大黄素对海人酸致痫小鼠海马神经细胞保护作用机制的研究

Mechanism of action of emodin in the protection of hippocampal neurons in mice with epilepsy induced by kainic acid

摘要:

目的 研究大黄素对小鼠癫痫持续状态后Toll样受体4（TLR4）-髓样分化因子88（MyD88）-核因子κB（NF-κB）炎性信号通路表达的影响，探讨大黄素对海人酸致痫小鼠海马神经细胞保护作用的机制。方法 54只ICR雄性小鼠随机分为对照组、癫痫持续状态（SE）组、大黄素治疗组（200 mg/kg），每组18只。采用腹腔内注入海人酸建立小鼠癫痫持续状态模型。通过行为学观察小鼠癫痫发作后的行为学改变；尼氏染色观察小鼠海马组织神经细胞的坏死情况；RT-PCR、Western blotting检测TLR4、MyD88、NF-κB mRNA和蛋白的表达量。结果 大黄素干预后小鼠癫痫的发作级别及发作次数降低；海马组织神经细胞的坏死减轻（P<0.05）；同时海马组织中TLR4、MyD88、NF-κB mRNA和蛋白的表达下调（P<0.05）。结论 小鼠癫痫持续状态后可激活TLR4-MyD88-NF-κB炎性信号通路，通过大黄素干预后，TLR4-MyD88-NF-κB炎性信号通路的mRNA和蛋白表达下调。大黄素对海人酸致痫小鼠海马神经细胞保护作用的机制可能与其抑制TLR4-MyD88-NF-κB炎性信号通路表达有关。

Abstract:

Objective To investigate the effect of emodin on the expression of the Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-nuclear factor kappa-B (NF-κB) inflammatory signaling pathway after status epilepticus (SE) in mice, as well as the mechanism of action of emodin in protecting hippocampal neurons in mice with epilepsy induced by kainic acid. Methods A total of 54 male ICR mice were randomly divided into control group, SE group, and emodin group (200 mg/kg), with 18 mice in each group. A mouse model of SE was established by intraperitoneal injection of kainic acid. The behavioral changes of mice after epileptic seizure were observed; Nissl staining was used to observe the necrosis of hippocampal neurons; RT-PCR and Western blotting were used to measure the mRNA and protein expression of TLR4, MyD88, and NF-κB. Results Emodin intervention significantly reduced the severity and number of seizures, alleviated the necrosis of hippocampal neurons (P<0.05), and downregulated the mRNA and protein expression of TLR4, MyD88, and NF-κB in the hippocampus (P<0.05). Conclusions The TLR4-MyD88-NF-κB inflammatory signaling pathway is activated after SE in mice, and the mRNA and protein expression of the TLR4-MyD88-NF-κB inflammatory signaling pathway is downregulated after emodin intervention. Emodin can exert a protective effect on hippocampal neurons in mice with epilepsy induced by kainic acid, possibly by inhibiting the expression of the TLR4-MyD88-NF-κB inflammatory signaling pathway.