Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
Acta Ophthalmol. 2012 Dec;90(8):e609-15. doi: 10.1111/j.1755-3768.2012.02502.x. Epub 2012 Sep 13.
Epigallocatechin-3-gallate (EGCG), the major polyphenol of green tea, has been suggested to reduce glutamate excitotoxicity. We therefore investigated the potentially protective effects of EGCG against N-methyl-d-aspartate (NMDA)-induced excitotoxicity in the retina.
Female Wistar rats (n = 171) were divided into a normal control group (n = 9); saline control group with intravitreal saline injections (n = 54); NMDA control group with an intravitreal NMDA injection and intraperitoneal saline injections (n = 54); and NMDA study group (n = 54) receiving an intravitreal NMDA injection plus intraperitoneal EGCG (25 mg/kg) injections. Starting at 2 days prior to the intravitreal NMDA injection, the intraperitoneal injections were performed daily for the whole study period. At 12 hr, 1, 2, 3 days, 1 and 2 weeks after the intravitreal NMDA injection, the animals were killed. We counted the neurons in the retinal ganglion cell layer (GCL) on histological sections, measured the thickness of Thy-1 immunoreactivity and assessed the expression of Thy-1 mRNA by real-time polymerase chain reaction.
At all time-points, GCL cell density, thickness of Thy-1 immunoreactivity and expression of Thy-1 mRNA were significantly (all p < 0.05) lower in the NMDA control group than in the NMDA study group, in which the parameters were significantly (all p < 0.05) lower than in the saline control group and the normal control group. In both groups with an intravitreal NMDA injection, GCL cell density, thickness of Thy-1 immunoreactivity and expression of Thy-1 mRNA decreased significantly with increasing follow-up time.
Intraperitoneal application of EGCG resulted in a significantly less marked NMDA-associated loss of retinal ganglion cells.
表没食子儿茶素没食子酸酯（EGCG）是绿茶中的主要多酚，已被证明可减轻谷氨酸兴奋性毒性。因此，我们研究了 EGCG 对视网膜中 N-甲基-D-天冬氨酸（NMDA）诱导的兴奋性毒性的潜在保护作用。
将雌性 Wistar 大鼠（n = 171）分为正常对照组（n = 9）；生理盐水对照组，玻璃体内注射生理盐水（n = 54）；NMDA 对照组，玻璃体内注射 NMDA 加腹腔注射生理盐水（n = 54）；NMDA 研究组（n = 54），玻璃体内注射 NMDA 加腹腔注射 EGCG（25 mg/kg）。从玻璃体内 NMDA 注射前 2 天开始，每天进行腹腔注射，整个研究期间。在玻璃体内 NMDA 注射后 12 小时、1 天、2 天、3 天、1 周和 2 周时，处死动物。我们在组织切片上计数视网膜神经节细胞层（GCL）中的神经元，测量 Thy-1 免疫反应的厚度，并通过实时聚合酶链反应评估 Thy-1 mRNA 的表达。
在所有时间点，NMDA 对照组的 GCL 细胞密度、Thy-1 免疫反应的厚度和 Thy-1 mRNA 的表达均明显低于 NMDA 研究组（均 p < 0.05），NMDA 研究组明显低于生理盐水对照组和正常对照组（均 p < 0.05）。在玻璃体内注射 NMDA 的两组中，GCL 细胞密度、Thy-1 免疫反应的厚度和 Thy-1 mRNA 的表达随着随访时间的增加而显著下降。
腹腔内应用 EGCG 可显著减轻 NMDA 相关的视网膜神经节细胞丢失。
