Comparative study on ocular anatomical features concerning the breed and age differences in rabbits

Abstract

In non-clinical studies for ophthalmic products, three breeds of rabbits have been frequently used; Japanese White (JW), New Zealand White (NZW) and Dutch-belted (DB) rabbits. There is limited information available for the differences of the ocular anatomical features across the breeds and aging currently. In this study, we compared the ocular anatomical features (the sizes of eyeball, lens and vitreous) among these breeds of rabbits at different age levels; the juvenile (6 weeks old), the young-adult (13-22 weeks old) and mature periods (80-96 weeks old).

As a result, all ocular anatomical parameters increased with age in all the three breeds. Comparing the parameters among breeds, the values were comparable between JW and NZW rabbits at each age level, while those in DB rabbits were generally lower than those in the other breeds. The breed-difference in ocular parameters was not caused merely by that in the body weights. As for the aging, the growth rate of the whole eyeball from the juvenile to young-adult period was higher than that from young-adult to matured period without breed-differences. The growth ratios of the lens-weight and -volume were higher than that of the other parameters.

The present study would provide essential information for ocular anatomical features concerning the breeds and ages in rabbits, and would enable us to plan the study and to evaluate the study results accurately by consideration of the eye size in the ophthalmic research using rabbits.