【摘要】 目的　比较曼氏血吸虫吡喹酮敏感株与抗性株尾蚴阶段对吡喹酮的反应性 ,旨在运用敏感株与抗性株反应性间的差异 ,建立现场监测吡喹酮抗性的方法。方法　将各虫株尾蚴分别暴露于10 - 4、10 - 5、6× 10 - 7、4× 10 - 7m ol/ L吡喹酮溶液中 ,0、2 0、4 0、6 0、80、10 0 min后 ,解剖镜下观察尾蚴的泳动、收缩和断尾率的变化。结果　尾蚴暴露于 10 - 4m ol/ L吡喹酮中即刻停止泳动、沉底并伴有强直性收缩 ;5 min后开始出现体与尾部不协调的快速蠕动 ,尾蚴体区的后端与尾部的前端发生分离即断尾 ,敏感株断尾尾蚴明显多于抗性株 ;暴露于 10 - 5mol/ L吡喹酮中 4 0、6 0、80 m in和 10 0 min后 ,敏感株尾蚴的断尾率分别为 2 8.2 %、5 2 .7%、6 7.5 %和 78.0 % ;抗性株分别为 11.3%、2 8.6 %、39.3%和 4 5 .5 %。暴露于 4× 10 - 7m ol/ L中 80 min和 10 0 min后 ,敏感株尾蚴的断尾率为 10 .3%和 17.0 % ;抗性株为 0 .5 %和 1.1%。结论　曼氏血吸虫吡喹酮抗性株和敏感株尾蚴阶段对吡喹酮反应性存在非常显著的差异。提示 ,将尾蚴移入 4× 10 - 7mol/ L吡喹酮溶液中 80 - 10 0 min,镜下观察其断尾率 ,作为曼氏血吸虫对吡喹酮敏感性的检测方法 ,可用于螺体内吡喹酮抗性虫株的现场监测。更多还原

【Abstract】 Objective To develop a test to monitor for the presence of praziquantel-resistant worms in snails collected from the field, by comparing the responses of cercariae of praziquantel-resistant and -susceptible S. mansoni to praziquantel.Methods Cercariae of various isolates of S. mansoni were exposed in 10 -4,10 -5,6×10 -7 and 4×10 -7 mol/L praziquantel. Changes in the patterns of behavior, including swimming, constriction and tail shedding were observed under dissecting microscope at 0, 20, 40, 60,80 and 100 minutes after adding praziquantel. The number of cercariae which had shed tails were counted. Results When the cercariae from both susceptible and resistant isolates were exposed to 10 -4 mol/L praziquantel they immediately ceased swimming, sank to the bottom and exhibited very strong constrictions. Five minutes late, the body and tail of the cercariae wriggled rapidly but insufficiently to swim. Separation of the bodies and tails then occurred. The percents of tail shedding of cercariae of susceptible isolates were higher than those of resistant isolates. When cercariae were exposed to 10 -5 mol/L praziquantel over 40, 60,80 and 100 minutes, 28.2%, 52.7%, 67.5% and 78.0% of cercariae from susceptible isolates shed their tails respectively, while only 11.3%, 28.6%, 39.3% and 45.5% of cercariae from resistant isolates shed their tails respectively. When cercariae were exposed to 4×10 -7 mol/L praziquantel over 80 and 100 minutes, 10.3% and 17.0% of cercariae from susceptible isolates shed their tails, while only 0.5% and 1.1% of cercariae from resistant isolates shed their tails respectively. Conclusion There were significant differences in responses to praziquantel at the cercarial stage of S. mansoni between praziquantel-susceptible and -resistant isolates. The difference of tail shedding rates of cercariae between resistant and susceptible isolates following exposure to 4×10 -7 mol/L praziquantel for 80-100 minutes could be used to monitor for the presence of praziquantel-resistant worms in infected snails collected from the field.更多还原