Expression of SCO1 and SCO2 after form-deprivation myopia in Guinea pigs

The retina is a highly energy-consuming tissue associated with visual development, and the reduced quality of retinal imaging can be related to myopia. Synthesis of cytochrome c oxidase 1 (SCO1) and synthesis of cytochrome c oxidase 2 (SCO2) are involved in ATP (adenosine triphosphate) synthesis and energy metabolism. This study aimed to observe the morphologic changes and investigate the expression of SCO1 and SCO2 induced by form-deprivation myopia (FDM) in the retina and sclera of guinea pigs.

Thirty-six 3-week-old male guinea pigs were randomly assigned to one of two groups: (1) the model group (n  =  18), in which the right eyes were covered by a thin opaque balloon as FDM group, and the left eyes were uncovered and served as the contralateral control group; (2) the blank control group (n  =  18), in which bilateral eye received no manipulation. Eyeballs were enucleated for histological analysis. The retina and sclera of the guinea pigs were separated to determine the protein and mRNA expression levels of SCO1 and SCO2, respectively.

After four weeks of form deprivation (FD), the refractive degree and axial length increased significantly (P < 0.001). The retinal and scleral tissues were moderately thinner, and the ganglion cells and the cells of inner and outer nuclear layers in the retina became fewer. Compared with the contralateral control group (P < 0.001) and the blank control group (P < 0.001), the collagen content of the sclera became less in the FDM group. The protein and mRNA expression levels of SCO1 and SCO2 in the FDM group were significantly lower than those in the contralateral control group and the blank control group (P < 0.05).

The morphologies of the retina and sclera were changed, and the expression of SCO1 and SCO2 at the protein and transcription levels was significantly reduced in the FDM group. Given these changes, SCO1 and SCO2 genes may be involved in myopic progression.