背景:蠕虫病和对商业驱虫药化合物的抗性是牲畜生产者经济损失的主要原因,因此迫切需要能够检测潜在活性产物的新药和可靠的体外筛选试验。考虑到这一点,一系列新颖的苯并咪唑衍生物(5-甲基苯并咪唑1,2-二取代,5-羧基苯并咪唑,5-甲基苯并咪唑2-酮)在鞘外鞘L3(xL3)和斑马鱼(Kirby驱虫易感McMaster分离株)的成年阶段进行了筛选。
方法:这项工作介绍了使用红外跟踪设备(WMicrotrackerOne)对H.contortus的xL3阶段进行自动运动测定的设置,以及幼虫发育测试(xL3至L4)和对H.contortus成年阶段的运动测定。使用具有不同作用机制的商业驱虫药对这些体外测定的敏感性进行了比较研究,还评估了一系列新型苯并咪唑衍生物的驱虫活性。
结果:自动xL3测定具有能够同时分析许多化合物的巨大优势,但它显示了灵敏度较低的局限性,与成人运动或发育测定所需的相比,需要更高浓度的商业驱虫药。尽管新的1,2,5-三取代苯并咪唑衍生物都不能显着降低xL3s的运动性,其中之一(1e)显着影响xL3s到L4的发展,以及五个新化合物(1b,1d,1e,2a和2c)降低了H.contortus成虫期的运动性。
结论:对结果的分析强烈表明,体外xL3至L4发育试验,特别是L4阶段,对于所选择的商业驱虫药,可能更接近H.contortus成年阶段的药理学敏感性(感兴趣的目标),不同的作用机制,和用于测定的苯并咪唑衍生物系列。因此,正在建立使用红外跟踪设备的L4自动运动性测定。将进行进一步的研究以评估最具活性的新型苯并咪唑衍生物的体内驱虫活性。
BACKGROUND: Helminthiasis and resistance to commercial anthelmintic compounds are major causes of economic losses for livestock producers, resulting in an urgent need for new drugs and reliable in vitro screening tests capable of detecting potentially active products. Considering this, a series of novel benzimidazole derivatives (5-methylbenzimidazole 1,2-disubstituted, 5-carboxybenzimidazole, 5-methylbenzimidazole 2-one) was screened on exsheathed L3 (xL3) and on the adult stage of Haemonchus contortus (Kirby anthelmintic-susceptible McMaster isolate).
METHODS: This work presents the set-up of an automated motility assay on the xL3 stage of H. contortus using an infrared tracking device (WMicrotracker One) together with a larval development test (xL3 to L4) and a motility assay on the adult stage of H. contortus. A comparative
study of the sensitivity of these in vitro assays using commercial anthelmintics with different mechanisms of action was carried out, also evaluating anthelmintic activity of a series of novel benzimidazole derivatives.
RESULTS: The automated xL3 assay had the great advantage of being able to analyze many compounds simultaneously, but it showed the limitation of having lower sensitivity, requiring higher concentrations of the commercial anthelmintics tested compared to those needed for the adult motility or development assays. Although none of the novel 1,2,5-tri-substituted benzimidazole derivatives could significantly decrease the motility of xL3s, one of them (1e) significantly affected the development of xL3s to L4, and five new compounds (1b, 1d, 1e, 2a and 2c) reduced the motility of H. contortus adult stage.
CONCLUSIONS: The analysis of the results strongly suggests that the in vitro xL3 to L4 development test, particularly for the L4 stage, could be closer to the pharmacological sensitivity of the adult stage of H. contortus (target of interest) for commercial anthelmintic selected, with different mechanisms of action, and for the series of benzimidazole derivatives assayed. Therefore, an automated motility assay on L4 using the infrared tracking device is being set up. Further studies will be conducted to evaluate the in vivo anthelmintic activity of the most active novel benzimidazole derivatives.