Suppression of laser-induced choroidal neovascularization by intravitreal injection of tristetraprolin

AIM: To examine the effect of intravitreal adenoviral vector-mediated tristetraprolin (Ad-TTP) on VEGF mRNA expression in a rat model of laser -induced choroidal neovascularization. METHODS: Ad-TTP was prepared using a commercial kit. Retinal laser-induced photocoagulation (10 spots per eye) was performed on rats in this experimental choroidal neovascularization (CNV) model. Rats were divided into four groups: control (single intravitreal injection of balanced salt solution, n=10), laser-induced CNV (photocoagulation only, n=20), laser-induced CNV plus Ad-TTP injection (photocoagulation plus a single intravitreal Ad -TTP injection, n =20) and Ad -TTP injection only (n=10). Changes in choroidal morphology were evaluated in ten rats in the laser only and the laser plus Ad -TTP groups. Two weeks after laser injury, the size of CNV was calculated by perfusion with high -molecular -weight fluorescein isothiocyanate (FITC)-dextran. VEGF mRNA expression in retina-choroid tissue from ten rats in each group was measured by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Two weeks after treatment, the area of laser-induced CNV was reduced by approximately 60% in the rats given the Ad-TIP injection compared with that in the laser -only group. There was a tendency toward decreased VEGF mRNA expression in the Ad -TTP injection groups. CONCLUSION: A single intravitreal injection of Ad-TTP significantly suppressed CNV size in this experimental laser -induced CNV model. Ad -TIP injection also decreased VEGF mRNA expression compared with that in the laser -induced CNV group. The present study is meaningful as the first study to investigate the effect of tristetraprolin delivered via intravitreal injection.