The developmental changes of ERGs on spontaneous retinal degeneration of Celestial goldfish

Abstract

The Celestial goldfish, which belongs to the family of telescope-eye goldfish, displays unique spontaneous retinal degeneration associated with developmental anterodorsal protrusion of the eyeball. We observed concurrent changes in the electroretinogram. At the age of 75 days, the retinal layer was developed fully and the electroretinogram exhibited b-wave dominance similar to that of adult common goldfish. At the age of 105 days, when the eyeball began to protrude laterally, the b-wave amplitude decreased to 52% of its earlier developmental stage, with a prolonged peak time. Histologic change was observed in the retinal pigment epithelium and photoreceptor layers. At the age of 135 days, when the eyeball protruded further anterodorsally, the histologic changes extended to all retinal layers and the ERG b-wave was extinguished. Electrophysiologic and histologic changes in the Celestial goldfish eye were found to be proportional to the grade of eye protrusion. Since similar goldfish do not show these changes, however, the Celestial goldfish may be a new model of hereditary retinal degeneration.

Study on Physiological and Biochemical Index of Blood and Vitreous Humor in the Celestial Goldfish (<em>Carassius auratus</em>)

“…Both celestial and telescope goldfish had suffered from visual function deficit, but the eye diseases were different between them. Celestial goldfish and goldfish with dragon's eyes both have abnormal functioning of the eyes, however, the development of celestial goldfish is accompanied by varying degrees of retinal degeneration [6], resulting in narrow vision and low light; Although the telescope goldfish 's eyeballs were protruding as well, its myopia was severe, and there was no retinal degeneration [49]. By comparative analysis, the albumin concentration in the vitreous humor of our celestial goldfish was higher than that of David's telescope goldfish [48], so it is speculated that probably celestial goldfish have a more severe degree of change in the condition of the membranes associated with the bloodretinal barrier than goldfish with dragon's eyes.…”

“…So far, few studies have been done on celestial goldfish, much of which has focused on their genetics and body color [3][4][5]. Some reports have also suggested that celestial goldfish have a degenerated retina and weak vision [6,7], making them suitable as model animals for the study of human eye diseases [8]. Blood is an crucial component of the fish organism and immune system [9], and blood indicators have historically been emphasized by production practitioners and theorists, and are frequently used to assess the health, nutrition, and environmental adaptation status of fish [10], as well as water quality monitoring [11].…”