微量元素铜/锌比值对糖尿病大鼠视网膜病变的影响

Effect of Trace Element Copper/zinc Ratio on Retina in the Diabetic Rats

目的探讨铜/锌(Cu/Zn)比值与糖尿病大鼠视网膜病变的关系,观察适量补Zn并使Cu/Zn比值下降对糖尿病大鼠视网膜病变的影响。方法将雄性SD大鼠40只随机分为四组,即正常对照组、模型对照组、实验Ⅰ组和实验Ⅱ组。按60 mg/kg体质量尾静脉注射链脲佐菌素(STZ)以制造糖尿病大鼠模型。实验Ⅰ组、Ⅱ组分别以葡萄糖酸锌每日Zn2+6 mg/kg体质量(浓度为0.12 mg/m l/kg)和每日Zn2+3 mg/kg体质量(浓度为0.06 mg/m l/kg)用水溶解后单笼喂养。模型对照组、正常对照组饮用自来水。实验周期3个月,采尾血测血糖(BS),再从颈总动脉取血分别测定血清Cu、Zn含量,并计算出Cu/Zn比值。双眼灌流后制作视网膜血管铺片,铺片行PAS染色,光镜下观察大鼠视网膜毛细血管结构。结果①实验Ⅰ组血清Zn和Cu/Zn比值接近或超过正常对照组,与模型对照组相比有显著性差异(P<0.01);而实验Ⅱ组的血清Zn和Cu/Zn比值与模型对照组相比差异无统计学意义。②视网膜血管铺片正常对照组可见毛细血管形态规整;模型对照组视网膜毛细血管形态发生改变,血管迂曲、扭结,部分血管闭塞。补充Zn剂后,实验Ⅰ组随着Cu/Zn比值的下降,其视网膜毛细血管形态改变较同一时期的模型对照组明显好转,而实验Ⅱ组视网膜毛细血管形态改变类似于模型组。结论对糖尿病大鼠,适量补充Zn剂使Cu/Zn比值下降,可减轻视网膜的毛细血管损伤。

Objective To study the correlation of trace element copper/zinc ratio and retina in the diabetic rats. To observe the effect and prevention foundation on retina in the diabetic rats after proper supplement of zinc which decreases the ratio of copper/zinc. Methods Divide 40 masculine adult SD rats into normal group, diabetes mellitus model group, the groups of experiment Ⅰ and Ⅱ, 10 rats in each group. Diabetes was induced with a single dose of 60 mg/kg of streptozotocin（STZ）. The groups of experiment Ⅰ and Ⅱ were fed in single boxes after taking oral glucose respectively; daily dose was Zn^2＋6 mg/kg（0.12mg/ml/kg） and Zn^2＋3 mg/kg（0.06 mg/ml/kg） dissolved in water. Model group and normal group drink running water. The period was beyond 3 months. Collect tail blood to measure blood sugar, collect blood from the main artery of the neck to measure the quantities of the serum Cu Zn and copper/zinc ratios. After irrigating two eyes, make retina blood capillary slides, which were stained by PAS, observe the structure of the retina in the adult rats through light-microscope. Results ①The serum Zn and the ratio of copper/zinc of the experiment group I are close to or beyond normal. There is obvious difference compared with model group（P 〈0.01）, but no difference compared with experiment group If.② Through normal contrast group of slides of retinal blood vessel, the regular state of capillary, the changes of state of retina capillary can be observed. The irregularity of capillary caliber and closed capillary can also be found. With the supplement of zinc dose and the reduction of copper/zinc ratio as for group Ⅰ, the changes of state of retinal capillary are obviously relieved compared with those in contrast groups in the same period. However, group Ⅱ remained unchanged. Conclusion To supplement zine dose properly and reduee the ratio of eopper/zine earl alleviate the damage of hyperglueose to the small blood vessels of retina. Therefore, the mierovessel of rats can be protected.