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Y. Saito, T. Ueda, T. Nakanishi-Ueda, Y. Hasebe-Takenaka, S. Tomoyasu, U. Dier, H. Yasuhara, S. A. Mousa, D. Armstrong, R. Koide; Effects of L-Theanine on Oxygen-Induced Retinal Neovascularization in the Neonatal Rat Model. Invest. Ophthalmol. Vis. Sci. 2008;49(13):2636. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
L-theanine [2-Amino-4-(ethylcarbamoyl) butyric acid] is a unique free form of amino acid found only in the tea plant and in the mushrooms Xerocomus badius and certain species of genus Camellia, C. japonica and C. sasanqua. The present study investigated the preventive effects of L-theanine in rat model of oxygen-induced retinopathy (OIR).
Neonatal Sprague-Dawley rats (P7) were exposed to daily cycles of 80% oxygen (20.5 h), ambient air (0.5 h), and progressive return to 80% oxygen (3 h) until postnatal day 12 (P12), then the rats were placed in ambient air until P18. The rats were treated once daily from P6 to P17 by gastric gavage of L-theanine (5 and 50 mg/kg) or distilled water (DW) at 50 uL/10 g body weight. On P12, P13, P14 and P18, the rats were sacrificed and the retinal samples were collected. At P18, the retinal neovascularization (NV) was scored and avascular areas (AVAs) were measured as a % of total retinal area (%AVAs) in ADPase stained retinas. VEGF-A, VEGFR-1, VEGFR-2, HIF-1, MMP-9 and IGF-1 were determined by RT-PCR analyses at each time point.
The NV scores in 5 mg/kg theanine (4.2 ± 0.5, n=16) and 50 mg/kg theanine (3.4 ± 0.6, n=14, P<0.05) were lower than those in DW (4.7 ± 0.6, n=16). The %AVAs in 5 mg/kg theanine (13.2 ± 2.8%, n=16) and 50 mg/kg theanine (9.4 ± 2.2%, n=14, P<0.01) were lower than those in DW (18.9 ± 2.9%, n=16). Theanine treatment reduced VEGF-A, VEGFR-1, IGF-1 and MMP-9 mRNA levels compared to DW treatment. VEGFR-2 and HIF-1 m RNA were not changed by theanine treatment.
There results indicate that L-theanine treatment might suppress the neovascularization via multiple signaling pathways in rat model of OIR. These data suggest the potential utility of L-theanine for prophylactic measures in ocular disorders associated with retinal neovascularization.
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