Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Rome.
Invest Ophthalmol Vis Sci. 2011 Feb 22;52(2):1070-7. doi: 10.1167/iovs.10-5966.
Curcumin, a phenolic compound extracted from the rhizome of Curcuma longa, was found to attenuate NMDA-induced excitotoxicity in primary retinal cultures. This study was conducted to further characterize curcumin neuroprotective ability and analyze its effects on NMDA receptor (NMDAr).
NMDAr modifications were analyzed in primary retinal cell cultures using immunocytochemistry, whole-cell patch-clamp recording and western blot analysis. Cell death was evaluated with the TUNEL assay in primary retinal and hippocampal cultures. Optical fluorometric recordings with Fura 2-AM were used to monitor Ca(2+).
Curcumin dose- and time-dependently protected both retinal and hippocampal neurons against NMDA-induced cell death, confirming its anti-excitotoxic property. In primary retinal cultures, in line with the observed reduction of NMDA-induced Ca(2+) rise, whole-cell patch-clamp experiments showed that a higher percentage of retinal neurons responded to NMDA with low amplitude current after curcumin treatment. In parallel, curcumin induced an increase in NMDAr subunit type 2A (NR2A) level, with kinetics closely correlated to time-course of neuroprotection and decrease in Ca(2+). The relation between neuroprotection and NR2A level increase was also in line with the observation that curcumin neuroprotection required protein synthesis. Electrophysiology confirmed an increased activity of NR2A-containing NMDAr at the plasma membrane level.
These results confirm the neuroprotective activity of curcumin against NMDA toxicity, possibly related to an increased level of NR2A, and encourage further studies for a possible therapeutic use of curcumin based on neuromodulation of NMDArs.
姜黄素是从姜黄根茎中提取的一种酚类化合物，已被发现可减轻原代视网膜培养物中 NMDA 诱导的兴奋性毒性。本研究旨在进一步研究姜黄素的神经保护作用，并分析其对 NMDA 受体（NMDAr）的影响。
使用免疫细胞化学、全细胞膜片钳记录和 Western blot 分析在原代视网膜细胞培养物中分析 NMDAr 修饰。使用 TUNEL 测定法在原代视网膜和海马培养物中评估细胞死亡。使用 Fura 2-AM 的光学荧光记录监测 Ca(2+)。
姜黄素剂量和时间依赖性地保护视网膜和海马神经元免受 NMDA 诱导的细胞死亡，证实了其抗兴奋毒性作用。在原代视网膜培养物中，与观察到的 NMDA 诱导的 Ca(2+) 上升减少一致，全细胞膜片钳实验表明，在用姜黄素处理后，更高比例的视网膜神经元对 NMDA 产生低幅度电流反应。平行地，姜黄素诱导 NMDAr 亚基 2A（NR2A）水平增加，其动力学与神经保护的时间过程和 Ca(2+) 的减少密切相关。神经保护和 NR2A 水平增加之间的关系也与观察到的姜黄素神经保护需要蛋白质合成一致。电生理学证实了在质膜水平上 NR2A 含量增加的 NMDAr 活性增加。
这些结果证实了姜黄素对 NMDA 毒性的神经保护活性，可能与 NR2A 水平增加有关，并鼓励进一步研究基于 NMDAr 神经调节的姜黄素的可能治疗用途。
