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Updated: Oct 7, 2026
A Mouse Model for Laser-induced Choroidal Neovascularization
Published on: December 27, 2015
Colocalization of neuropilin-1 and Flk-1 in retinal neovascularization in a mouse model of retinopathy
H Ishihama1, M Ohbayashi, N Kurosawa
1Department of Biochemistry, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan. ishihama@tsuru.med.nagoya-u.ac.jp
Purpose:
To investigate the mechanisms of the development of retinal neovascularization, the localizations of vascular endothelial (VEGF) receptors Flk-1 and neuropilin (NP)-1 mRNAs were examined.
Methods:
The model of retinopathy of prematurity (ROP) was produced by ischemia-induced ocular neovascularization, by exposing postnatal day-7 mice to 75% oxygen for 5 days and then returning them to room air for 5 days. Retinal neovascularization was visualized by injection of fluorescein-dextran. Expression of Flk-1 and NP-1 mRNAs were examined by in situ hybridization with flatmount and serial sections of the retina. The localization of NP-1 was also confirmed by immunohistochemistry. Blood vessel patterns were characterized by immunohistochemical localization of von Willebrand factor (vWF).
Results:
Flatmount in situ hybridization showed intense expression of NP-1 and Flk-1 mRNAs colocalized in the area of neovascularization. In situ hybridization of serial sections of the retina revealed that expression of Flk-1 and NP-1 was restricted to neovascularized vessels of the retina from ROP mice.
Conclusions:
The restricted expression of Flk-1 and NP-1 on neovascularized vessels suggests that these molecules may play important roles in retinal neovascularization. This is the first report of the colocalization of NP-1 and Flk-1 on neovascularized vessels of the retina from ROP mice.
Insights
Vascular Endothelial Growth Factor (VEGF) receptors Flk-1 and Neuropilin-1 (NP-1) are co-expressed in neovascularized vessels in retinopathy of prematurity (ROP). This suggests their critical role in the development of abnormal blood vessel growth in the retina.
Area of Science:
- Ophthalmology
- Developmental Biology
- Molecular Biology
Background:
- Retinal neovascularization is a hallmark of several vision-threatening diseases.
- Understanding the molecular mechanisms driving aberrant blood vessel growth is crucial for developing effective therapies.
Purpose of the Study:
- To investigate the localization of vascular endothelial growth factor (VEGF) receptors Flk-1 and Neuropilin-1 (NP-1) mRNA in the context of retinal neovascularization.
- To elucidate the role of these receptors in the development of retinopathy of prematurity (ROP).
Main Methods:
- A mouse model of ROP was established by exposing P7 mice to high oxygen followed by room air.
- Retinal neovascularization was visualized using fluorescein-dextran injection.
- In situ hybridization and immunohistochemistry were employed to examine the expression and localization of Flk-1 and NP-1 mRNAs and proteins.
Main Results:
- Intense co-expression of Flk-1 and NP-1 mRNAs was observed in areas of neovascularization.
- Expression of both receptors was specifically restricted to the newly formed blood vessels in ROP retinas.
- Immunohistochemistry confirmed the localization of NP-1 on neovascularized vessels.
Conclusions:
- The restricted expression pattern of Flk-1 and NP-1 on neovascularized vessels indicates their significant involvement in retinal neovascularization.
- This study provides the first report of the co-localization of NP-1 and Flk-1 on neovascularized vessels in a mouse model of ROP.
