Nazıroğlu M, Çiğ B, Özgül C
Neuroscience Research Center, Süleyman Demirel University, Isparta, Turkey; Department of Biophysics, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey.
Department of Biophysics, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey.
Neuroscience. 2014 Mar 28;263:27-35. doi: 10.1016/j.neuroscience.2014.01.006. Epub 2014 Jan 13.
A main component of St. John's Wort (Hypericum perforatum, HP) is hyperforin which has antioxidant properties in dorsal root ganglion (DRG) neurons, due to its ability to modulate NADPH oxidase and protein kinase C. Recent reports indicate that oxidative stress through NADPH oxidase activates TRPM2 channels. HP may be a useful treatment for Ca(2+) entry and oxidative stress through modulation of TRPM2 channels in the DRG. We aimed to investigate the protective role of HP on Ca(2+) entry and oxidative stress through TRPM2 channels in DRG neurons of rats. The native rat DRG neurons were used in whole-cell patch-clamp, Fura-2 and antioxidant experiments. Appropriate, nontoxic concentrations and incubation times for HP were determined in the DRG neurons by assessing cell viability. The H2O2-induced TRPM2 currents were inhibited by 2-aminoethyl diphenylborinate (2-APB) and N-(p-amylcinnamoyl)anthranilic acid (ACA). TRPM2 current densities and cytosolic free Ca(2+) concentration in the neurons were also reduced by HP (2 and 24h). In Fura-2 experiments, cytosolic Ca(2+) mobilization was reduced by voltage-gated calcium channel blockers (verapamil+diltiazem, V+D) and HP. Glutathione peroxidase activity and GSH values in the DRG were high in HP, 2-APB and V+D groups although lipid peroxidation level was low in the groups. In conclusion, we observed a protective role for HP on Ca(2+) entry through a TRPM2 channel in the DRG neurons. Since over-production of oxidative stress and Ca(2+) entry are implicated in the pathophysiology of neuropathic pain and neuronal inflammation, our findings may be relevant to the etiology and treatment of neuropathology in DRG neurons.
圣约翰草（贯叶连翘，HP）的一种主要成分是金丝桃素，它在背根神经节（DRG）神经元中具有抗氧化特性，这归因于其调节NADPH氧化酶和蛋白激酶C的能力。最近的报告表明，通过NADPH氧化酶产生的氧化应激会激活TRPM2通道。HP可能是一种通过调节DRG中的TRPM2通道来治疗钙离子内流和氧化应激的有效药物。我们旨在研究HP对大鼠DRG神经元中通过TRPM2通道的钙离子内流和氧化应激的保护作用。在全细胞膜片钳、Fura-2和抗氧化实验中使用了原代大鼠DRG神经元。通过评估细胞活力，在DRG神经元中确定了HP的合适、无毒浓度和孵育时间。2-氨基乙基二苯基硼酸盐（2-APB）和N-（对戊基肉桂酰基）邻氨基苯甲酸（ACA）可抑制过氧化氢（H2O2）诱导的TRPM2电流。HP（2小时和24小时）也降低了神经元中的TRPM2电流密度和细胞溶质游离钙离子浓度。在Fura-2实验中，电压门控钙通道阻滞剂（维拉帕米+地尔硫卓，V+D）和HP降低了细胞溶质钙离子动员。在HP、2-APB和V+D组中，DRG中的谷胱甘肽过氧化物酶活性和谷胱甘肽（GSH）值较高，尽管这些组中的脂质过氧化水平较低。总之，我们观察到HP对DRG神经元中通过TRPM2通道的钙离子内流具有保护作用。由于氧化应激的过度产生和钙离子内流与神经性疼痛和神经元炎症的病理生理学有关，我们的发现可能与DRG神经元神经病理学的病因和治疗有关。
