早期糖尿病大鼠光感受器超微结构变化

Ultrastructural changes of photoreceptors of early diabetic rats

目的探讨早期糖尿病视网膜病变光感受器超微结构变化。方法选择健康成年Ｗｉｓｔａｒ大鼠３２只，随机分成正常对照组、糖尿病１，３月和６月组。 ５５ ｍｇ／ｋｇ体重一次性腹腔内注射链脲佐菌素诱导大鼠糖尿病。取大鼠视网膜制备超薄切片，透射电镜观察并计算机图像分析。结果病程１月只见视杆细胞膜盘模糊不清，膜盘间隙略有扩大；病程３月时，膜盘间隙扩大明显，并发生局部断裂溶解。视杆细胞核固缩、异染色质浓集。视杆内节线粒体肿胀、甚至空泡变性。病程６月时，以上改变更加严重。结论糖尿病视网膜病变早期大鼠出现光感受器的形态变化，随病程进展，呈现逐渐加重的趋势。

Objective To investigate ultrastructural changes of photoreceptors in early diabetic retinopathy (DR). Methods 32 healthy adult Wistar rats were chosen and divided into normal control group,diabetes mellitus one month(DM 1), three-month(DM3 ) and six-month (DM6 ) group. Diabetic rats were induced by 55 mg/kg streptozotocin (STZ) once intraperitoneally. Superthin sections made from rat retinas were stained with heavy metals and observed under transmission electron microscope and then analyzed by electronic computer-picture analytical system. Results in DMI,membrane disks of rods were only obscure and their spaces were enlarged slightly. In DM3,the membrane disk spaces were enlarged obviously with breaking and dissolving locally;rod cell nuclei showed pyknosis and chromatin condensed; condrocytes of inner segments of rods swelled and even denatured. In DM6, all the above changes appeared more seriously. By computer-picture analyzing, the O/M values of DMI, DM3 and DM6 were 0.108±0.024,0.197±0. 140 and 0.247±0.107, respectively. Conclusion in the early stage of diabetic retinopathy,the morphological changes emerge in photoreceptors. The principal changes include membrane disks of rods being obscure, spaces enlarging and even breaking and dissolving locally, rod cell nuclei showing pyknosis and their chromatin condensing. Along with the progression of diabetic retinopathy I pathological alterations get worse gradually.