钙蛋白酶Ⅱ在萘性白内障氧化损伤中的作用

摘要

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。（中国眼耳鼻喉科杂志，2014，14：273-277）%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.