钙蛋白酶Ⅱ在萘性白内障氧化损伤中的作用

Effect of calpainⅡon oxidative damage in naphthalene-induced cataract

目的通过对萘性白内障氧化损伤及钙蛋白酶Ⅱ活性的研究,揭示钙蛋白酶Ⅱ在白内障中的作用。方法 30只150 g雌性SD大鼠被随机分成对照组和萘组。每周进行裂隙灯照相及灰度分析;第9周实验结束时进行血浆及晶状体中还原型谷胱甘肽(GSH)、丙二醛(MDA)、细胞内外Ca2+的检测,通过酪蛋白的水解程度检测钙蛋白酶Ⅱ活性的变化。结果第3周、第6周及第9周萘组皮质灰度值分别为51.98±3.17、52.19±2.96、53.61±3.79,对照组分别为69.47±3.13、81.36±3.25、98.17±3.86,自第3周起2组差异具有统计学意义(P<0.01)。第3周、第6周及第9周萘组核灰度值分别为55.76±3.95、55.98±3.14、56.41±2.96,对照组分别为58.67±3.02、65.13±3.21、69.48±2.83,自第3周起2组差异具有统计学意义(P<0.01)。第9周时,萘组血浆及晶状体中GSH水平低于对照组,而MDA明显高于对照组,差异具有统计学意义(P<0.05)。第9周时,萘组细胞内外Ca2+水平明显高于对照组,而钙蛋白酶活性明显高于对照组,差异具有统计学意义(P<0.05)。结论钙蛋白酶Ⅱ的活性升高在白内障的氧化损伤中起到重要作用。

Objective To study the oxidative damage and the activity of calpainⅡin naphthalene-induced cataract in order to clarify the possible mechanism for these changes.Methods Thirty female Sprague-Dawley rats weighted 150 g were randomly divided into two groups： the control group and the naphthalene group.Cataracts were induced by oral administration of 1 g naphthaleneper kilogram body weight per day.The development of naphthalene-initiated cataract was monitored every week by slit lamp microscopy for 9 weeks, then the concentrations of reduced glutathione （ GSH） and malondialdehyde （MDA） in rat lenses were measured to determine the role of oxidative stress in cataract induction .The total concentrations of Ca2＋were measured by atomic absorption spectrometry and the intro-cell Ca2＋were measured by co-focal microscopy.The activity of calpainⅡwas assayed fluorometrically with fluorescence-labeled casein.Results The cortex gray scales of the naphthalene group was 51.98 ±3.17, 52.19 ±2.96 and 53.61 ±3.79 at 3,6 and 9 weeks after the treatment respectively, and the cortex gray scales of the control group was 69.47 ±3.13, 81.36 ±3.25 and 98.17 ±3.86 at 3, 6 and 9 weeks respectively.The nucleus gray scales of the naphthalene group was 55.76 ±3.95, 55.98 ±3.14 and 56.41 ±2.96 at 3, 6 and 9 weeks after treatment respectively, and the nucleus gray scales of the control group was 58.67 ± 3.02, 65.13 ±3.21 and 69.48 ±2.83 at 3, 6 and 9 weeks respectively.The lenses of rats fed with naphthalene exhibited higher light scattering than those of rats fed without naphthalene from 3 weeks after the treatment （P〈0.01）.There were significant differences in GSH and MDA concentrations of plasma and lenses between the naphthalene group and the control group at 9 weeks after the treatment （P〈0.05）.The activity of calpainⅡwas increased in naphthalene-induced cataract at 9 weeks after the treatment （P〈0.05）.Conclusions The activity of calpainⅡwas raised by naphthalene, which might play important role in the oxidative damage in cataract.