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Updated: Aug 4, 2026
The Corneal Micropocket Assay: A Model of Angiogenesis in the Mouse Eye
Published on: August 16, 2014
Expression and localization of angiogenic inhibitory factor, chondromodulin-I, in adult rat eye
H Funaki1, S Sawaguchi, K Yaoeda
1Department of Structural Pathology, Institute of Nephrology, Niigata University, 1-757 Asahimachi-dori, Niigata 951-8510, Japan.
Purpose:
To determine the role in the eye of chondromodulin (ChM)-I, which has been identified in cartilage as an angiogenic inhibitor, the expression and localization and a possible function of ChM-I were investigated.
Methods:
Expression and localization of ChM-I in rat eyes were examined by RNase protection assay and in situ hybridization and by immunostaining, using an antibody against a synthetic peptide. The effect of recombinant ChM-I on tube morphogenesis of retinal endothelial cells was examined in culture.
Results:
The rat ChM-I gene was determined to encode the open reading frame of 334 amino acid residues, and ChM-I mRNA was exclusively expressed in cartilage, eye, and cerebellum in rats. ChM-I mRNA expression was evident in the iris-ciliary body, retina, and scleral compartments, but not in other compartments of the eye. In situ hybridization revealed mRNA expression in the ganglion cells, inner nuclear layer cells, and pigment epithelium in the retina and in the nonpigment epithelium of the ciliary body. Immunoreactive ChM-I was present in these cells and also in the vitreous body. Western blot analysis detected an approximately 25-kDa band of ChM-I presumed as a secretory form in the aqueous humor and vitreous body and an approximately 37-kDa band as a precursor form in the retina. Recombinant human ChM-I inhibited tube morphogenesis of human retinal endothelial cells in vitro.
Conclusions:
These observations indicate a potential role for ChM-I in inhibition of angiogenesis in the rat eye.
Insights
Chondromodulin (ChM)-I, an angiogenic inhibitor found in cartilage, is expressed in the rat eye. This suggests ChM-I may play a role in inhibiting eye angiogenesis.
Area of Science:
- Ophthalmology
- Molecular Biology
- Biochemistry
Background:
- Chondromodulin (ChM)-I is known to inhibit angiogenesis in cartilage.
- Its role in ocular tissues is not well understood.
Purpose of the Study:
- To investigate the expression, localization, and function of ChM-I in the rat eye.
- To determine if ChM-I acts as an angiogenic inhibitor within the eye.
Main Methods:
- RNase protection assay and in situ hybridization were used to examine ChM-I mRNA expression and localization in rat eyes.
- Immunostaining identified ChM-I protein localization.
- Recombinant ChM-I's effect on retinal endothelial cell tube morphogenesis was assessed in vitro.
Main Results:
- ChM-I mRNA was exclusively expressed in cartilage, eye, and cerebellum, with specific localization in the iris-ciliary body, retina, and sclera.
- Immunoreactive ChM-I was detected in retinal ganglion cells, inner nuclear layer, pigment epithelium, and ciliary body.
- A secretory form of ChM-I was found in aqueous humor and vitreous body.
- Recombinant ChM-I inhibited retinal endothelial cell tube formation in vitro.
Conclusions:
- Chondromodulin (ChM)-I is expressed in various compartments of the rat eye.
- These findings suggest a potential role for ChM-I in inhibiting ocular angiogenesis.
