活体视神经示踪剂锰离子对兔视网膜毒性的研究

目的 研究Mn2+作为视神经活体示踪剂对兔视网膜的毒性作用.方法 60只青紫兰兔120眼随机分为5组,分别单眼玻璃体腔中注入MnCl210、15、20、30、40 mmol/L 25μl.术前及术后7 d、28 d行眼底彩色照相、荧光素眼底血管造影、闪光视网膜电图(F-ERG)检测,并摘除眼球行视网膜光学显微镜和电子显微镜检查.对不同时间点实验组与对照组的F-ERG b波振幅进行比较,行重复测量的方差分析.结果 15 mmol/L浓度组注药前、注药后7及28 d F-ERG b波振幅分别为337、189、317μV,组间比较差异有统计学意义(F=20.43,P<0.05).注药后7 d F-ERG b波振幅降低,28 d b波振幅恢复正常;≥20 mmol/L浓度组注药后7 d F-ERG b波振幅降低,至28 d b波振幅未见恢复.光学显微镜及透射电子显微镜观察,≥20 mmol/L浓度组注药后各时间点均有视网膜结构异常改变.结论 MnCI2作为视神经活体示踪剂,浓度≤15 mmol/L仅引起视网膜功能可逆性改变;当浓度≥20 mmol/L视网膜出现功能及形态学损害.

Evaluation of toxicity of manganese ions to rabbit retina

Objective To research the Mn2+ toxicity in vivo rabbit retina. Mn2+ is used as a tracer in MRI. Methods It was an experimental study. Sixty pigmented rabbits (120 eyes) were divided into 5 groups randomly. Manganese chloride solution 25 μl of 10, 15, 20, 30, 40 mmol/L were injected intravitreally in one eye of each rabbit respectively as 5 experimental groups ( n = 12). The saline (0.9% ) 25μl was injected intravitreally in other eye of each rabbit as control group (60 eyes). After intravitreal injections, all eyes were examined by color fundus camera, fluorescent angiography, flash electroretinography, light microscopy, and thansmission electron microscopy on the 0th, 7th, and 28th day. Results On the 7th day after intravitreal injection, the average of the F-ERG b-wave amplitude was reduced significantly from 337 μV to 189 μV in the group of 15 mmol/L ( F = 20.43 ,P <0.05) , but the amplitude was returned to normal on the 28th day. On the 7th day after intravitreal injections, the F-ERG b-wave amplitude was reduced significantly in the group of ≥20 mmol/L, and the amplitude was not returned to normal on the 28th day. There were abnormal changes in the structure of the retina in ≥20 mmol/L group at difference time after intravitreal injections. Conclusion MnCl2 as a tracer in vivo optic nerve, the concentration of ≤15 mmol/L caused only reversible changes in retinal function; The concentration of ≥20 mmol/L appears, damages in retinal function and morphology appeared.