Ultrastructure features of dhub lizard (Uromastyx aegyptia) cornea

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Abstract

Purpose

The Dhub lizard (Uromastyx egyptia) belongs to the family Agamidae and sub-family Uromasticinae, which is native of very dry and harsh desert climates. We report ultrastructural features of the dhub lizard cornea.

Methods

Four corneas of dhub lizards were fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate and magnesium chloride buffer. The tissue was washed in the buffer and dehydrated in a graded series of ethanol. The tissue was embedded in spur resin. The ultrathin sections were observed under a JEOL 1400 transmission electron microscope.

Results

The cornea of the dhub lizard is very thin (approximately 28μm) and consists of 4 layers: epithelium, stroma, Descemet’s membrane and endothelium. The sub-epithelial lamellae of the anterior stroma consisted of three or four collagen fibrils interlaced with each other. The lamellae in the anterior, middle and posterior were also thin and running parallel to each other. The epithelium constitutes approximately 14% of the cornea, whereas the stroma constitutes 80% of the cornea. The mean diameter of CF and PGs mean area in the anterior stroma were larger compared to the mean diameter and mean PGs area of the middle and posterior stroma.

Conclusion

The relatively thick epithelium of the cornea protects the stroma from drying out in the desert environment. The presence of large PGs suggests that they keep the hydration of the stroma at optimum level in the dry weather.

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