过氧亚硝基阴离子在大鼠糖尿病性白内障形成中的作用及葛根素的对抗作用

目的探讨过氧亚硝基阴离子(ONOO-)在糖尿病大鼠白内障形成中的作用,以及葛根素的对抗作用.方法将72只健康无热原Sprague-Dawley(SD)雄性大鼠均分为对照组、链脲佐菌素(STZ)组及治疗组,使用STZ制作STZ组和治疗组大鼠糖尿病模型,治疗组大鼠腹腔注射葛根素.分别于实验20、40及60 d检查大鼠的全身情况和晶状体形态;光镜下观察晶状体上皮细胞(LEC)的形态;同时使用流式细胞仪检测LEC中凋亡细胞的数量和百分率,以及ONOO-标志物--硝基酪氨酸(NT)阳性细胞的荧光强度和数量;采用免疫印迹法检测NT蛋白质在晶状体中的表达.结果实验20、40及60 d,对照组大鼠晶状体均透明,治疗组大鼠晶状体仅轻度混浊,STZ组晶状体混浊明显且逐渐加重;光镜下LEC形态对照组无改变,治疗组仅轻度改变,STZ组明显改变.实验20、40及60 d,凋亡细胞数量和百分率治疗组和STZ组与对照组比较,治疗组与STZ组比较,差异均有显著意义(P＜0.05);NT阳性细胞的荧光强度和数量治疗组和STZ组与对照组比较,治疗组与STZ组比较,差异均有显著意义(P＜0.05);治疗组和STZ组LEC凋亡情况的变化趋势与NT阳性细胞的荧光强度和数量的改变情况基本相同.各组均可见NT蛋白质表达;实验20、40及60d,NT蛋白质表达水平治疗组和STZ组与对照组、治疗组与STZ组比较,差异均有非常显著意义(P＜0.001).结论ONOO-参与介导大鼠糖尿病性白内障的形成,是白内障氧化应激损伤机制中不可忽视的因素之一.葛根素具有抗氧化作用,对于治疗大鼠早期糖尿病性白内障有一定效果.(中华眼科杂志,2004,40311-316)

Peroxynitrite-induced formation of diabetic cataract and its prevention by puerarin in rat

OBJECTIVE: To investigate the effect of peroxynitrite on the formation of diabetic cataract and its reversal by puerarin. in rat. METHODS: Normal Sprague-Dawley (SD) rats were equally divided into control group, streptozotocin group (STZ) and treatment group. STZ and treatment group were treated with STZ to establish animal model of diabetic rat cataract and in treatment group puerarin was given by peritoneal injection. General condition and lens shape of rats were examined at 20th, 40th, 60th day respectively. Lens epithelial cells (LEC) were observed with optical microscope. percentage of apoptotic cells, and fluorescent intensity of positive cells for nitrotyrosine (NT) which is the symbol of peroxynitrite were tested by flow cytometry. The expression of NT in the lens was analyzed by Western blot analysis. RESULTS: On 20th, 40th, 60th day of the experiment, clear, mild and severe lens opacity were found in control group, treatment group, and STZ group respectively and the lens opacity was gradually increased in all of rats included in the study. Under optical microscope, no changes were presented in control group, but mild changes were showed in treatment group and remarkable changes were found in STZ group. On all the specified days, distinguishable differences were found in the amount and percentage of apoptotic cells compared with that of control group in treatment group and STZ groups as well as between treatment and STZ groups (P < 0.05). There was significant increase in the fluorescent intensity and amount of NT in treatment and STZ groups compared with that of control group (P < 0.05), and the similar results were revealed between treatment group and STZ. The amount of expression of NT protein at different time points in different groups as described above was also significant difference (P < 0.001). CONCLUSIONS: Peroxynitrite plays an important role in the formation of diabetic rat cataract and is a participant in the pathogenesis of oxidative stress induced cataract. Puerarin is an effective antioxidative agent in the treatment of early diabetic rat cataract.