Retro-orbital injection of FITC-dextran is an effective and economical method for observing mouse retinal vessels.
OBJECTIVE
To assess the effects of retro-orbital (RO) injection of fluorescein isothiocyanate dextran (FITC-dextran) for observing mouse retinal vessels.


METHODS
Oxygen-induced retinopathy (OIR) was induced in 7-day postnatal (P7) C57BL/6J mice by exposing them to a 75% oxygen atmosphere for 5 days and then returning them to room air at P12. At P17, 45 P17 OIR mice and 12 normal mice received an RO injection of FITC-dextran. Five P17 OIR mice were perfused with FITC-dextran via the left ventricle. Retinal ﬂatmounts were viewed under a ﬂuorescence microscope and a confocal microscope. Following RO injection or left ventricular (LV) perfusion, the areas of neovascularization, as well as the total retina areas, were measured and analyzed using Image Pro-Plus 5.1 software.


RESULTS
The suitable volume of FITC-dextran for RO injection to observe the retinal vessels of a P17 OIR mouse was 0.05 ml, the 5% volume required to achieve similar results by administering FITC-dextran using LV perfusion. The total retinal vessels in P17 OIR mice could be fully observed under a ﬂuorescence microscope 3 s after RO injection of FITC-dextran. Our study showed that RO injection of FITC-dextran was suitable for observing the retinal vessels of all postnatal mice. There was no significant difference in evaluating retinal neovascularization between RO injection and LV perfusion of FITC-dextran (p>0.05).


CONCLUSIONS
Retro-orbital injection of FITC-dextran is an economical method for observing retinal vessels in mice, when compared with LV perfusion of FITC-dextran.
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
Shiqing
S
Li
Tao
T
Li
Yan
Y
Luo
Honghua
H
Yu
Yuying
Y
Sun
Huanjiao
H
Zhou
Xiaoling
X
Liang
Juan
J
Huang
Shibo
S
Tang
D000818:Animals; D000831:Animals, Newborn; D003911:Dextrans; D005451:Fluorescein Angiography / Q000379:methods*; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives*; D006352:Heart Ventricles; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007231:Infant, Newborn; D056965:Injections, Intraocular; D051379:Mice; D008810:Mice, Inbred C57BL; D057054:Molecular Imaging / Q000379:methods*; D010100:Oxygen; D010477:Perfusion; D012160:Retina / Q000187:drug effects / Q000473:pathology*; D012171:Retinal Vessels / Q000187:drug effects / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000209:etiology / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012984:Software
D003911:Dextrans; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate; D010100:Oxygen