McConville M, Brennan G P, Flanagan A, Edgar H W J, McCoy M, Castillo R, Hernández-Campos A, Fairweather I
Parasite Proteomics and Therapeutics Research Group, Queens University Belfast, United Kingdom.
Vet Parasitol. 2008 May 6;153(1-2):52-64. doi: 10.1016/j.vetpar.2008.01.022. Epub 2008 Jan 20.
Eight indoor-reared, crossbred sheep with no pre-exposure to Fasciola hepatica were infected, by oral gavage, with 200 metacercarial cysts of the triclabendazole-susceptible, Cullompton isolate of F. hepatica. Anthelmintic dosing occurred at 4 weeks post-infection using 15mg/kg compound alpha. Two treated sheep per time period were euthanized at 24h, 48h and 72h post-treatment with compound alpha. The two sheep from the control group were euthanized alongside the 24h alpha-treated sheep. Juvenile flukes were recovered from each of the sheeps' liver and processed for examination by electron microscopy. The surface morphology of the flukes' tegument was assessed using scanning electron microscopy (SEM). The ultrastructure of the tegumental syncytium and underlying tegumental cells and connections and somatic musculature were investigated using transmission electron microscopy (TEM). Both the SEM and TEM results revealed a level of disruption that increased with time, culminating at 72h with extensive tegumental loss and substantial degeneration of the cell bodies. The effects of compound alpha on the surface morphology were not particularly apparent until 48h post-treatment, when disruption included swelling and blebbing of the tegument. At 72h post-treatment, SEM revealed loss of the entire syncytial layer over large areas of the flukes. In the areas where the syncytium was lost and the basal lamina exposed, lesions of varying sizes had developed, revealing underlying tissues. Though minor forms of disruption to the ultrastructure of the syncytium were observed using TEM 24h post-treatment, it was at 48h post-treatment that substantial stress responses occurred. They included the presence of autophagic vacuoles and 'open' bodies at the apex of the syncytium and swelling of the basal infolds. The mitochondria within the syncytium and tegumental cells became progressively more disrupted over the three time periods and, by 72h post-treatment, they were frequently distorted and swollen in appearance, and contained severely swollen cristae. By 72h, the number of secretory bodies, particularly T1 bodies, had become significantly depleted in their respective cell bodies, cytoplasmic processes and in the tegumental syncytium. Both the circular and longitudinal muscle bundles were severely disrupted 72h post-treatment. They frequently contained a reduced number of muscle fibres and, in more severe instances, there was an absence of fibres altogether.
选取8只室内饲养、未曾预先接触过肝片吸虫的杂交绵羊，通过口服灌喂，使其感染200个对三氯苯达唑敏感的肝片吸虫库洛姆普顿分离株的囊蚴。在感染后4周，使用15mg/kg复方α进行驱虫给药。在使用复方α治疗后24小时、48小时和72小时，每个时间段对2只治疗后的绵羊实施安乐死。对照组的2只绵羊与24小时接受α治疗的绵羊一同实施安乐死。从每只绵羊的肝脏中回收未成熟吸虫，并进行处理以便通过电子显微镜检查。使用扫描电子显微镜（SEM）评估吸虫皮层的表面形态。使用透射电子显微镜（TEM）研究皮层合胞体以及下方皮层细胞、连接结构和体壁肌肉组织的超微结构。SEM和TEM结果均显示，破坏程度随时间增加，在72小时时达到顶峰，表现为广泛的皮层缺失和细胞体的大量退化。直到治疗后48小时，复方α对表面形态的影响才特别明显，此时破坏包括皮层肿胀和起泡。治疗后72小时，SEM显示吸虫大面积区域的整个合胞体层缺失。在合胞体缺失且基膜暴露的区域，出现了大小不一的病变，露出了下层组织。虽然在治疗后24小时使用TEM观察到合胞体超微结构有轻微的破坏形式，但在治疗后48小时才出现大量应激反应。这些反应包括在合胞体顶端出现自噬泡和“开放”体以及基底褶皱肿胀。在这三个时间段内，合胞体和皮层细胞内的线粒体逐渐受到更严重的破坏，到治疗后72小时，它们的外观经常扭曲和肿胀，嵴严重肿胀。到72小时时，分泌体，特别是T1体，在其各自的细胞体、细胞质突起和皮层合胞体中的数量已显著减少。治疗后72小时，环形和纵行肌束均受到严重破坏。它们通常含有数量减少的肌纤维，在更严重的情况下，完全没有肌纤维。
