Abstract
Purpose::
The aim of this study was to investigate the expression of adiponectin and adiponectin receptors during laser induced CNV. Adiponectin (APN) is abundantly presents in serum and participates in regulation of cell proliferation, apoptosis and inhibits choroidal neovascularization (CNV).
Methods::
CNV was induced by laser photocoagulation in C57BL/6 mouse with Argon laser. Eyes were fixed in 4% paraformaldehyde (with L-lysine and Sodium Metaperiodate) by perfusion and then by immersion in 10% normal buffered formalin on day 1, 3, 5, and 7 post-laser. Paraffin 4 mkm sections were investigated by immunohistochemistry for APN, adiponectin receptors 1 (AdipoR1), adiponectin receptors 2 (AdipoR2), T-cadherin (TCad) and proliferating cell nuclear antigen (PCNA). Endothelial cells were detected with CD34 and Isolectin IB4. Three color immunostaining and colocalization analysis was performed.
Results::
Within the normal eye, APN was expressed in CD34 positive endothelial cells of some but not all choroidal vessels. AdipoR1, AdipoR2 and Tcad did not stain or stained weakly in the cytoplasm of CD34 positive cells. Additionally, intensive AdipoR2 and Tcad positive granular staining was discovered in nuclei of normal RPE and choroidal endothelial cells. After the laser injury a different pattern of expression for AdipoR1, AdipoR2 and Tcad was observed and the intensity of staining for AdipoR1, AdipoR2 and Tcad further increased at 24 h post-laser in Isolectin IB4 binding cells and peaked on day 7 post-laser. Intensive staining was also observed for adiponectin on day 7 post-laser however, the number of proliferating PCNA positive cells decreased at this time point.
Conclusions::
During development of CNV adiponectin produced in choroidal tissue by differentiated endothelial cells may inhibit proliferation of endothelial cells.
Keywords: choroid: neovascularization • proliferation • immunohistochemistry