莱菔硫烷对链脲佐霉素诱导的大鼠糖尿病白内障的治疗作用

Effects of sulforaphane on streptozotocin-diabetic cataract of rats

目的探讨莱菔硫烷（Sulforaphane，SFN）对链脲佐霉素诱导的大鼠糖尿病白内障的治疗作用。方法将72只雄性sD大鼠随机分为正常对照组、模型组、SFN低剂量干预组、SFN中剂量干预组、SFN高剂量干预组和苄达赖氨酸（bendazacly-sine，BDL）组，每组12只，后5组腹腔一次性注射链脲佐菌素（65mg·kg^-1）建立糖尿病白内障模型，从造模成功当日开始，SFN低、中、高剂量干预组分别给予50mg·kg^-1、100mg·kg^-1、200mg·kg^-1 SFN灌胃，BDL组以200mg·kg^-1BDL灌胃，其余2组用同体积的生理盐水，每天1次，治疗12周后，测定空腹血糖水平，裂隙灯观察大鼠晶状体变化并对其混浊度进行分级，分离晶状体并制备成匀浆液，测定丙二醛（malondialdehyde，MDA）含量及超氧化物歧化酶（superoxide dismutase，SOD）、谷胱甘肽过氧化物酶（glutathione-peroxidase，GSH-Px）、过氧化氢酶（catalase，CAT）活性，EuSA检测糖基化终末产物（advanced glycosylation end products，AGEs）含量，行Western-blotting检测醛糖还原酶（aldose reductase，AR）表达。结果用药后12周，SFN中、高剂量干预组大鼠空腹血糖明显低于模型组（均为P〈0．05），而SFN低剂量干预组、BDL组仍处于高血糖水平，与模型组比较，差异均无统计学意义（均为P〉0．05）。正常对照组大鼠晶状体透明，无混浊发生；而模型组大鼠晶状体出现雾状混浊、核混浊，分级为Ⅲ-Ⅴ级，其混浊度显著高于正常对照组（P〈0．01）。与模型组比较，SFN中、高剂量干预组晶状体混浊度等级差异明显减轻（均为P〈0．05），而SFN低剂量干预组、BDL组晶状体混浊度等级与模型组相比，差异均无统计学意义（均为P〉0．05）。与正常对照组比较，模型组大鼠晶状体组织中MDA含量升高，而SOD、GSH-Px、CAT活性降低，差异均有统计学意义（均为P〈0．01）。经中、高剂量SFN或BDL处理后，MDA含量较模型组减少（均为P〈0．05），SOD、GSH-Px、CAT活性较模型组增加（均为P〈0．05）。而SFN低剂量干预组上述指标与模型组相比，差异均无统计学意义（均为P〉0．05）。模型组大鼠晶状体组织中AGEs含量较正常对照组升高（P〈0．01）；相对于模型组，经中、高剂量SFN处理12周后，AGEs含量明显减少（均为P〈0．05）；而SFN低剂量干预组、BDL组AGEs含量与模型组比较，差异均无统计学意义（均为P〉0．05）。运用Western-blotting检测各组大鼠晶状体组织AR蛋白表达，结果显示：正常对照组AR蛋白呈低水平表达，模型组AR蛋白表达明显上调，与正常对照组比较，差异有统计学意义（P〈0．01）；相对于模型组，经中、高剂量SFN或BDL处理后，AR蛋白表达水平降低（均为P〈0．05），而SFN低剂量干预组AR蛋白表达水平与模型组比较，差异无统计学意义（P〉0．05）。结论SFN对链脲佐菌素诱导的大鼠糖尿病白内障有治疗作用，其机制可能与增强抗氧化能力、抑制AGEs产生及下调AR表达有关。

Objective To observe the effects of sulforaphane （SFN） on strepto- zotocin （STZ） -induced diabetic cataract of rats, and explore its related mechanisms. Methods Seventy-two male SD rats were randomly divided into normal control group, model group, SFN low-dose intervention group, SFN middle-dose intervention group, SFN high-dose intervention group, and bendazac lysine （BDL） group, 12 rats in each group. Rats in the latter 5 groups were intraperitoneally injected with STZ （65 mg·kg^-1 ） to establish diabetic cataract model. From the day of model establishment, rats in SFN low-, middle- and high-dose intervention groups were intragastrically treated with 50 mg·kg^-1 , 100 mg·kg^-1 and 200 mg·kg^-1 SFN, respectively. Rats in BDL group were intragastrically administrated with 200 mg·kg^-1 BDL. However, rats in nor- mal control and model groups were treated with the same volume of normal saline. Af- ter 12 weeks of drug treatment, fasting blood glucose was examined among groups. Eyes of rats were examined with slit lamp microscope on dilated pupils. Initiation and pro- gression of lenticular opacity were assessed according to the Azuma system. The lens were removed and prepared to homogenate. Subsequently, the content of malondialde- hyde （MDA） as well as the activities of superoxide dismutase （SOD）, glutathione-per- oxidase （GSH-Px） and catalase （CAT） were detected. Advanced glycosylation end products （AGEs） amount was measured using enzyme linked immunosorbent assay （ELISA）. In addition ,Western blotting was used to examine aldose reductase （AR） ex- pression. Results At 12 weeks after drug treatment, fasting blood glucose were signif- icantly decreased in the SFN middle- and high-dose intervention groups compared with the model group （ all P 〈 0.05 ）, but there was no statistical difference in the SFN low- dose intervention group and BDL group compared with the model group （ all P 〉 0.05 ）. The lens in the normal control group were clear without opacification, but the model group had haze and nuclear opacification with degree Ⅲ- Ⅳ, and the opacification de- gree was higher than the normal control group （P 〈 0.01 ）. Compared with the model group,the opacification degree in the SFN middle- and high-dose intervention groups were obviously decreased （ all P 〈 0.05 ）, but there was no statistical difference in the SFN low-dose intervention group and BDL group compared with the model group （all P 〉 0.05 ）. In comparison with normal control group ,the contents of MDA,AGEs and AR expression levels were increased, but SOD, GSH-Px and CAT activities were decreased in lens tissues of model group （ all P 〈 0.05 or 0.01 ）. Upon treatment with middle- and high-dose SFN ,the contents of MDA, GEs and AR expression levels were markedly re- duced while SOD, GSH-Px and CAT activities were obviously enhanced in lens tissues as compared to model group （ all P 〈 0.05 or 0.01 ）. There was no statistical difference in the above indexes of the SFN low-dose intervention group compared with the model group （ all P 〉 0.05 ）. Conelusion SFN may protect rats from STZ-induced diabetic cataract by enhancing anti-oxidative abilities, inhibiting AGEs production and down-reg- ulating AR expression.