Retinoic acid increases in the retina of the chick with form deprivation myopia.

We previously reported that expression of retinoic acid receptor beta increases in the sclera of the 2-week-old chick with form deprivation myopia (FDM) and that all-trans-retinoic acid (t-RA) influences proliferation and differentiation of scleral cells. The purpose of this study was to quantify t-RA in the retina of the chick with FDM and to investigate the role of t-RA in FDM in the chick. FDM was induced in 2-day-old chicks by placement of a translucent plastic goggle over one eye, with the contralateral eye used as a control. After 5 days, the chicks were sacrificed. t-RA was extracted from neural retina and served for high-performance liquid chromatography analysis. 3H-t-RA was used for normalization. Pieces of the retinae from 5 eyes served as one sample. As a result, t-RA was 09.60 +/- 0.86 ng/eye (0.387 +/- 0.056 ng/mg protein) in the myopic retina was significantly higher than that in the control (p < 0.05, n = 7). These results demonstrate that t-RA increases in the retina within 5 days after visual deprivation. This finding suggests that t-RA may play a role in the metabolic changes in FDM.