Retinal thicknesses in WT and
KLKB1−/− mice were measured by SD-OCT at baseline (preinjection) and at 24 hours post intravitreal injection with VEGF or PBS vehicle. Representative retinal SD-OCT B-scans with segmentation of the retinal layers illustrating retinal thickness after intravitreal PBS or VEGF injections in WT and
KLKB1−/− mice are shown in
Figure 2A. Measurements of total retinal thickness (RPE to RNFL) and retinal segments are shown in
Supplementary Table S1. The total retinal thicknesses of WT and
KLKB1−/− mice at baseline were 204.8 ± 0.6 and 205.5 ± 0.9 μm, respectively (NS). At 24 hours post intravitreal injection, VEGF increased retinal thickness by 35.6 ± 3.5 μm (17.4%) and 20.0 ± 2.3 μm (9.7%) (
P < 0.001) in WT and
KLKB1−/− mice, respectively, compared with baseline thicknesses (
Fig. 2B). Intravitreal injection of PBS vehicle increased retinal thicknesses in WT mice by 6.6 ± 2.8 μm (3.2%) and
KLKB1−/− mice by 4.7 ± 1.4 μm (2.3%) (
Fig. 2B). Subtraction of the small injection/PBS effect on retinal thickness from the VEGF responses revealed 14.1% and 7.4% increases in VEGF-specific retinal thickening in WT and
KLKB1−/− mice, respectively. Vascular endothelial growth factor injection increased retinal layer thickness compared with baseline in WT mice by 15.9 ± 3.3, 7.7 ± 2.2, and 13.9 ± 2.4 μm (
P < 0.001) for inner plexiform layer (IPL)-RNFL, inner nuclear layer (INL), and outer nuclear layer (ONL) and in
KLKB1−/− mice by 8.4 ± 2.0 and 6.2 ± 1.8 μm (
P < 0.05) for IPL-RNFL and ONL, respectively (
Fig. 2C). The VEGF induction of retinal layer thickness in
KLKB1−/− mice was reduced by 47.2% and 44.9% (
ττ P < 0.001) for total (RPE-RNFL) and ONL and 49.5% and 58.3% (
τ P < 0.05) for IPL-RNFL and INL. No significant differences were observed in the RPE–inner segment (IS) layer among groups.