Early vascular and neuronal changes in a VEGF transgenic mouse model of retinal neovascularization.
OBJECTIVE
To investigate early retinal changes in a vascular endothelial growth factor (VEGF) transgenic mouse (tr029VEGF; rhodopsin promoter) with long-term damage that mimics nonproliferative diabetic retinopathy (NPDR) and mild proliferative diabetic retinopathy (PDR).


METHODS
Rhodopsin and VEGF expression was assessed up to postnatal day (P)28. Vascular and retinal changes were charted at P7 and P28 using sections and wholemounts stained with hematoxylin and eosin or isolectin IB4 Griffonia simplicifolia Samples were examined using light, fluorescence, and confocal microscopy.


RESULTS
Rhodopsin was detected at P5 and reached mature levels by P15; VEGF protein expression was transient, peaking at P10 to P15. In wild-type (wt) mice at P7, vessels had formed in the nerve fiber/retinal ganglion cell layer and showed a centroperipheral maturational gradient; some capillaries had formed a second bed on the vitread side of the inner nuclear layer (INL). By P28, the retinal vasculature had three mature capillary beds, the third abutting the sclerad aspect of the INL. In tr029VEGF mice, capillary bed formation was accelerated compared with that in wt, with abnormal vessels extending to the sclerad side of the INL by P7 and abnormally penetrating the photoreceptors by P28. Compared with P7, vascular lesions were more numerous at P28 when capillary dropout was also evident. At both stages, retinal layers were thinned most where abnormal vessel growth was greatest.


CONCLUSIONS
Concomitant damage to the vasculature and neural retina at early stages in tr029VEGF suggest that both tissues are affected, providing opportunities to examine early cellular events that lead to long-term disease.
van Eeden
Pauline E
PE
School of Animal Biology, The University of Western Australia, Crawley, Australia.
Tee
Lisa B G
LB
Lukehurst
Sherralee
S
Lai
Chooi-May
CM
Rakoczy
Elizabeth P
EP
Beazley
Lyn D
LD
Dunlop
Sarah A
SA
D000818:Animals; D002199:Capillary Permeability; D003930:Diabetic Retinopathy / Q000235:genetics / Q000473:pathology*; D004195:Disease Models, Animal; D005451:Fluorescein Angiography; D007124:Immunoenzyme Techniques; D051379:Mice; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009412:Nerve Fibers / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism; D012160:Retina / Q000196:embryology* / Q000254:growth & development; D012165:Retinal Ganglion Cells / Q000473:pathology*; D015861:Retinal Neovascularization / Q000235:genetics / Q000473:pathology*; D012171:Retinal Vessels / Q000473:pathology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012243:Rhodopsin / Q000235:genetics; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics*
D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D012243:Rhodopsin