碘酸钠诱导大鼠视网膜损伤的病理改变和SOD、CAT的变化

目的: 探讨不同剂量碘酸钠诱导大鼠视网膜损伤过程中的病理形态改变及抗氧化系统中超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性的改变。方法: SD大鼠80只,随机分为4组(每组20只),即40 mg/kg、50 mg/kg、60 mg/kg碘酸钠造模组和正常对照组。在造模后第1、4、7、14 d取大鼠右眼进行病理检查;取左眼视网膜,检测SOD和CAT的活性。结果: 病理结果显示,与对照组比较,第1 d,40 mg/kg和50 mg/kg碘酸钠造模组视网膜各层未见损伤,60 mg/kg碘酸钠造模组出现视网膜色素上皮层损伤、外核层细胞排列紊乱;第4、7、14 d,各剂量组均出现明显损伤,且损伤程度比第1 d和对照组明显加重,呈现外核层细胞波浪状改变和外核层厚度减少(P＜0.05或P＜0.01)。生化检测结果显示,与对照组比较,第1、4 d,60 mg/kg碘酸钠造模组视网膜组织SOD、CAT的活性均显著下降(P＜0.05);第7、14 d,各剂量组视网膜SOD、CAT活性均呈明显下降趋势(P＜0.05或P＜0.01)。结论: 40 mg/kg、50 mg/kg和60 mg/kg的碘酸钠均可导致大鼠视网膜色素上皮层和外核层细胞损伤,并使大鼠视网膜抗氧化系统受损。碘酸钠用量越大,视网膜细胞损伤出现时间越早、程度越重。

Pathological changes and activity of SOD and CAT in the damaged retina induced by sodium iodate in rats

AIM: To investigate the pathological changes and the activity of superoxide dismutase(SOD) and catalase(CAT) in the damaged retina induced by sodium iodate in rats.METHODS: The SD rats were randomly divided into 4 groups, 40 mg/kg, 50 mg/kg and 60 mg/kg of sodium iodate treatment groups and control group. Rats were sacrificed on day 1, 4, 7, 14 after the injection of sodium iodate. The right eyeballs were immediately enucleated and fixed. Routine pathological examination was carried out. And the retinal tissues were extracted from the left eyeballs. The activity of SOD and CAT were measured by photometry. RESULTS: The pathological examination showed that 40 mg/kg and 50 mg/kg of sodium iodate didnt induce damage of retina on day 1, while 60 mg/kg of sodium iodate induced the damage of retinal pigment epithelium and disarrangement of outer nuclear layer compared with control group. Each dosage on day 4,7,14 induced more significant damage than that on day 1, with waveform damage changes and decreasing depth of outer nuclear layer (P<0.05 or P<0.01). As the photometry test showed, compared with control group, 60 mg/kg of sodium iodate induced significant decrease of SOD and CAT activity on day 1 and day 4 (P<0.05); each dosage induced significant decrease of SOD and CAT activity on day 7 and day 14 (P<0.05 or P<0.01). CONCLUSION: This suggests that all of 40 mg/kg, 50 mg/kg and 60 mg/kg of sodium iodate could induce damage of retinal pigment epithelium and outer nuclear layer, and they could also break down the antioxidative system. Sodium iodate could have the dose-dependent effect on the onset time and the level of retinal damage.