Gong Gu, Yuan Libang, Cai Lin, Ran Maorong, Zhang Yulan, Gong Huaqu, Dai Xuemei, Wu Wei, Dong Hailong
Department of Anesthesia, General Hospital of Chengdu Military Area Command, Chengdu, Sichuan, China.
Department of Anesthesia, the Fourth Military Medical University Xijing Hospital, Xi'an, Shaanxi, China.
PLoS One. 2014 Sep 19;9(9):e105944. doi: 10.1371/journal.pone.0105944. eCollection 2014.
Tetramethylpyrazine (TMP) has been widely used in China as a drug for the treatment of various diseases. Recent studies have suggested that TMP has a protective effect on ischemic neuronal damage. However, the exact mechanism is still unclear. This study aims to investigate the mechanism of TMP mediated ischemic hippocampal neurons injury induced by oxygen-glucose deprivation (OGD). The effect of TMP on hippocampal neurons viability was detected by MTT assay, LDH release assay and apoptosis rate was measured by flow cytometry. TMP significantly suppressed neuron apoptosis in a concentration-dependent manner. TMP could significantly reduce the elevated levels of connexin32 (Cx32) induced by OGD. Knockdown of Cx32 by siRNA attenuated OGD injury. Moreover, our study showed that viability was increased in siRNA-Cx32-treated-neurons, and neuron apoptosis was suppressed by activating Bcl-2 expression and inhibiting Bax expression. Over expression of Cx32 could decrease neurons viability and increase LDH release. Furthermore, OGD increased phosphorylation of ERK1/2 and p38, whose inhibitors relieved the neuron injury and Cx32 up-regulation. Taken together, TMP can reverse the OGD-induced Cx32 expression and cell apoptosis via the ERK1/2 and p38 MAPK pathways.
川芎嗪（TMP）在中国已被广泛用作治疗各种疾病的药物。最近的研究表明，TMP对缺血性神经元损伤具有保护作用。然而，确切机制仍不清楚。本研究旨在探讨TMP介导的氧糖剥夺（OGD）诱导的缺血性海马神经元损伤的机制。通过MTT法检测TMP对海马神经元活力的影响，通过流式细胞术检测乳酸脱氢酶（LDH）释放率和细胞凋亡率。TMP以浓度依赖性方式显著抑制神经元凋亡。TMP可显著降低OGD诱导的连接蛋白32（Cx32）水平升高。用小干扰RNA（siRNA）敲低Cx32可减轻OGD损伤。此外，我们的研究表明，经siRNA-Cx32处理的神经元活力增加，并且通过激活Bcl-2表达和抑制Bax表达来抑制神经元凋亡。Cx32的过表达可降低神经元活力并增加LDH释放。此外，OGD增加细胞外信号调节激酶1/2（ERK1/2）和p38的磷酸化，其抑制剂可减轻神经元损伤和Cx32上调。综上所述，TMP可通过ERK1/2和p38丝裂原活化蛋白激酶（MAPK）途径逆转OGD诱导的Cx32表达和细胞凋亡。
