The effect of retinoic acid on visual function and ocular tissues in guinea pigs with form-deprivation myopia

This study aimed to explore the potential mechanism of retinal retinoic acid (RA) in regulating form-deprivation myopia (FDM) in guinea pigs, and to analyze the effects of exogenous all-trans retinoic acid (atRA) and its inhibitor citral on the visual electrophysiology and RA content in ocular tissues of FDM guinea pigs. Two-week-old male albino guinea pigs were selected to construct the FDM model and divided into four groups: control group, FDM group, FDM + atRA group, and FDM + citral group. Myopia models were established by monocular deprivation with a hood, and corresponding drugs were administered by gavage for intervention. Axial length (AL) and refractive error (RE) were measured using an AB ultrasound instrument and an infrared refractometer for small animals, respectively. Flash visual evoked potential (F-VEP) was used to detect visual electrophysiological indicators. The RA content in the retina and retinal pigment epithelium-choroid-sclera complex was determined by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Statistical analysis was performed using SPSS 25.0 software. After 4 weeks of modeling, the right eye RE was − 2.05 ± 1.77 D and AL was 8.26 ± 0.10 mm in the FDM group. In the FDM + atRA group, the right eye RE was − 4.15 ± 1.65 D and AL was 8.42 ± 0.17 mm; both values differed significantly from those observed in the FDM group; F-VEP test showed that the amplitude of right eye in FDM + atRA group was 6.00 ± 3.91 μV, which was the lowest in the four groups, while the amplitude of right eye in FDM + citral group increased to 7.80 ± 4.71 μV. The retinal RA content of FDM group was 9.85 ± 1.49 ng/g, which was significantly higher than that of the blank control group (3.65 ± 0.55 ng/g); After the intervention of exogenous atRA, the retinal RA content in the FDM + atRA group decreased to 5.14 ± 0.69 ng/g, while the RA content in the RPE-choroid-sclera complex increased to 12.27 ± 0.35 ng/g, the highest in the four groups; Qualitative fundus photography showed no definitive or quantifiable structural differences among groups. No conclusions regarding vascular density or tissue thickness can be drawn from these subjective observations. Exogenous atRA can aggravate axial myopia and reduce the amplitude of F-VEP in FDM guinea pigs, and citral can partially reverse the above effects. Static differences in RA levels between the retina and RPE-choroid-sclera complex may correlate with myopia regulation, although this remains a speculative hypothesis that cannot confirm underlying dynamic molecular mechanisms.This study provides an experimental basis for the development of drug targets for myopia prevention and control.