ERK1/2通路介导米诺环素促进PC12细胞氧糖剥夺后血红素加氧酶-1的表达

ERK1/2 signaling pathway mediates heme oxygenase-1 up-regulation by minocycline in PC12 cells exposed to oxygen glucose deprivation

目的探讨米诺环素（minocycline,MC）对大鼠肾上腺嗜铬细胞瘤细胞（PC12）缺氧缺糖（oxygen glucose deprivation,OGD）损伤的保护作用及其机制。方法采用氧糖剥夺6 h方法建立PC12细胞缺氧缺糖损伤模型,并将细胞随机分为正常对照组、模型组、米诺环素组及MEK1/2抑制剂组,在OGD/复氧24 h后,采用MTT比色法测定PC12细胞的存活率,Western blotting法检测血红素加氧酶-1（HO-1）及胞外信号调节蛋白激酶1/2（ERK1/2）的磷酸化水平。结果 OGD组PC12细胞存活率显著低于正常对照组,米诺环素（0.1~10μmol/L）能缓解OGD损伤导致细胞存活率的下降,同时上调HO-1蛋白的表达及增加ERK1/2的磷酸化水平,其中1μmol/L浓度最佳。其次,ERK1/2上游激酶MEK1/2特异性抑制剂U0126（10μmol/L）能阻断米诺环素诱导HO-1蛋白表达的增加。结论米诺环素可减轻OGD导致PC12细胞的损伤并上调抗氧化蛋白HO-1的表达,其作用机制可能与激活ERK1/2信号通路有关。

Objective To investigate the effects of minocycline in promoting the survival of pheochromocytoma（PC12） cells exposed to oxygen glucose deprivation（OGD） and explore the underlying mechanisms. Methods An in vitro cell model of cerebral ischemia was established by OGD for 6 h in PC12 cells with pretreatment with minocycline or an ERK1/2 inhibitor. At24 h after OGD injury, the cells were evaluated for cell viability by MTT assay and expressions of heme oxygenase- 1（HO- 1）and phospholylated extracellular signal- regulated protein kinase 1/2（ERK1/2） by Western blotting. Results The cell viability decreased dramatically following OGD. Pretreatment with minocycline（0.1- 10 μmol/L） induced a significant increase in the cell viability after OGD and caused up-regulation of HO-1 protein and enhanced ERK1/2 phospholylation, and the effects were especially obvious with 1 μmol/L minocycline and were abolished by inhibition of ERK1/2 activity with U0126（10 μmol/L）.Conclusion Minocycline can protect PC12 cells against OGD- induced toxicity by up- regulating HO- 1 protein expression through ERK1/2 signaling pathways.