Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, Ireland.
Exp Parasitol. 2013 Nov;135(3):642-53. doi: 10.1016/j.exppara.2013.09.015. Epub 2013 Oct 1.
A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Sligo TCBZ-resistant fluke isolate was used for these experiments and the Pgp inhibitor selected was R(+)-verapamil [R(+)-VPL]. In the first experiment, flukes were initially incubated for 2h in R(+)-VPL (1×10(-4) M), then incubated in R(+)-VPL + triclabendazole sulphoxide (TCBZ.SO) (50μg/ml) until flukes ceased movement (at 9h post-treatment). In a second experiment, flukes were incubated in TCBZ.SO alone and removed from the incubation medium following cessation of motility (after 15h). In the third experiment, flukes were incubated for 24h in R(+)-VPL on its own. Changes to the tegumental system and gut following drug treatment and following Pgp inhibition were assessed by means of light microscope histology and transmission electron microscopy. Incubation of the Sligo isolate in either R(+)-VPL or TCBZ.SO on their own had a limited impact on the tegumental syncytium and tegumental cells; the changes were consistent with a stress response by the fluke to drug action. Greater disruption was observed when the drugs were combined, in terms of the vacuolation and sloughing of the syncytium, spine disruption and the cessation of secretory activity in, and degradation of, the tegumental cells. In the gut, treatment with R(+)-VPL on its own did not lead to any cellular changes. Some limited changes to the mitochondria and the granular endoplasmic reticulum were observed after incubation in TCBZ.SO alone, together with reduced secretory activity and evidence of autophagy. However, these changes were far more pronounced in combination-treated flukes. The results of this study support the concept of altered drug efflux in TCBZ-resistant flukes and indicate that drug transporters may play a role in the development of drug resistance.
一项研究旨在探讨三氯苯达唑（TCBZ）对肝片吸虫的作用是否因抑制 P-糖蛋白（Pgp）相关药物外排泵而改变。这些实验使用了来自斯莱戈的 TCBZ 耐药吸虫分离株，选择的 Pgp 抑制剂是 R(+)-维拉帕米[R(+)-VPL]。在第一个实验中，吸虫最初在 R(+)-VPL（1×10(-4) M）中孵育 2 小时，然后在 R(+)-VPL +三氯苯达唑亚砜（TCBZ.SO）（50μg/ml）中孵育，直到吸虫停止运动（处理后 9 小时）。在第二个实验中，单独孵育 TCBZ.SO，在运动停止后（15 小时后）从孵育培养基中取出吸虫。在第三个实验中，吸虫单独在 R(+)-VPL 中孵育 24 小时。药物处理和 Pgp 抑制后，通过光镜组织学和透射电子显微镜评估了表皮系统和肠道的变化。单独孵育斯莱戈分离株的 R(+)-VPL 或 TCBZ.SO 对表皮合胞体和表皮细胞的影响有限；这些变化与吸虫对药物作用的应激反应一致。当药物联合使用时，合胞体的空泡化和脱落、棘突破坏以及表皮细胞的分泌活动停止和降解观察到更大的破坏。在肠道中，单独使用 R(+)-VPL 治疗不会导致任何细胞变化。单独孵育 TCBZ.SO 后观察到线粒体和颗粒内质网的一些有限变化，同时分泌活动减少，有自噬证据。然而，在联合处理的吸虫中，这些变化更为明显。这项研究的结果支持耐药吸虫中药物外排改变的概念，并表明药物转运体可能在耐药性的发展中起作用。
