糖尿病兔晶状体后囊膜混浊模型的建立

Establishment of model of diabetes and lens posterior capsule opacification induced by alloxan in rabbit

背景实验性糖尿病动物模型的制作是对糖尿病性眼病进行实验研究的关键环节，目前国内普遍应用的方法是链脲佐菌素和四氧嘧啶（ALX）注射，但前者价格昂贵，后者造模过程中动物的死亡率较高。目的探讨ALX注射制作糖尿病兔晶状体后囊膜混浊（PCO）模型并降低死亡率的方法，并观察高血糖对晶状体PCO形成的早期影响。方法将清洁级健康新西兰雄性大白兔40只随机分为2组；其中20只兔经耳缘静脉一次性注射ALX90mg／kg建立糖尿病模型作为高血糖组，另20只兔以同样的方法注射等量生理盐水作为正常血糖组。药物注射后2周时高血糖组兔血糖升高到12．0mmol／L以上可判断为建模成功，2组分别行兔右眼透明晶状体囊外摘出术并对晶状体PCO进行分级。于术后第6、10、14天取眼球，应用免疫组织化学法观察增生细胞核抗原（PCNA）在后囊膜晶状体上皮细胞（LECs）中的表达情况。结果ALX注射后糖尿病兔的成模率为70％。术后第6、10、14天时，高血糖组兔体质量均明显低于正常血糖组，但血糖明显高于正常血糖组，差异均有统计学意义（P〈0．05）。高血糖组术后14d时观察的3只兔中，2只兔出现后囊膜2级混浊，另1只兔出现1级混浊。正常血糖组术后14d时观察的3只兔后囊膜均出现1级混浊。免疫组织化学染色显示，术后第10天高血糖组可见PCNA在LECs的细胞核中表达，但正常血糖组未见PCNA的表达。术后第14天时高血糖组PCNA增生指数为0．86±0．04，明显高于正常血糖组的0．25±0．03，差异有统计学意义（t=-16．171，P=0．000）。结论90mg／kg的ALX静脉注射能形成稳定的糖尿病兔PCO模型；高血糖是促进PCO发生发展的重要因素之一。

Background The establishment of diabetic animal model is a crucial step for the study about diabetic eye diseases. At present,the main modeling method include the injection of streptozotocin and alloxan. But the shortcoming of the former is an expensive price, and that of the later is high death rate of animals. Objective This experiment was to discuss the way which decrease the death of alloxan-injected animal and explore the effects of high blood glucose on the posterior capsular opacification （PCO）. Methods Forty clean heahhy male New Zealand white rabbits were randomly divided into 2 groups. 90mg/kg of alloxan were injected via ear vein once in 20 rabbits to create the diabetic animal models, and the equivalent amount of normal saline solution was injected at the same way as normal blood glucose group. The successful models were selected in the animals with the blood glucose level over 12.0 mmol/L two weeks later, and PCO of lens were graded based on the method of Odrich under the slit lamp. Extracapsular lens extraction was then performed on the fight eye of rabbits in both groups,and the posterior capsules were obtained from these eyes at the 6th, 10th and 14th days after operation. The expression of proliferating cell nuclear antigen （PCNA） in posterior capsular lens epithelial cell was detected by immunohistochemistry. Results The modeling successful rate was 70% after injection of alloxan. The body weight of rabbits in high blood glucose group was significantly lowed and the blood glucose was significantly elevated in comparison with normal blood glucose group （all P〈0. 05 ）. Two weeks after surgery,2 eyes occurred 2 grade of PCO and only one eye showed the 1 grade of PCO in the high blood glucose group. However, 1 grade of PCO was found in 3 eyes in the normal blood glucose group. Biopsy revealed that PCNA was positively expressed in the cell nuclei of LECs in high blood glucose group rather than the normal blood glucose group from the 10th day after surgery. The proliferation index of PCNA was 0. 86±0. 04 and 0. 25±0. 03 respectively in high blood glucose group and normal blood glucose group, showing a significant difference between them （t =-16. 171 ,P = 0. 000）. Conclusion Stable diabetic models of rabbits can be created by intravenous injection of 90 mg/kg alloxan. High blood glucose level is one of the important factors for the development of PCO.