Department of Radiology, Stony Brook University, Stony Brook, NY, United States of America.
Research Imaging Institute, University of Texas Health San Antonio, San Antonio, TX, United States of America.
PLoS One. 2022 Mar 25;17(3):e0266192. doi: 10.1371/journal.pone.0266192. eCollection 2022.
To test the hypothesis that mild chronic hyperoxia treatment would improve retinal function despite a progressive decline in ocular blood flow in the DBA/2J mouse model of glaucoma.
DBA/2J mice were treated with chronic mild hyperoxia (30% O2) beginning at 4.5 months of age or were untreated by giving normal room air. Retinal and choroidal blood flow (RBF and ChBF, respectively) were measured at 4, 6, and 9 months of age by MRI. Blood flow was additionally measured under hypercapnia challenge (5% CO2 inhalation) to assess vascular reactivity. Intraocular pressure (IOP) was measured using a rebound tonometer at the same time points. Scotopic flash electroretinograms (ERGs) were recorded at 9 months of age.
Both ChBF and RBF were reduced and significantly affected by age (p < 0.01), but neither were significantly affected by O2-treatment (p > 0.05). ChBF significantly increased in response to hypercapnia (p < 0.01), which was also unaffected by O2-treatment. Significant effects of age (p < 0.001) and of the interaction of age with treatment (p = 0.028) were found on IOP. IOP significantly decreased in O2-treated mice at 6 months compared to 4 months of age (p < 0.001), while IOP trended to increase with age in untreated mice. The amplitude of the b-wave from ERG was significantly increased in O2-treated DBA/2J compared to the untreated mice (p = 0.012), while the a-wave and oscillatory potentials were not significantly affected (p > 0.05).
This study investigated the effects of chronic mild hyperoxia on retinal function and on retinal and choroidal blood flow in a mouse model of glaucoma. Retinal function was improved in the O2-treated mice at late stage, despite a progressive decline of RBF and ChBF with age that was comparable to untreated mice.
检验以下假说，即慢性轻度高氧处理可改善视网膜功能，尽管在 DBA/2J 青光眼模型中眼血流呈进行性下降。
4.5 月龄时，DBA/2J 小鼠开始接受慢性轻度高氧（30%O2）治疗或给予正常室内空气作为未治疗对照。4、6、9 月龄时通过 MRI 测量视网膜和脉络膜血流（RBF 和 ChBF）。通过 5%CO2 吸入评估血管反应性，同时测量血流。在相同时间点使用回弹眼压计测量眼内压（IOP）。9 月龄时记录暗适应闪光视网膜电图（ERG）。
ChBF 和 RBF 均降低且受年龄显著影响（p<0.01），但均不受 O2 处理显著影响（p>0.05）。ChBF 对高碳酸血症显著增加（p<0.01），这也不受 O2 处理影响。IOP 受年龄显著影响（p<0.001）和年龄与处理的相互作用显著影响（p=0.028）。与 4 月龄相比，6 月龄时 O2 处理小鼠的 IOP 显著降低（p<0.001），而未处理小鼠的 IOP 随年龄增加呈上升趋势。与未处理小鼠相比，O2 处理的 DBA/2J 小鼠的 ERG 中 b 波振幅显著增加（p=0.012），而 a 波和振荡电位未受显著影响（p>0.05）。
本研究调查了慢性轻度高氧对青光眼模型中小鼠视网膜功能以及视网膜和脉络膜血流的影响。尽管 RBF 和 ChBF 随年龄呈进行性下降，与未处理小鼠相当，但 O2 处理小鼠的视网膜功能在晚期得到改善。
