中文摘要：

目的研究中缅边境恶性疟原虫对青蒿素类药物抗药机制。方法收集分离自2008—2010年中缅边境确诊为恶性疟病人体内的疟原虫,共34株,进行体外培养;提取原虫血DNA,采用聚合酶链式反应（PCR）方法,扩增PF3D7-1343700（K-13）基因,对目标基因进行全基因测序,检测K-13基因变异情况;依据基因有无变异分为两组,对比两个组别疟原虫对3种抗疟药青蒿琥酯（Artesunate,AS）、双氢青蒿素（Dihydroartemisinine,DHA）和青蒿素（artemisinin,ART）的半效抑虫浓度（IC50值）,并与野生株3D7做对比;随后将这些疟原虫在环状体时期暴露于大剂量的DHA下,6h后洗尽药物,再经过66h培养后涂片,计算生存率（RSA）,比较变异株和非变异株之间有无差异。结果检测发现疟原虫K13基因存在137-142位点NN插入（占82.4%）,另有E252Q、F446I、C469Y、R539T、P553L、P574L、H719N位点突变,均伴有NN插入,其中F446I（占44.1%）。病人株的IC50值和野生株无统计学差异（P〉0.05）,但病人株的RSA高于野生株（P〈0.05）;有K13基因变异组和无变异组对AS、DHA、ART的IC50值无统计学差异（P〉0.05）,但有基因变异组的RSA高于无基因变异组（P〈0.05）。结论本研究结果发现K-13基因变异与恶性疟原虫对青蒿素类药物抗药性可能相关。

英文摘要：

This study aims to evaluate drug resistance mechanism to artemisinin derivatives in Plasmodium falciparum.The parasites of patients collected from the China-Myanmar border from 2008 to 2010were cultured in vitro,and DNAs were extracted.The full-length of K13 gene was sequenced in all samples using polymerase chain reaction and direct sequencing methods.To measure drug susceptibilities in artesunate（AS）,dihydroartemisinin（DHA）and artemisinin（ART）,we calculated the50%inhibitory concentrations（IC50s）.Parasites were exposed to high-dose of dihydroartemisinin in ring stage for 6hours,and the survival rates of the ring stage（RSA）was calculated after 66 hours.We found that there were no difference in IC50 s in patient isolates and Standard strain-3D7,and RSA in parasite isolates was significantly higher than 3D7.Sever point mutations（E252Q F446IC469 Y R539T P553 L P574L H719N）were identified in58.8% of the parasite isolates,and F446 Imutation predominated in 44.1% of the parasite isolates.NN-insert mutation predominated in 82.4%,the total point mutations were accompanied by NN-insert.All sample were divided into two groups：gene mutation and no-mutation.We found that there were no difference in IC50 in gene mutation and no-mutation in K-13,and RSA in parasite isolates with K13 mutations was significantly higher than that in wild-type isolates.This result suggest that K13 mutations were possible correlated with artemisinin resistance.