Genetical blockade of VEGFR1 signaling alleviates pathological angiogenesis.
(a) While abnormal αSMA+ cell migration and proliferation membrane-like structures with retinal detachment can be observed in both genotypes, pathological angiogenesis appears to be normalized N-PRβ-KO-Flt1TK−/− mice compared with N-PRβ-KO mice at 4 weeks. CD31+ blood vessels (cyan) and αSMA+ cells (red). (b) Whereas highly remodeled retinal vasculature is observed in N-PRβ-KO mice, relatively normal blood vessel sizes, vascular networks, and ECM deposition are observed in N-PRβ-KO-Flt1TK−/− mice at 4 weeks. CD31+ blood vessels (cyan) and collagen type IV deposition (magenta). (c and d) The N-PRβ-KO-Flt1TK−/− blood vessel area was significantly smaller than that of N-PRβ-KO mice and similar to that of WT mice (c). n = 16 randomly selected areas (20× objective lens) from 4 retinas collected from males and females. The blood vessel diameter of N-PRβ-KO-Flt1TK−/− retinas was significantly smaller than that of N-PRβ-KO retinas and was similar level to WT, but statistically significant (d). n = 160 randomly selected blood vessels (20× objective lens) from 4 retinas collected from males and females. (e and f) The collagen type IV deposition in N-PRβ-KO-Flt1TK−/− was significantly smaller than that of N-PRβ-KO mice and significantly larger than that of WT mice (e). n = 16 randomly selected areas (20× objective lens) from 4 retinas collected from males and females. The collagen type IV thickness from endothelial cell surface in N-PRβ-KO-Flt1TK−/− retinas was significantly smaller than that of N-PRβ-KO retinas and significantly larger than that of WT (f). n = 160 randomly selected blood vessels (20× objective lens) from 4 retinas collected from males and females. All values represent means ± SEM. ***, p < 0.001 vs. WT at the same time points, ###, p < 0.001 vs. N-PRβ-KO-Flt1TK−/−, $$$, p < 0.001 vs. WT. Scale bar = 500 μm (a), 100 μm (b). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)