玄参环烯醚萜苷对氧糖剥夺再灌注细胞模型内质网钙稳态的调控作用

目的: 阐明玄参环烯醚萜苷（IGRS）基于调控内质网应激反应对抗脑缺血再灌注损伤的作用及机制。方法: 采用IGRS（50、100、200 μg/mL）预处理PC12细胞24 h，然后构建氧糖剥夺/再灌注（OGD/R）细胞模型。MTT法检测细胞存活率，细胞内乳酸脱氢酶（LDH）释放法检测细胞损伤程度；流式细胞术检测细胞凋亡率，蛋白质印迹法检测B细胞淋巴瘤-2（Bcl-2）、Bcl-2相关X蛋白（Bax）、C/EBP同源蛋白（CHOP）、半胱氨酸天冬氨酸蛋白酶12（caspase-12）、葡萄糖调节蛋白78（GRP78）水平；实时逆转录PCR法检测肌浆网钙泵2（SERCA2）、1，4，5-三磷酸肌醇受体1（IP₃R1）、兰尼碱受体2（RyR2）mRNA表达；激光共聚焦显微镜观察细胞质中的游离钙离子浓度。结果: IGRS预处理可以提高OGD/R细胞存活率、减少LDH释放（均P < 0.01）；降低细胞凋亡率，抑制GRP78、CHOP，Bax和caspase-12蛋白表达（均P < 0.01），上调Bcl-2和Bcl-2/Bax（均P < 0.01），增加细胞SERCA2 mRNA表达（P < 0.01），降低游离钙离子浓度，下调RyR2和IP₃R1 mRNA表达。结论: IGRS具有明确的神经保护作用，可能是通过调节SERCA2维持钙平衡，进而抑制内质网应激介导的细胞凋亡来减轻脑缺血再灌注损伤。

Protective effect of iridoid glycosides of radix scrophulariae on endoplasmic reticulum stress induced by oxygen-glucose deprivation and reperfusion in vitro model

Objective: To investigate the regulatory effect of iridoid glycoside of radix scrophulariae (IGRS) on endoplasmic reticulum stress induced by oxygen-glucose deprivation and reperfusion in vitro model. Methods: Rat pheochromocytoma PC12 cells were pretreated with IGRS (50, 100, 200 μg/mL) for 24h, and the in vitro model of oxygen-glucose deprivation/reoxygenation (OGD/R) was applied. The cell viability was determined by MTT and lactate dehydrogenase (LDH) assay. The apoptotic rate was detected by flow cytometry. The expression of B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), C/EBP homologous protein (CHOP), caspase-12 protein, and glucose-regulated protein-78(GRP78)were detected by Western blotting. The mRNA expression levels of sarco/endoplasmic reticulum Ca²⁺-ATPase2 (SERCA2), 1, 4, 5-triphosphate inositol receptor 1 (IP₃R1), and ryanodine receptor 2 (RyR2)were detected by real-time RT-PCR. Free Ca²⁺ concentration Ca²⁺]_i was determined by using laser scanning confocal microscopy. Results: The damage caused by OGD/R to PC12 cells was significantly reduced by IGRS, with significant effect on increasing survival rate and reducing LDH release (all P < 0.01). The expression of GRP78, CHOP, Bax, and caspase-12 were down-regulated (all P < 0.01), and the expression of Bcl-2 and Bcl-2/Bax ratio was up-regulated (all P < 0.01); IGRS increased the expression of SERCA2 mRNA in PC12 cells after OGD/R injury (P < 0.01), decreased Ca²⁺]_i and down-regulated the expression of RyR2 mRNA and IP₃R1 mRNA. Conclusion: IGRS has neuroprotective effect, which may alleviate cerebral ischemia-reperfusion injury by regulating SERCA2, maintaining calcium balance, and inhibiting endoplasmic reticulum stress-mediated apoptosis.