三七皂苷R_1通过雌激素受体调节ATF6/Akt信号通路减轻OGD/R所导致的神经元损伤

Protective effect of notoginsenoside R_1 on neuron injury induced by OGD/R through ATF6/Akt signaling pathway

三七皂苷R_1(notoginsenoside R_1,NGR_1)是传统中药三七的重要活性成分,也是雌激素受体激动剂。因其蕴含抗炎、抗氧化、抗凋亡等多种功能,故在疾病治疗中被普遍运用。为阐明NGR_1在缺血缺氧性脑病(hypoxic-ischemic brain damage,HIBD)中的潜在神经保护作用机制,该研究采用原代皮层神经元建立氧糖剥夺再灌注(oxygen-glucose deprivation/reoxygenation,OGD/R)损伤模型,并且给予NGR_1及雌激素受体阻断剂ICI-182780处理,然后分别采用MTT,LDH和Hochest 33342染色检测神经元存活率、细胞膜完整性和凋亡,Western blot检测抗凋亡通路ATF6α,p-Akt,Akt蛋白及凋亡相关蛋白Bax,Cleaved Caspase-3的表达。结果显示:神经元在OGD/R损伤后,其细胞存活率明显下降(P<0.05)、细胞膜相对完整性显著降低(P<0.05)、细胞凋亡加重(P<0.05),ATF6α,p-Akt表达下调且促凋亡蛋白Bax,Cleaved Caspase-3表达增加(P<0.05)。NGR_1处理后能够减轻OGD/R造成的神经元细胞损伤,上调ATF6α表达、促进Akt磷酸化并且减少Bax,Cleaved Caspase-3蛋白的表达(P<0.05),但是,NGR_1的这些神经保护性作用能够被雌激素受体阻断剂ICI-182780阻断。研究结果证实:NGR_1在缺血缺氧情况下对神经元具有保护性作用,该保护作用可能是NGR_1通过雌激素受体调控ATF6/Akt信号通路实现的。

Notoginsenoside R1 （ NGRt ）, a critical compound in traditional herb Panax notoginseng, is a kind of estrogen receptor agonist. It is reported to exhibit anti-apoptotic, anti-oxidative and anti-inflammatory properties activity, so it is widely used for treatment of various diseases. In order to investigate the potential neuroprotective effect of NGR1 in hypoxic-ischemic brain damage（HIBD） , primary cortical neurons were used in this study to establish oxygen-glucose deprivation/reoxygenation（OGD/R） injury models. They were treated with NGR1 and estrogen receptor inhibitor ICI-182780 respectively, then the neuronal survival, cell membrane integrity and apoptosis were assessed by MqT assay, lactate dehydrogenase test（LDH） and Hoechst 33342 stain respectively, while the protein expression levels of ATF6a,p-Akt,Akt,Bax and Cleaved Caspase-3 were measured by Western blotting. Results indicated that as compared with the blank control group, OGD/R could induce cell injury and apoptosis （ P 〈 0. 05 ）, reduce relative integrity of cell membrane （P 〈 0. 05 ）, decrease protein expression of ATF6a, p-Akt（ P 〈 0. 05 ）, and increase protein expression of Bax and Cleaved Caspase-3 （P 〈 0. 05 ） in the primary cortical cells. After NGR1 treatment, the expression levels of ATF6a, p-Akt were obviously increased, and the expression levels of Bax and Cleaved Caspase-3 and the apoptosis of neuron were decreased（P 〈 O. 05 ）. However, these neuroprotective properties of NGR1 against ODG/R-induced cell damage could be blocked by ICI-182780. This finding indicated that NGRt may protect the primary cortical neurons against OGD/R induced injury, and the mechanism may be associated with accelerating the activation of the ATF6/Akt signaling pathway via estrogen receptors.