Abstract
Greater degrees of human myopia are associated with thicker ciliary bodies, mandating the need to develop an appropriate animal model to study this relationship. Here, we determined if form deprivation-induced (FD) myopia impacts guinea pig ciliary body development.
Guinea pigs (n = 3) were monocularly FD for ~1 week. The ciliary body from responsive animals was dissected, RNA was isolated, and RNA-Seq was performed. Bioinformatics was used to compare treated and untreated eyes. A second group of guinea pigs were FD for ~1 week (n = 8). Eyes were collected, subjected to histological analysis, and morphologically evaluated.
RNA-Seq identified significant down-regulation of collagen alpha-1 (XII) chain (−2.30) and thrombospondin-1 (−2.30) transcripts in FD-treated compared to untreated eyes. Bioinformatics analysis revealed 470 genes that met a 1.5 fold differential gene expression threshold. Differentially regulated gene function (Ingenuity Pathway Analysis) was primarily related to (number of genes) cell morphology (169), cell movement (143), cellular development (161), cellular growth and proliferation (225), and cellular assembly and organization (152). Histological analysis found that FD eyes had shorter ciliary muscle (720.24 ± 98.92 μm vs. 753.61 ± 91.37 μm) and smaller cross-sectional areas (0.045 ± 0.01 mm2 vs. 0.052 ± 0.02 mm2) than untreated eyes.
Genetic and histological analyses found that ~1 week of visual FD may result in inhibited ciliary body growth. This growth pattern is in contrast to the growth response expected from human data and may indicate the FD-induced myopia may be different than human juvenile myopia.