Vldlr-/- mice
Our group is the first to identify and validate Vldlr-/- (Very low density lipoprotein receptor knockout) mice as a genetic mouse model for Age-Related macular Degeneration (AMD). Charlesson has patents pending on the use of these mice for ophthlamic drug screening.
Vldlr-/- mice present with many cardinal features of AMD, including choroidal neovascularization, over-expression of VEGF, increased vascular leakage, upregulation of inflammatory factors, and cone photoreceptor degeneration.
Choroidal Neovascularization in the Vldlr-/- eye. (A,B) Choroidal-RPE flat mounts following intravascular filling with fluorescein-conjugated high molecular weight dextran at age P12. Unlike wt (A) which has an intact RPE layer, the neovasculature already penetrated from the choroid through Bruch’s membrane and the RPE (large fluorescent spots in B) in Vldlr-/- mice (red arrows). This assay provides a quick and robust means for quantifying a therapeutic effect on alleviating CNV.
Retinal Vascular Leakage in Vldlr-/- mice. (A,B) FITC-dextran (molecular weight of 2000 kDa) was injected into the left ventricle. The fundus image was taken 3 min after the injection in wt (A) and Vldlr-/- (B) mice. (C,D) After an intravenous injection of FITC-BSA, the retina was dissected, fixed immediately and flat-mounted. Retinal vasculature was visualized under a fluorescent microscope. Leakage of FITC-dextran or FITC-BSA from retinal vasculature was observed in the Vldlr-/- retina both in fundus images and in flat-mounted retinas (B & D, respectively), but not in the wt retina (A & C).
Over-expression of VEGF in Vldlr-/- mice. (A) Equal amount of eyecup proteins was separately blotted with antibodies for VEGF and for VEGFR2. The membranes were stripped and re-blotted with an anti-β-actin antibody. (B) VEGF monomer (23 kDa) and dimer (46 kDa) were semi-quantified by densitometry, normalized by β-actin levels and expressed as the relative ratio of wt to Vldlr-/- (mean±SD, n=3). (C) Real-time RT-PCR showed elevated VEGF mRNA levels in the Vldlr -/- retinas and choroids (expressed as the wt to Vldlr-/- ratio, mean±SD, n=3). (D) VEGFR2 levels were measured by Western blot analysis.
