Purpose: To evaluate the feasibility of introducing exogenous tissue inhibitor of metalloproteinases-3 gene into the rat retinal pigment epithelium using hemagglutinating virus of Japan liposomes and to assess the effect of tissue inhibitor of metalloproteinases-3 overexpression in retinal pigment epithelium cells on the formation of experimental choroidal neovascularization.
Methods: Hemagglutinating virus of Japan liposomes containing hemagglutin epitope-tagged tissue inhibitor of metalloproteinases-3 gene were injected into the subretinal space in rat eyes. Localization of oligonucleotides was evaluated by fluorescence microscopy. Exogenous tissue inhibitor of metalloproteinases-3 mRNA expression was assessed by reverse transcribed polymerase chain reaction. Exogenous tissue inhibitor of metalloproteinases-3 protein expression was visualized by immunostaining with monoclonal antibody 12CA5 against the hemagglutin epitope. Three days after transfection of tissue inhibitor of metalloproteinases-3 gene into retinal pigment epithelium cells, intense laser photocoagulation was performed and the incidence of choroidal neovascularization was assessed by fluorescein fundus angiography.
Results: Exogenous tissue inhibitor of metalloproteinases-3 mRNA expression in the choroid and retina was detected on day 3. The efficiency of tissue inhibitor of metalloproteinases-3 gene transfection into retinal pigment epithelium cells was greatest on day 7 and decreased gradually thereafter. The incidence of choroidal neovascularization in tissue inhibitor of metalloproteinases-3 gene-transfected eyes was markedly decreased compared with controls.
Conclusions: This study shows that tissue inhibitor of metalloproteinases-3 gene can be transferred into rat retinal pigment epithelium using the hemagglutinating virus of Japan-liposome method and that tissue inhibitor of metalloproteinases-3 gene overexpression can inhibit development of experimental choroidal neovascularization. This method may represent a future treatment modality for human macular degeneration associated with choroidal neovascularization.