Effect of vascular endothelial growth factor-A165 on scleral remodeling of guinea pigs with form-deprivation myopia

AIM: To investigate the effect of the intravitreal injection of vascular endothelial growth factor-A165(VEGF-A165)on the scleral remodeling of guinea pigs with form-deprivation myopia(FDM).METHODS: A total of 120 tricolor guinea pigs, aged three weeks, were randomly divided into 6 groups, with 20 in each group. The blank group did not undergo any intervention. In the FDM group, only the FDM model was established. In the phosphate buffer saline(PBS)group, 2.5 μL of PBS was injected into the vitreous cavity before establishing the FDM model. In the 1ng group, 5ng group, and 10ng group, VEGF-A165 was injected into the vitreous cavity at concentrations of 1, 5 and 10ng, respectively, before the establishment of the FDM model. The FDM model was established by covering the right eyes of guinea pigs with translucent balloons for 14d. The diopter and axial length of the right eyes were measured before and after covering. After 14d, the content of dopamine(DA)in retina was measured by high performance liquid chromatography. Additionally, the mRNA and protein expression levels of matrix metalloproteinase-2(MMP-2), tissue inhibitor of matrix metalloproteinase-2(TIMP-2), transforming growth factor(TGF)-β1, TGF-β2 and α-smooth muscle actin(α-SMA)in sclera were detected by reverse transcription polymerase chain reaction(RT-PCR)and Western blot.RESULTS: Before covering, there were no significant differences in the diopter and axial length of the right eyes of guinea pigs in all groups(P>0.05). After 14d of modeling, when compared with the blank group, FDM group showed an increase in the degree of myopia in the right eye, a prolongation of the axial length, a decrease in the content of DA in the retina, and an increase in the expression of MMP-2, TGF-β2 and α-SMA in the sclera. Conversely, the expression of TIMP-2 and TGF-β1 were decreased(P<0.01). However, in comparison to the FDM group, the degree of myopia in the 1ng, 5ng, and 10ng groups of guinea pigs decreased, the growth trend of axial length slowed, the content of DA in the retina increased, and the expression of MMP-2, TGF-β2 and α-SMA in the sclera decreased. Furthermore, the expression of TIMP-2 and TGF-β1 in the sclera increased(P<0.01). As the concentration of intravitreal injection of VEGF-A165 increased, the degree of myopia in the right eye of guinea pigs gradually increased, and the axial length gradually prolonged. The content of DA in the retina gradually decreased, the expression of MMP-2, TGF-β2, and α-SMA in the sclera gradually increased, while the expression of TIMP-2 and TGF-β1 decreased gradually.CONCLUSION: Intravitreal injection of VEGF-A165 can increase the content of DA in the retina of FDM guinea pigs, affect the expression of MMP-2, TIMP-2, TGF-β1, TGF-β2 and α-SMA in the sclera, and inhibit scleral remodeling of guinea pigs. Notably, the VEGF-A165 at the concentration of 1ng showed the most significant efficacy.