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Ultrastructure features of camel cornea – collagen fibril and proteoglycans

Authors

  • Turki Almubrad,

    1. Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, PO Box 10219, Riyadh 11433, Saudi Arabia
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  • Saeed Akhtar

    1. Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, PO Box 10219, Riyadh 11433, Saudi Arabia
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  • The work has been presented as a poster in (European Association for Vision and Eye Research) EVER, Greece in October 2010.

Address communications to:
Dr. S. Akhtar
Tel.: 00966 4693532
Fax: 00966 4350810
e-mail: akhtars@ksu.edu.sa; saeed48@hotmail.co.uk

Abstract

Introduction  The uniform distribution of collagen fibrils and proteoglycans maintain the transparency of normal cornea. We describe the ultrastructural features of camel cornea including collagen fibrils and proteoglycans (PGs).

Methods  Camel corneas (of 6-, 8-, and 10-month-old animals) were fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate buffer and processed for electron microscopy. The ‘AnalySIS LS Professional’ program was used to analyze the collagen fibril diameter.

Results  The camel cornea consists of four layers: the epithelium (227 μm), stroma (388 μm), Descemet’s membrane (DM), and endothelium. The epithelium constituted 36% of the camel cornea, whereas corneal stroma constituted 62% of the corneal thickness (629 μm). The PGs in the posterior stroma were significantly larger in number and size compared with the anterior and middle stroma. The collagen fibril diameter was 25 nm and interfibrillar spacing 40 nm. Fibrillar structures are present throughout the DM.

Conclusion  The structure of the camel cornea is very different from human and other animals. The unique structure of the cornea might be an adaptation to help the camel to survive in a hot and dry climate. The camel cornea may also be a good model to study the effect of hot and dry climates on the cornea.

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