Rasgrf1 mRNA expression in myopic eyes of guinea pigs

Genome-wide association studies of patients have linked the Rasgrf1 gene with myopia. The aim of this study was to investigate the messenger RNA (mRNA) expression of Rasgrf1 in the eyes of guinea pigs with induced myopia.

The myopia was induced by form deprivation in 24 guinea pigs, while additional 12 animals served as a control. Biometric measurements were used to monitor myopic progression. The animals were sacrificed at two, three and four weeks after beginning of the monocular form deprivation, followed by dissection of the retina, and the sclera, as well as mRNA isolation from both layers. A quantitative reverse transcriptase-polymerase chain reaction was performed to detect the expression of Rasgrf1.

The spherical equivalent in eyes subjected to form deprivation differed from the fellow eyes, with measurements of -3.80 ± 0.08 D, -3.96 ± 0.94 D and -4.00 ± 0.94 D at the two-, three- and four-week times, respectively, significantly more myopia than the inter-ocular difference in the control group (p < 0.05). The form-deprived eyes also had a longer axial length compared with the fellow eye: 1.37 ± 0.76 mm, 1.32 ± 0.65 mm and 0.92 ± 0.80 mm at two, three and four weeks, respectively, significantly different from the control group (p < 0.05). In contrast, there was no difference in the corneal curvature, anterior chamber depth or lens thickness between the two eyes at any time (p > 0.05). The increase of Rasgrf1 expression was observed in the sclera, with a fold change of 6.596, 4.379 after three weeks and 6.788, 5.711 after four weeks of treatment, compared with the fellow eyes and the control group, respectively (p < 0.05).

Rasgrf1 up-regulation was found in the sclera of myopic eyes; however, further investigation is needed to determine whether Rasgrf1 plays a causative role or is a consequence of myopia-induced scleral remodelling.