遗传性视网膜病变模式大鼠的氧诱导视网膜病变观察

目的:探索遗传性视网膜病变模式大鼠的氧诱导视网膜新生血管特点。方法:将新生(生后7d)的SD大鼠、CSNB大鼠和RCD大鼠各1窝每窝(即每组)6只暴露于800±20mL/L氧浓度环境中持续饲养5d,然后再回到正常氧环境条件饲养5d;对照组为以上3种品系同龄新生鼠各1窝,每窝(即每组)各6只置于正常氧环境中饲养17d作为对照。在第18d时将所有幼鼠行心脏墨汁灌注,取出两侧眼球,其中1眼用于视网膜铺片了解视网膜血管形态的改变,另1眼用于组织切片观察并统计突破视网膜内界膜的血管内皮细胞核的数目。结果:在正常饲养环境下,RCD大鼠视网膜血管网稀疏,SD大鼠CSNB大鼠视网膜血管未见明显异常。在氧诱导下,各实验组大鼠视网膜血管正常网络状结构受到破坏,结构稀疏,血管迂曲、收缩或扩张,部分血管出现闭塞,其中SD大鼠、CSNB大鼠视网膜有出血点,甚至片状出血。组织切片显示对照组的SD大鼠中偶见突破内界膜的内皮细胞核,其他两组均未见。实验组中SD大鼠、CSNB大鼠和RCD大鼠3种品系中均可见较多的突破内界膜内皮细胞核,计数结果分别为24.10±2.49,38.20±10.47,68.00±3.06,与同品系的对照组有显著性的差异(P<0.01);与不同品系的实验组比较也均有显著性差异(P<0.01)。结论:氧诱导的新生大鼠视网膜新生血管与品系有关,视网膜退行性病变大鼠仍可诱导出视网膜新生血管,且严重程度可能与感光细胞的功能有关。

Oxygen-induced retinopathy in retinal degeneration model rats

AIM:To explore the characteristics of oxygen-induced retinal neovascularization in retinal degeneration model rats.METHODS:Neonate 7-day-old SD rats(6),congenital stablenary night-blindness(CSNB) rats(6),retinal cone degeneration(RCD) rats(6) were exposed to(800±20)mL/L oxygen for 5 days and then to the room air for another 5 days.Age-matched 3 broods of corresponding animals without high oxygen exposure were used as controls.At the 18th day,the hearts of all rats were perfused with ink,and then their bilateral eyeballs were enucleated.One was used as retinal preparation to assess the morphological change of retinal vessels,the other was used as histological section to observe and count the endothelial cell nuclei of new vessels extending from the retina into the vitreous in 4μm sagittal sections.RESULTS:Under normoxia-raising condition,the retinal vascular net was sparse in RCD rats.The endothelial cells were sporadically observed in SD rats,but not in CSNB rats based on tissue sections.After high-concentration oxygen exposure,the retinal blood vessels were constricted,occluded in three rat strains of experimental groups.The retinal non-perfusion area and even hemorrhage could be observed in SD rats and CSNB rats.Tissue sections showed that endothelial cell nuclei breaking inner limiting membrane were occasionally seen in SD rats of control group,but not found in two other broods of rats.In experimental groups,the mean number of endothelial cell nuclei extending from retina to vitreous per section in SD rats,CSNB rats and RCD rats were 24.10±2.49,38.20±10.47,68.00±3.06 respectively.There were significant differences between control groups and experi-mental groups(P<0.01)in terms of the same rat strain.Moreover,there were also significant differences between different rat strains in experimental group(P<0.01).CONCLUSION:The retinal neovascularization could be induced by oxygen in retinal degeneration rats and might be related to the retinal photoreceptor cell function.The oxygen-induced retinal neovascularization in neonate rats is associated with the strain of rats.