Lajko Michelle, Cardona Herminio J, Taylor Joann M, Farrow Kathryn N, Fawzi Amani A
Department of Ophthalmology, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America.
Department of Pediatrics, Feinberg School of Medicine at Northwestern University, Chicago, Illinois, United States of America.
PLoS One. 2017 Jul 3;12(7):e0180384. doi: 10.1371/journal.pone.0180384. eCollection 2017.
To investigate the impact of photoreceptor oxidative stress on photoreceptor degeneration in mice carrying the rd8 mutation (C57BL/6N). We compared the hyperoxia-induced proliferative retinopathy (HIPR) model in two mouse strains (C57BL/6J and C57BL/6N). Pups were exposed to 75% oxygen, starting at birth and continuing for 14 days (P14). Mice were euthanized at P14, or allowed to recover in room air for one day (P15), seven days (P21), or 14 days (P28). We quantified retinal thickness and the length of residual photoreceptors not affected by rosette formation. In addition we explored differences in retinal immunostaining for NADPH oxidase 4 (NOX4), Rac1, vascular endothelium, and activated Mϋller cells. We analyzed photoreceptor oxidative stress using DCF staining in cross sections and quantified NOX4 protein levels using western blotting. C57BL/6N mice in HIPR showed increased oxidative stress, NOX4, and Rac1 in the photoreceptors at P14 and P15 compared to C57BL/6J. In addition, we observed significant progression of photoreceptor degeneration, with significantly accelerated rosette formation in C57BL/6N under HIPR, compared to their room air counterparts. Furthermore, C57BL/6N under HIPR had significantly thinner central retinas than C57BL/6J in HIPR. We did not find a difference in vascular disruption or Mϋller cell activation comparing the two strains in hyperoxia. In HIPR, the C57BL/6N strain carrying the rd8 mutation showed significantly accelerated photoreceptor degeneration, mediated via exacerbated photoreceptor oxidative stress, which we believe relates to Rac1-NOX dysregulation in the setting of Crb1 loss-of-function.
为了研究光感受器氧化应激对携带rd8突变的小鼠（C57BL/6N）光感受器退化的影响。我们比较了两种小鼠品系（C57BL/6J和C57BL/6N）中的高氧诱导增殖性视网膜病变（HIPR）模型。幼崽从出生开始暴露于75%氧气中，并持续14天（P14）。在P14对小鼠实施安乐死，或使其在室内空气中恢复1天（P15）、7天（P21）或14天（P28）。我们对视网膜厚度以及未受玫瑰花结形成影响的残留光感受器长度进行了量化。此外，我们探究了视网膜中烟酰胺腺嘌呤二核苷酸磷酸氧化酶4（NOX4）、Rac1、血管内皮和活化的米勒细胞免疫染色的差异。我们在横切面上使用二氯荧光素（DCF）染色分析光感受器氧化应激，并使用蛋白质印迹法对NOX4蛋白水平进行量化。与C57BL/6J相比，处于HIPR模型中的C57BL/6N小鼠在P14和P15时光感受器中的氧化应激、NOX4和Rac1增加。此外，我们观察到光感受器退化有显著进展，与处于室内空气环境中的同类相比，HIPR模型下的C57BL/6N中玫瑰花结形成明显加速。此外，HIPR模型下的C57BL/6N的中央视网膜比HIPR模型下的C57BL/6J明显更薄。在高氧环境中比较这两个品系时，我们未发现血管破坏或米勒细胞活化存在差异。在HIPR模型中，携带rd8突变的C57BL/6N品系显示光感受器退化明显加速，这是由加剧的光感受器氧化应激介导的，我们认为这与Crb1功能丧失情况下Rac1-NOX失调有关。
