[The effect of Sairei-to on oxygen-induced retinal neovascularization in the neonatal rat].

ABSTRACT

PURPOSE: To study the effect of Sairei-to (ST), a Japanese traditional medicine, on oxygen-induced retinopathy (OIR) in rats. METHODS: OIR was induced by maintaining Sprague-Dawley neonatal rats in 80% oxygen for 12 days. The rats were treated once daily with oral administration of 0.75 g/kg (n = 9), 1.5 g/kg (n = 13) of ST in water, or water alone (WA, n = 13) at 5 mL/ kg body weight from day 6 to day 17. On day 18, retinal samples were collected. Retinal neovascularization (NV) was assessed by the NV score, and by the percentage of avascular area (% AVA), using a method previously reported. The number of severe retinal NV cases (NV > or = 9) was compared. The retinal vascular endothelial growth factor (VEGF) concentrations were measured with an immunoassay kit, at 0, 12, 24, 72 and 144 hours after oxygenation. RESULTS: NV score and % AVA decreased in the ST treated group compared to the WA group. However, severe NV was seen in five cases of WA and in one case of the ST treated group. Thus severe NV was inhibited significantly by ST treatment (p = 0.0185). Retinal VEGF did not differ between groups at any time points. CONCLUSION: These data suggest that severe NV in OIR is inhibited by ST treatment.