Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom.
Vet Parasitol. 2011 Apr 19;177(1-2):79-89. doi: 10.1016/j.vetpar.2010.11.032. Epub 2010 Nov 25.
Eight indoor-reared cross-bred sheep with no prior exposure to Fasciola hepatica were infected by oral gavage with 200 metacercarial cysts of the triclabendazole (TCBZ)-susceptible Cullompton isolate of F. hepatica. Twelve weeks after infection, sheep were treated with 10mg/kg triclabendazole. Two sheep were euthanised per time period; at 48 h, 72 h and 96 h post-treatment (pt). Two untreated control sheep were euthanised at 96 h pt. Flukes were recovered from the liver and, if present, from the gall bladder of the sheep. They were processed for whole mount analysis, histology and transmission electron microscopy of the female reproductive system; specifically, the uterus, vitelline follicles, Mehlis' gland and ovary. Over the 4-day post-treatment period, there was a progressive reduction in the number of oogonia and oocytes in the ovary and evidence of apoptosis. Vacuolation and a decrease in the number of Mehlis' gland cells were observed from 48 h pt onwards and disruption of the normal role of the gland in egg formation was evident. The vitelline follicles showed a gradual decrease in size and became vacuolated; the population structure in each follicle changed to be one consisting mainly of mature cells and the production of shell protein material declined. The follicle became disorganised as the cells broke down and released their contents into the lumen of the follicle. While the uterus appeared to contain eggs at 48 h pt in whole-mount specimens, no properly-formed eggs were observed in histological sections. By 96 h pt, the uterus was completely devoid of eggs. Overall, egg production was seen to be severely affected by TCBZ treatment and flukes were incapable of producing normal eggs within 2 days of treatment. The implications of this in terms of the epidemiology of the disease are discussed.
八只未曾接触过肝片吸虫的室内饲养杂交绵羊通过口服灌胃感染了 200 个对三氯苯达唑（TCBZ）敏感的库伦普顿分离株的肝片吸虫毛蚴囊。感染后 12 周，绵羊用 10mg/kg 的三氯苯达唑进行治疗。每个时间点都有两只绵羊被安乐死；在治疗后 48 小时、72 小时和 96 小时（pt）。两只未治疗的对照绵羊在 96 小时 pt 时被安乐死。从绵羊的肝脏中，如果有，从胆囊中回收吸虫。它们被用于整体分析、组织学和雌性生殖系统的透射电子显微镜检查；具体来说，是子宫、卵黄滤泡、梅利斯氏腺和卵巢。在治疗后 4 天内，卵巢中的卵原细胞和卵母细胞数量逐渐减少，并出现细胞凋亡。从 48 小时 pt 开始，观察到卵黄滤泡中的空泡形成和梅利斯氏腺细胞数量减少，并且腺体在卵子形成中的正常作用受到干扰。卵黄滤泡逐渐变小并变得空泡化；每个滤泡中的细胞群体结构发生变化，主要由成熟细胞组成，壳蛋白物质的产生减少。滤泡解体，细胞破裂，将其内容物释放到滤泡腔中。虽然在整个 mounts 标本中，子宫在 48 小时 pt 时似乎含有卵子，但在组织学切片中没有观察到正常形成的卵子。到 96 小时 pt，子宫完全没有卵子。总的来说，卵子的产生被 TCBZ 治疗严重影响，并且在治疗后 2 天内，吸虫无法产生正常的卵子。本文讨论了这在疾病流行病学方面的意义。
