Megalophthalmia in Black Moor goldfish: an experimental model to study metabolic events associated with eye expansion

Abstract

Aim: To compare the biochemical contents in the vitreous of Black Moor and common goldfish in order to explore some of the biochemical changes associated with the unlimited eye expansion in Black Moor goldfish.

Materials and methods: Vitreous humor was analyzed for small molecules and macromolecules. To separate small molecules, a Delta PAK C column was eluted by acetonitrile-trifluoroacetic acid-water, 2:0.01:97.99. To separate peptides, a Delta PAK C column was eluted by increasing acetonitrile concentration from 20% to 80%. The eluant was monitored by a photo diode array detector and platform LCZ mass detector. The chemical structure of compound 204 was investigated by mass spectrometry and nuclear magnetic resonance spectroscopy.

Results: Three remarkable biochemical properties were observed in the vitreous of Black Moor goldfish, includ- ing a marked elevation of lactic acid, the occurrence of compound 204, a dicarboxylic carbohydrate with a 6-member lactone ring structure, and a high concentration of peptides 13.67K and 27.34K.

Conclusion: A comparison of the biochemical contents of the vitreous between Black Moor and common gold- fish revealed specific metabolic changes associated with eye growth. The high lactic acid content indicates the activation of glycolysis when the normal restriction of eye growth after birth is lost. The occurrence of com- pound 204 reveals a new metabolic pathway of glucose metabolism in fishes not seen in mammalian tissues. The high amount of peptides 13.67K and 27.34K indicates a marked change in the biosynthetic activity for peptides in the vitreous cavity of growing eyes. The present data demonstrate the value of Black Moor goldfish as a model to study many biochemical events associated with eye growth.