Figure 3.

Genetic deletion of A₁Rs reduced hypoxia-induced retinal vascular regression and cellular apoptosis at P12. (A) Retinal blood vessels of both WT and KO groups were visualized by isolectin B4 staining of whole-mount retinas at P12 of OIR. The whole retinal surface is shown by white dotted line. Avascular area is indicated as yellow. Scale bar: 500 μm. (B) Avascular area (%) was quantified as a percentage of the whole retinal surface (n = 7 retinas from seven WT mice and n = 9 retinas from nine A₁R KO mice). Data are presented as the mean ± SEM. *P < 0.05, Student's t-test. (C, D) The apoptotic cells in retinal cross-sections of WT and A₁R KO mice were detected by TUNEL staining at P12 of OIR. TUNEL-positive cells are indicated by yellow arrows. TUNEL signals were detected mainly in INL and ONL layers of retina in both WT and A₁R KO mice. Coimmunostaining of TUNEL and CD31 (a marker for endothelial cell) revealed that CD31⁺ cells (white arrowhead) were largely segregated from the TUNEL signal (yellow arrowhead) with little coimmunostaining of TUNEL/CD31 (yellow arrow). Scale bar: 20 μm. (E) The TUNEL-positive cells of WT and A₁R KO groups were quantified. Data are presented as mean ± SEM. *P < 0.05 comparing A₁R KO group with WT group (n = 6 retinas from six WT mice and n = 6 retinas from six A₁R KO mice).