Changes of Melanopsin Expression in the Retina of Guinea Pig during Experimental Myopia and Recovery Period

Abstract

Purpose

To explore whether melanopsin is associated with the development of myopia.

Methods

Seventy-two guinea pigs (3 weeks older) were randomly assigned to 6 groups: the form-deprivation myopia (FDM) group (monocularly covering the right eye for 14 days, n = 15), the FDM recovery group (removing the eye mask for 3 days, n = 13), the lens-induced myopia (LIM) group (monocularly wearing a −4D lens for 3 days, n = 15), the LIM recovery group (removing the lens for 2 days, n = 13), and another 2 age-matched normal groups (n = 8 each). The diopter, the vitreous chamber depth (VCD), and the axial length (AXL) were measured to confirm the effect of the treatments. Immunofluorescence and western blotting methods were used to examine the expression of melanopsin in the retina.

Results

Immunofluorescent results showed that in the FDM group, the melanopsin intensity in the retina of experimental eyes significantly decreased compared to those of contralateral eyes, but no significant difference was observed during their recovery periods. Western blotting showed that the expression of melanopsin in the experimental eyes of the FDM group was lower than that of the contralateral eyes (fold: 1.00 versus 1.36). The expression of melanopsin in the experimental eyes increased 3 days after removing form deprivation, although a slight reduction in melanopsin expression compared to that of the contralateral eyes (fold: 1.41 versus 1.58). For the LIM group, immunofluorescent showed an obvious decreased intensity of melanopsin-labeled cells in the experimental eyes compared to the contralateral eyes. Western blotting showed that although melanopsin expression in the experimental eyes decreased compared to that of the contralateral eyes (fold: 1.00 versus 1.96), no differences were found between two eyes 2 days after lens removal (fold: 1.99 versus 2.00).

Conclusion

The decreased expression of melanopsin in the retina may potentially participate in the development of FDM and LIM.

Keywords:

• Melanopsin
• form-deprivation
• lens induction
• myopia
• recovery

Author’s contributions

Xu contributed to the conception, immunofluorescence experiments, and the western blotting experiments. Dong performed the FDM animal experiment and drafted the article. He contributed to the FDM animal experiment. Qin designed the experiments, analyzed data, and critically revised the manuscript. All authors read the manuscript and approved the final version to be published.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data available within the article materials.

Additional information

Funding

This research was supported by the Science and Technology Innovation Program of Hunan Province (Grant No. 2020SK50107), and Science Research Foundation of Shenzhen Aier Eye Hospital (Grant No. SZAE2020B04).