Development of laser-induced choroidal neovascularization in rats after retinal damage by sodium iodate injection.

PURPOSE

To determine the role of the retinal pigment epithelium (RPE) in the development of laser-induced choroidal neovascularization (CNV) by selective damage with sodium iodate (SI).

METHODS

In group 1, diode laser photocoagulation was applied to the right eye of Long-Evans rats (n = 11). In group 2 (n = 11), SI was administered intravenously at a dose of 40 mg/kg of body weight 2 days after photocoagulation. In group 3 (n = 10), SI was injected 2 days before laser was applied. In group 4 (n = 10), SI was injected immediately after photocoagulation.

RESULTS

CNV ingrowth developed in 42 of 93 burns (45%) of the laser group and in 46 of 75 burns (61%) when SI was administered 2 days after laser (p = 0.036). No CNV developed in the other groups.

CONCLUSIONS

The angiogenic effect of the RPE is essential during the first hours after the onset of the laser-induced CNV process. When the RPE was damaged before or at the time of photocoagulation, CNV was not induced. These results suggest that RPE integrity is a decisive element in CNV formation.