Exaggerated Eye Growth in IRBP-Deficient Mice in Early Development

Abstract

The size and weight of IRBP KO mouse eyes were greater than those of the WT mouse, even before eye-opening. Excessive ocular enlargement started between P7 and P10, with KO retinal arc lengths becoming greater compared with WT from P10 through P30 (18%; P < 0.01). The outer nuclear layer (ONL) of KO retinas became 20% thinner between P12 to P25, and progressed to 38% thinner at P30. At P30, there were 30% fewer cones per vertical section in KO than in WT retinas. Bromodeoxyuridine (BrdU) labeling indicated the same number of retinal cells were born in KO and WT mice. A spike in apoptosis was observed in KO outer nuclear layer at P25. These changes in size were accompanied by a large decrease in hyperopic refractive error, which reached -4.56 ± 0.70 diopters (D) versus +9.98 ± 0.993 D (mean ± SD) in WT, by postnatal day 60 (P60). CONCLUSIONS; In addition to its role in the visual cycle, IRBP is needed for normal eye development. How IRBP mediates ocular development is unknown.

Visually-Driven Ocular Growth in Mice Requires Functional Rod Photoreceptors

“…In mammals, this typically starts with hyperopic refractions and then shifts to emmetropia during early development to adolescence. 63,64 In WT mice used here and reported previously, 42,49,51,57,[65][66][67][68][69] the normal refractive development curve starts with hyperopic refractions, then shifts to greater levels of hyperopia (Fig. 1).…”

Violet Light Exposure Can Be a Preventive Strategy Against Myopia Progression

“…2a, b). The previously reported myopia-related genes (Ashby et al, 2014, Hawthorne and Young, 2013, Ma et al, 2014, Mathis et al, 2014, McGlinn et al, 2007, Ritchey et al, 2012, Wisard et al, 2011, Yoshikawa et al, 2014) such as Bmp2, Ednrb, Fgf2, Igf1, Il18, Irbp, Lumican, Sfrp1, Tgfb1, Vegfa, Vip, and Wnt2b were not found in the PC1 group in vivo , which indicates that they responded less to violet light. In the PC1 group, only one myopia protective gene (Pardue et al, 2013), EGR1 (ZENK, zif268), was found among the previously reported myopia related genes (Fig.…”

Interphotoreceptor Retinoid-Binding Protein Implications in Diabetic Retinopathy

“…In pathological conditions in which a deficiency of IRBP exists, an important anomaly of the photoreceptor cells and the visual cycle can be detected which leads in some cases to the development of retinitis pigmentosa, accumulation of the cytotoxic bis-retinoid A2E, cone-rod photoreceptor dystrophy and an elongated myopic eye shape [20][21][22][23][24][25].…”