Abstract
Purpose::
To establish a rabbit CNV-model based on subretinal injection of RPE cells and/or microbeads and to analyze the involvement of inflammatory cells and the expression of cytokines and growth factors over time.
Methods::
Dutch-belted rabbits (2-3 lb) received a subretinal injection (30 µl) of either a combination of homologous RPE cells (2x105/µl) and microbeads (2x105/µl) both or only microbeads in the right eye. Five rabbits received subretinal injection of PBS and served as control. The CNV growth pattern and the expression of growth factors and cytokines were documented over a period of 21 days by light microscopy and immunohistochemistry. The thickness of the CNV-complex (T) was measured from the outer border of the retinal pigment epithelium or Bruch’s membrane up to the inner surface of the CNV, and the size of the CNV between retinal pigment epithelium monolayers adjacent to the lesion (L) was measured. The greatest T and L values in 10 serial sections from each membrane were recorded and averaged (mean ±SD).
Results::
All membranes demonstrated a type 2 (subretinal) growth pattern. A continuous increase of the CNV thickness was observed in all study groups up to day 10, followed by a gradual decrease between days 14 and 21. The CNV size was larger in the RPE/microbead group (TRPE/beads x LRPE/beads = 1900.0 x 77.2 µm) compared to the microbead groups (Tbeads x Lbeads = 550 x 38.7 µm). There was no membrane in PBS injected control group. Inflammatory cells and various growth factors/cytokines (TGF-ß, MCP, VEGF, PEDF, TF) were identified.
Conclusions::
Our model using the rabbits is appropriate to initiate CNV growth (type 2) by subretinal injection of RPE and/or microbeads and to evaluate the different stages of CNV formation (initiation, inflammatory active, inflammatory inactive). It provides additional information regarding the inflammatory cells, cytokines and growth factors associated with CNV growth.
Keywords: age-related macular degeneration • choroid: neovascularization • neovascularization