Abstract
Purpose:
Proteoglycans (PG) are compounds of extracellular matrix (ECM) or membrane cellular involved in severals activities during retinal development. Chondroitin sulfate neurocan and phosphacan are major nervous-tissue PGs and are upregulated at early development, mediating neurite and axonal growth, cell differentiation and migration. Otherwise, heparan sulfate PG syndecan-3 binds to vascular endothelial growth factor (VEGF) stimulating axonal elongation. VEGF is a glycoprotein synthetised from cells that plays essential part of physiological angiogenesis, neovascularization deseases and neuroprotection. Bevacizumab (BVZ), an anti-VEGF agent, has been used to treat severals vasoproliferative disorders in adult eyes and currently it has been applied in patients with retinopathy of Prematurity. The purpose of this research is to investigate the effects of BVZ on ECM and membrane cellular PGs involved in cellular differentiation and axonal alongation in a newborn rat retina explant model.
Methods:
Retinal explants of sixty 2-day-old Lister hooded rats were obtained after eye enucleation and maintained in culture media with or without BVZ for 48 hours. Immunohistochemical staining was assessed against neurocan, phosphacan and syndecan-3 PG and protein content was quantified based on the intensity of labeling under confocal microscope. Gene expressions for such PG were quantified by real-time reverse-transcription polymerase chain. The amount of neurocan, phosphacan and syndenca-3 mRNAs were calculated relative to the amount of ribosomal protein ARBP as reference gene. Results obtained from treatment and control groups were compared using Mann-Whitney U test, assuming statistical relevance P<0.05.
Results:
No significant difference in labeling or mRNA content for phosphacan and syndecan-3 was observed between groups. However, neurocan intensity of labeling was significantly decreased in BVZ-treated retinas (0.16 ± 0.46) compared with controls (1.41 ± 1.74; P= 0.028). Neurocan mRNA content was also decreased in BVZ-treated group (0.54 ± 0.20) compared with controls (1.165 ± 0.28; P= 0.014).
Conclusions:
Bevacizumab interferes with the early maturation of retinal glial cells in 2-day-old Lister hooded rat explants by modulating extracellular matrix proteoglycan neurocan involved in axonal development and cell differentiation. Thus, it should be carefully used on newborn treatment.
Keywords: 700 retinal neovascularization •
519 extracellular matrix •
698 retinal development