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Distribution and isoform characterization of type XII collagen in bovine cornea

T Kato1, K Nakayasu, A Kanai

  • 1Department of Ophthalmology, Juntendo University, Tokyo, Japan. tak-kato@tkg.att.ne.jp

Ophthalmic Research
|September 6, 2000
PubMed

Insights

Type XII collagen is found in the corneal stroma, particularly the superficial layers, and along collagen fibrils. Its distribution may influence corneal transparency.

Area of Science:

  • Biochemistry
  • Ophthalmology
  • Connective Tissue Research

Background:

  • Type XII collagen is a fibril-associated collagen with interrupted triple helices (FACIT).
  • Its role in corneal structure and transparency is not fully understood.

Purpose of the Study:

  • To determine the precise localization of type XII collagen in bovine corneas.
  • To investigate the isoforms of type XII collagen present in bovine cornea and skin.

Main Methods:

  • Streptavidin peroxidase immunohistochemistry and immunoelectron microscopy for localization.
  • Western blotting to analyze collagen isoforms in tissue extracts.

Main Results:

  • Type XII collagen was exclusively found in the corneal stroma, absent in epithelium, Descemet's membrane, and endothelium.
  • It was distributed throughout the stroma, with prominent localization in the superficial stroma.
  • Immunoelectron microscopy revealed type XII collagen along banded collagen fibrils with periodic distribution.
  • Bovine cornea extracts contained both long and short isoforms of type XII collagen, while skin extracts had only the short isoform.

Conclusions:

  • Type XII collagen is a stromal component of the bovine cornea.
  • The distribution and presence of specific isoforms of type XII collagen may contribute to the regular arrangement of collagen fibrils, maintaining corneal transparency.

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