托吡酯对大鼠星形细胞内谷胱甘肽硫转移酶及多药耐受基因的影响

Effects of topiramate on activities of glutathione s-transferase and expression of multidrug resistance gene in astrocytes in vitro

目的 :探讨托吡酯的药物耐受性及其机制。方法 :不同浓度托吡酯持续作用于培养的新生大鼠大脑皮质星形胶质细胞 ,对照组不加药。分别在给药后 5 ,10 ,15和 2 0d ,测定细胞内谷胱甘肽硫转移酶 (GST)的活性 ,在加药后 10和 15d用流式细胞术检测多药耐受基因 (MDR1)标志物P 糖蛋白(Pgp)的表达率 ,并与对照组比较。结果 :对照组细胞内GST的活性在各时间点无差异 (P >0 .0 5 )。加托吡酯 5d时 ,4 0 ,80 ,16 0mg·L- 1组GST活性明显升高 ;加药 10d时 ,各浓度组细胞内GST活性均明显升高 ;10d后GST活性变化无显著意义(P >0 .0 5 ) ,细胞内GST活性随托吡酯浓度的增加有上升趋势。各浓度组在 15d以内Pgp的表达率与对照组比较差异无显著意义 (P >0 .0 5 )。结论 :托吡酯可使GST活性升高 ,且与剂量和时间有关 ,提示其可能有代谢性药物耐受性存在 ,托吡酯对MDR1基因表达无影响 ,表明其与其他抗癫痫药能诱导MDR1表达的作用不同。

AIM: To study the effects of antiepileptic drug—topiramate on the activities of glutathione s-transferase (GST) and the expression of MDR gene in astrocytes in vitro and to explore the drug-resistance and it's mechanism of topiramate. METHODS: Postnatal Wistar rats (within 24 h) astrocyte cell culture was established. Different concentrations of topiramate were added to the culture media. But no drugs were added to the control group. Flow cytometry was used for checking the expression of P-glycoprotein (Pgp) after 10 d and 15 d, and chemical colorimetry was used for checking the activities of GST after 5, 10, 15 and 20 d, and compared with those of control group. RESULTS: The activity of GST had no significant difference in the control group (the normal astrocytes without topiramate) at every time point. At d 5, the GST activity raised to(49.8±s 2.5) U·mg -1 protien and above with 40, 80 and 160 mg·L -1 topiramate and was significantly different compared with that of the control group ( P<0.01). At d 10, the GST activity showed greatly increased (P<0.01) in every concentration of topiramate. After 10 d, the activity of GST had no significant change any longer (P>0.05). The GST activity showed a dose-proportional increase with the concentration of add-on topiramate. The percentage of Pgp in astrocytes had no significant difference in every concentration of topiramate compared with control group at d 10 and d 15 (P>0.05). CONCLUSION: Topiramate can enhance the GST activity in astrocytes in certain duration, and that is related with dose-proportion. This study suggests that topiramate may have the peculiarity of metabolic drug-resistance. There is no influence on the expression of Pgp in culture astrocytes. It indicates that the action of topiramate is different from other antiepileptic drugs which can induce the overexpression of MDR1.