Garcia-Campos Andres, Baird Alan W, Mulcahy Grace
School of Veterinary Medicine,University College Dublin,Veterinary Sciences Centre,Belfield,Dublin 4,Ireland.
Parasitology. 2016 Jan;143(1):24-33. doi: 10.1017/S0031182015001481. Epub 2015 Nov 2.
Fasciola hepatica is a parasitic trematode that causes serious losses to livestock producers, and also zoonotic disease. The limitations of chemotherapy for the control of fasciolosis have led to significant interest in the development of vaccines to protect cattle and sheep from infection. However, relatively few studies have concentrated on the mechanisms of invasion of the gut by newly excysted juvenile liver flukes (NEJ) and the host response triggered by this event. The aim of this work was to develop an in vitro model to study invasion by NEJ, while also reducing the requirement for challenge infections of experimental animals. Fasciola hepatica metacercariae were excysted in vitro and placed into compartments containing rat distal jejunal sheets. Variations in incubation medium, chamber size and incubation temperature were used to identify optimal conditions for NEJ migration across the gut. Histological examination showed increased migration until 120 min post-incubation. The use of RPMI, without gassing at 39 °C, as the incubation medium was found to be optimal, with 40·5% of NEJ migrating after 150 min. This study describes a readily-reproducible method for studying the migration of F. hepatica NEJ within the definitive host. It will be useful for identifying potential drug and vaccine targets.
肝片吸虫是一种寄生性吸虫,会给牲畜养殖户造成严重损失,还会引发人畜共患病。化学疗法在控制肝片吸虫病方面存在局限性,这使得人们对开发保护牛羊免受感染的疫苗产生了浓厚兴趣。然而,相对较少的研究集中在新脱囊的肝片吸虫幼虫(NEJ)侵入肠道的机制以及这一事件引发的宿主反应上。这项工作的目的是建立一个体外模型来研究NEJ的侵入,同时减少对实验动物进行攻毒感染的需求。肝片吸虫囊蚴在体外脱囊,并置于含有大鼠空肠远端肠片的隔室中。通过改变孵育培养基、腔室大小和孵育温度来确定NEJ穿过肠道的最佳条件。组织学检查显示,孵育后120分钟内迁移增加。发现使用RPMI培养基,在39°C下不进行通气作为孵育培养基是最佳的,150分钟后有40.5%的NEJ迁移。本研究描述了一种易于重现的方法,用于研究肝片吸虫NEJ在终末宿主体内的迁移。它将有助于确定潜在的药物和疫苗靶点。