Abstract
Purpose :
This study explores the differential effects of oxygen concentration on vascular regression and regeneration, with a focus on the interaction between vascular structure and astrocyte expression using the oir mouse model.Retinal blood vessels and astrocytes form a cohesive unit, which astrocytes envelop the vessels, and both pericytes and endothelial cells contribute to the vascular structure.
Methods :
Following to the established OIR protocol, BL6/J mice were exposed to a 75±5% oxygen environment for three days starting at postnatal day 10 (P10), followed by observation under room air conditions. The mouse retinas were extracted just before and after oxygen exposure at P10,p13 and two weeks post-exposure at P27. The entire vascular structure was examined through immunostaining with endothelial cell marker (CD31) and pericyte marker (NG2). Astrocyte activity was assessed using GFAP immunostaining. Observations were conducted using a confocal microscope FV3000 (Olympus, Tokyo, Japan), and image analysis was performed using ImageJ software . <div id="gtx-trans" style="position: absolute; left: 557px; top: 95.9583px;"> <div class="gtx-trans-icon"> </div> </div>
Results :
In the areas of retinal vascular regression immediately following oxygen exposure, a more pronounced regression of NG2 compared to CD31 was observed in terms of area (6.2±2%). Additionally, a decrease in GFAP expression was noted (82.3±9.6%). During the two-week recovery in room air, NG2 exhibited significant elongation beyond CD31 in regenerating vessels. Notably, NG2 formed a unique monofilamentous network, unlike CD31. A reduction in GFAP expression was observed during the hyperoxic phase, which reverted to baseline levels during the room air phase. <div id="gtx-trans" style="position: absolute; left: 575px; top: 75.1667px;"> <div class="gtx-trans-icon"> </div> </div>
Conclusions :
NG2 tends to precede hyperoxia exposure in both vascular regression and subsequent vascular regeneration. The reversible astrocytic response highlights the potential for adaptive mechanisms in retinal pathologies. These insights pave the way for future research into targeted treatments for retinal diseases, emphasizing the importance of interactions between pericytes and astrocytes in vascular health.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.