Abstract: Objective To study the effect of intravitreal injection of vascular endothelial growth factor-B(VEGF-B)on the level of dopamine(DA)in the retina of form-deprivation myopia(FDM)guinea pigs. Methods A Total of 147 healthy 3-week-old guinea pigs, male or female, were selected and randomly divided into 7 groups, with 21 guinea pigs in each group. The eyes of guinea pins in the blank group were not intervened,and the right eyes of the guinea pins in other 6 groups were covered with translucent latex balloon for 14 days to establish the FDM model. After preparation, 2.5 μL of PBS buffer and VEGF-B at concentrations of 0.25 ng, 2.5 ng, 5 ng and 50 ng were intravitreally injected into the right eye of the guinee pigs in the PBS group as well as the groups of 0.25 ng, 2.5 ng, 25 ng and 50 ng. Ocular refraction and axial length were recorded in both eyes of each animal before and after modeling. After 14 days, immunofluorescence was used to detect the number of tyrosine hydroxylase positive cells; Western blotting was used to detect the expression of TH protein in the retina; HE staining was used to observe the number of retinal vascular endothelial cell nuclei; and high performance liquid chromatography was used to determine DA and 3,4-dihydroxyphenylacetic acid(DOPAC)content and DA metabolic rate. Results Before modeling,there was no significant difference in the diopter and axial length of the right eye among the 7 groups(P>0.05). After modeling, compared with the blank group, refractive error was shifted to the myopic side in the FDM and PBS groups, the axes of the eyes grew, and the TH, DA, and DOPAC levels were reduced(P<0.05). Compared to the FDM group, the guinea pigs in the VEGF-B groups(0.25 ng, 2.5 ng, 25 ng and 50 ng)exhibited a decrease in myopia progression and inhibition of axial elongation, accompanied by increased expression levels of TH, DA, and DOPAC(all P<0.05). As the concentration of VEGF-B increased, there was a gradual enhancement in the suppression of axial growth and reduction in myopia severity while observing a progressive elevation in TH expression and other indicators. There was no significant difference in the metabolic rate of DA and the number of retinal vascular endothelial cell nuclei among the 7 groups(P>0.05). Conclusion The intravitreal injection of VEGF-B can enhance retinal DA levels and inhibit axial elongation, thereby effectively suppressing myopia development in FDM guinea pigs without inducing neovascularization. Notably, the impact of VEGF-B on DA was particularly pronounced in the 50 ng group.

Key words: Vascular endothelial growth factor-B, Form deprivation myopia, Dopamine, Retina, Tyrosine hydroxylase