Effect of vascular endothelial growth factor 165 on dopamine level in the retinas of guinea pigs with form-deprivation myopia

Background: Myopia is the most common refractive error because excessive increase in the axial length of a myopic eye leads to the thinning of the posterior scleral pole and can cause serious complications resulting in blindness. Thus, myopia has become a great concern worldwide. Dopamine (DA) plays a role in the development of myopia. Moreover, in Parkinson's disease, it has been proved that vascular endothelial growth factor 165 (VEGF165) can promote the survival and recovery of DA neurons, resulting in increased DA secretion in the striatum, thereby treating neuropathy. Therefore, we speculate that VEGF165 can also promote the release of DA in the retina to inhibit the occurrence and development of myopia. We aimed to investigate the effect of VEGF165 on DA levels in the retinas of guinea pigs with form-deprivation myopia (FDM) and the effects of DA on myopia prevention and control.

Methods: Healthy 3-week-old pigmented guinea pigs were randomly divided into blank, FDM, phosphate buffer saline (PBS), 1, 5, and 10 ng groups. The FDM model was established by covering the right eye continuously with a translucent latex balloon pullover for 14 days. The pigs in the PBS, 1, 5, and 10 ng groups were injected with PBS buffer and 1, 5, and 10 ng of VEGF165 recombinant human protein, respectively, in the vitreous of the right eye before masking. The refractive error and axial length were measured before and after modeling. All retinas were used for biomolecular analyses after 14 days.

Results: We found that the intravitreal injection of VEGF165 elevated DA levels in the retina and was effective in slowing the progression of myopia, and 1 ng of VEGF165 was the most effective. Moreover, the number of vascular endothelial cell nuclei in the 1 ng group was lower than that in the other VEGF165 groups.

Conclusions: Our data suggest that VEGF165 has a promoting effect on DA in the retinas of guinea pigs with FDM, potentially controlling the development of myopia.

Dopamine; Retina; VEGF; Vascular endothelial cells.