碘酸钠诱导非渗出型年龄相关性黄斑变性模型的研究

Effects of hydralazine on NaIO_3 -induced rat retinal pigment epithelium degeneration

目的：研究10g/L胼酞嗪滴眼液对剂量为35mg/kg的NaIO3诱导的大鼠RPE变性的对抗作用。方法：经舌下静脉予Brown Norway大鼠分别注射不同剂量的NaIO3及生理盐水,注射3,7,14及28d后测量ERG的a、b、c、FO及LP波,同时进行眼底彩照和眼底荧光血管造影检查。用光学显微镜或自体荧光平片对部分大鼠进行组织学研究。在体外培养RPE-19细胞,观察不同浓度的NaIO3对细胞的影响并测其细胞增殖率。经舌下静脉予BrownNorway大鼠注射剂量为35mg/kg的NaIO3。NaIO3组大鼠注射NaIO3后用生理盐水点眼,10g/L胼酞嗪＋NaIO3组大鼠注射NaIO3后用10g/L胼酞嗪滴眼液点眼,对照组不注射NaIO3,用生理盐水点眼,皆为3次/d,连续点4wk,然后测ERGc波。结果：注射NaIO3后,高剂量组如30、40和60mg/kgNaIO3组的各种ERG波的振幅明显降低,低剂量组则变化不大。眼底彩照显示注射NaIO3后3d30mg/kg组出现部分视网膜坏死,视网膜坏死程度与注射后时间及注射量呈正相关,低剂量组没有明显改变。平片显示,注射NaIO3后3d30mg/kg组及更高剂量组单层RPE细胞出现坏死。组织学研究提示,注射NaIO330mg/kg组和低剂量组未发现明显变化。体外实验发现,浓度≥30mg/LNaIO3组RPE-19细胞增殖率降低。注射剂量为35mg/kgNaIO3后4wk,和对照组相比,NaIO3组大鼠ERGc波显著降低到对照组的31%（P〈0.01）。10g/L胼酞嗪＋NaIO3组和NaIO3组相比,大鼠ERGc波显著升高到对照组的50%（P〈0.05）。结论：NaIO3诱导的PRE细胞凋亡受剂量和时间的双重影响。剂量为30-40mg/kgNaIO3适用于非渗出型年龄相关性黄斑变性的体内造模。胼酞嗪可能延缓非渗出型年龄相关性黄斑变性的发展进程,可能用于治疗非渗出型年龄相关性黄斑变性。

AIM： To study the effects of 10g/L hydralazine eye drops on 35mg/kg NaIO3-induced degeneration in rat eyes. METHODS： Various doses of NaIO3 and/or saline alone were injected into Brown Norway rats from hypoglossal vein. After 3, 7, 14 or 28 days of injection, ERG a-, b-, c- wave, fast oscillation （FO） and light peak （LP） were measured along with retinal colored pictures and fluorescein angiography taken. Some rats were chosen to study the histology of retinas by light microscopy and autofluorescence of retina flatrnounts. Different concentrations of NaIO3 were given to RPE-19 cells, and cell proliferation rate was measured. For hydralazine study, 35mg/kg NaIO3 was injected into Brown Norway rat from hypoglossal vein. NaIO3 group was treated with saline alone after NaIO3 injection, 10g/L hydralazine ＋ NaIO3 group was treated with 10g/L hydralazine eyedrops after NaIO3 injection whereas normal group was treated with saline alone without NaIO3 injection. All eyedrops were instilled locally 3 times a day for 4 weeks and ERG c-wave was measured at the end of 2 and 4 weeks. RESULTS： After NaIO3 administration, the amplitude of all ERG waves fell markedly in large dose groups at 30, 40 or 60mg/kg NaIO3. Not many changes were observed in groups treated with 〈 30mg/kg NaIO3. Some retinal necrosis appeared from 3 days post-injection （PI） in 30mg/kg NaIO3 group, which became more serious in larger dose groups or longer treatment time, but no apparent change was found in smaller dose groups. Similarly, on the retina flatmount, RPE monolayer showed necrosis from 3 days PI in the 30mg/kg NaIO3 and larger dose groups. On histological examination, no significant change was seen in 30mg/kg NaIO3 and lower concentration groups. In cell culture experiment, changes were found in RPE-19 cells proliferation rate with a concentration of NaIO3 at 30mg/L or higher. In hydralazine experiments, 4 weeks after injection of NaIO3, ERG c-wave fell markedly in NaIO3 group to 31% of control group （ P 〈 0.01 ）. The ERG c-wave of hydra- lazine ＋ NaIO3 group fell only to 50% of control group （P〈0,05）, This was a61% reversal of the c-wave of NaIO3 treated group. CONCLUSION ： RPE degeneration induced by NaIO3 was both dose and time dependent. Around 30 to 40 mg/kg NaIO3 would be the optimal to be used as a non-exudative age-related macular degeneration rat model. Hydralazine may postpone the development of non-exudative agerelated macular degeneration.