Published online Dec 7, 2017. doi: 10.3748/wjg.v23.i45.7989
Peer-review started: July 24, 2017
First decision: August 30, 2017
Revised: October 6, 2017
Accepted: October 17, 2017
Article in press: October 17, 2017
Published online: December 7, 2017
Hydatid disease is caused by Echinococcus granulosus. It is a worldwide zoonosis. It is highly prevalent in Xinjiang, China. The animal disease model is of great significance for the drug development against parasite disease.
Echinococcosis is mostly caused by close contact with infected dogs or occupational exposures. The researchers producing hydatid disease model have the high risk of infection because they handle parasite eggs to feed animals through oral route.
To avoid contamination risk of handling parasite eggs, this study investigated a safer way for developing an experimental murine model of cystic echinococcosis in the liver.
Bypassing the oral feeding of contaminant parasite eggs, human protoscolices were injected via the portal vein. Using this method, the tapeworm eggs that may contaminate lab and consequently enable transmission to human beings are avoided.
The pathological results confirmed that protoscolices kept alive and moved from the portal vein into different liver segments and lobes, and the three different protoscolice injection concentrations led to different infection rates of 90%, 100%, and 63.6%, respectively.
By sterile injection with human protoscolices via the portal vein, a novel murine model was developed with echinococcosis vacuoles formed in the liver. Without contamination risk to researchers, this disease model is suitable for anti-hydatid treatment trials.
The good experience that can be learnt from this study is the portal vein injection, which can bypass the oral feeding with parasite eggs. The protoscolices migrate in the portal vein with blood flow, settle in the liver, and develop into orthotopic hepatic hydatid cysts, resembling the natural infection route and course. The lesson that can be learnt from this study is protoscolex collection. Only the fresh protoscolex can result in success parasite growth.
With this model, the further anti-hydatid medicines and interventional treatment can be tried. With the quantitative immune results, the effects can be monitored by blood test.
Using standard score calculated as (raw score - mean)/SD, the best injection method has been screened. This value allows comparisons to be made between the three models with different distribution characteristics. The portal vein injection at 200 protoscolices in 100 μL saline is the best method for the future model.