Effect of human RAD50 gene therapy on glaucoma filtering surgery in rabbit eye

To investigate the antiproliferative effects of the subconjunctival injection of human RAD50 (hRAD50) on fibroblasts after glaucoma filtering surgery.

After glaucoma filtering surgery in normal rabbit eye, the subconjunctival injection of hRAD50 was performed. Morphologic changes in the subconjunctival area of hRAD50-treated eyes were compared with those of mitomycin C (MMC)-treated and control eyes using light and electron microscopy. Results. Two weeks after hRAD50 treatment (2 microg), the conjunctival epithelium increased in thickness and had many tonofilaments, but the basal lamina was intact. The subconjunctival fibroblasts exhibited a granular endoplasmic reticulum without distension. Most of the collagen bundles and fibers around the fibroblasts disappeared, and apoptotic cells with many fragmented nuclei and condensed chromatin were observed. Four weeks after hRAD50 treatment, the findings were similar with those of 2 weeks except for a slight increase in the number of collagen bundles and fibers and the appearance of macrophages. In MMC-treated eyes, the conjunctival epithelium also increased in thickness and had many tonofilaments. However, intercellular spaces were widened and the basal lamina was interrupted in some areas. Most of the collagen bundles and fibers were shortened, and apoptotic cells were also observed.

These results demonstrate that the histologic antiproliferative effects of local hRAD50 on the conjunctival fibroblasts are similar to those of MMC, but without damage to the basal lamina of the conjunctival epithelium, and suggest that hRAD50 may be useful as a possible antifibroblastic agent for glaucoma filtering surgery. However, further investigations are needed to test for possible systemic complications, which so far have not been reported.