: To study the changes of iNOS mRNA ,protein and the production of nitric oxide(NO) as well as whether puerarin regulates the expression of iNOS mRNA during the formation of diabetic rat cataract. METHODS: One hundred and eight Sprague-Dawley(SD) rats were randomly divided into three groups, thirty-six rats were taken as control group, seventy two rats were injected peritoneally with streptozotocin(STZ,45mg/kg) to establish animal model of diabetic cataract, and then divided into STZ (36) and puerarin(36) treatment groups. Morphologic changes of lens were observered with slit lamp and light microscope; Samples were taken at 20th, 40th, 60th day and the changes in iNOS mRNA and protein expression of lens epithelium cells(LEC)as well as production of NO and NOS activity were determined with reverse transcription -polymerase chain reaction(RT-PCR), western blot, and biochemical method ,respectively. RESULTS: Morphologyic changes of LEC, up-regulation of iNOS mRNA and iNOS protein as well as increase in NO production and NOS activity in the LEC were observered during the formation of rat diabetic cataract. Compared with TZ group, puerarin treatment group showed distinctly down-regulation of iNOS mRNA and iNOS protein and decrease in NO production and NOS activity as well as attenuation of morphologic changes. CONCLUSIONS: There are morphologic changes of LEC and up-regulation of iNOS mRNA and as well as increase in NO production and NOS activity in the LEC during the formation of diabetic rat cataract , and treatment with puerarin can reverse the above changes.