The cellular and molecular effects of RA and DEAB within the adult eye were next analyzed by using a TUNEL assay and qRT-PCR. After 2 days of treatment, exogenous RA did not significantly increase the percentage of apoptotic cells throughout the adult eye (4.8% ± 7.3%;
Fig. 7A) as compared to untreated (2.0% ± 2.4%,) and 0.1% DMSO control–treated (3.0% ± 3.5%) fish. However, localization of apoptotic cells showed that there was increased TUNEL staining in the IS and canalicular network in the ventral angle (
Fig. 7D2) and the RPE (
Fig. 7D3) as compared to untreated (
Figs. 7B1, 7B2, 7B3) and 0.1% DMSO control–treated fish (
Figs. 7C1, 7C2, 7C3). Treatment with RA did not affect cell survival in the dorsal iridocorneal angle (
Fig. 7D1). Treatment with 10 μM DEAB for 2 days significantly increased the percentage of apoptotic cells in the eye (9.3% ± 5.4%,
P < 0.001;
Fig. 7A), including in both iridocorneal angles (
Figs. 7E1, 7E2) and the retina (
Fig. 7E3). The RARβ-specific antagonist BMS195614 (1 μM) did not affect cell survival (4.1% ± 4.8%;
Fig. 7A) in the eye (
Figs. 7F1, 7F2, 7F3) after 2 days of treatment. The RARβ-specific antagonist LE135 (1 μM) did not significantly increase the percentage of apoptotic cells in the eye (5.2% ± 4.6%;
Figs. 7G1, 7G2, 7A), but did show apoptotsis in the photoreceptors and retinal pigment epithelium (
Fig. 7G3) after 2 days. Treatment with the RARβ-specific antagonist MM11253 (10 nM) for 2 days did not significantly change the percentage of apoptotic cells in the eye (4.6% ± 6.2%;
Figs. 7H1, 7A), but showed apoptosis in the retinal pigment epithelium (
Fig. 7H3) and the IS in the ventral angle (
Fig. 7H2). Quantitative RT-PCR demonstrated that treatment with 100 nM RA or 10 μM DEAB for 2 days did not significantly change the expression of the genes encoding RARα, RARβ, or RARγ (
Supplementary Fig. S2). Further, RA or DEAB did not affect
myoc or
pitx2a expression within the adult eye. Thus, RA has localized effects on ocular cell survival, which appear to be predominantly mediated by RARβ and RARγ, but after 2 days of treatment did not significantly alter overall expression of RARs or downstream targets within the eye.