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Disruption of vitellogenesis and spermatogenesis by triclabendazole (TCBZ) in a TCBZ-resistant isolate of Fasciola hepatica following incubation in vitro with a P-glycoprotein inhibitor

Published online by Cambridge University Press:  24 April 2014

J. SAVAGE ,
M. MEANEY ,
G. P. BRENNAN ,
E. HOEY ,
A. TRUDGETT  and
I. FAIRWEATHER
J. SAVAGE
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland
M. MEANEY
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland
G. P. BRENNAN
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland
E. HOEY
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland
A. TRUDGETT
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland
I. FAIRWEATHER*
Affiliation:
Parasite Therapeutics Research Group, School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland
*
* Corresponding author: School of Biological Sciences, Medical Biology Centre, The Queen's University of Belfast, 97 Lisburn Road, Belfast, BT9 7BL, Northern Ireland. E-mail: i.fairweather@qub.ac.uk
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Summary

A study has been carried out to investigate whether the action of triclabendazole (TCBZ) against Fasciola hepatica is altered by inhibition of P-glycoprotein (Pgp)-linked drug efflux pumps. The Sligo TCBZ-resistant fluke isolate was used for these experiments and the Pgp inhibitor selected was R(+)-verapamil [R(+)-VPL]. In the first experiment, flukes were initially incubated for 2 h in R(+)-VPL (100 μ m), then incubated in R(+)-VPL+triclabendazole sulphoxide (TCBZ.SO) (50 μg mL−1, or 133·1 μ m) until flukes ceased movement (at 9 h post-treatment). In a second experiment, flukes were incubated in TCBZ.SO alone and removed from the incubation medium following cessation of motility (after 15 h). In the third experiment, flukes were incubated for 24 h in R(+)-VPL on its own. Changes to the testis tubules and vitelline follicles following drug treatment and following Pgp inhibition were assessed by means of light microscope histology and transmission electron microscopy. Incubation of the Sligo isolate in either R(+)-VPL or TCBZ.SO on their own had a limited impact on the morphology of the two tissues. Greater disruption was observed when the drugs were combined, in terms of the block in development of the spermatogenic and vitelline cells and the apoptotic breakdown of the remaining cells. Sperm formation was severely affected and abnormal. Large spaces appeared in the vitelline follicles and synthesis of shell protein was disrupted. The results of this study support the concept of altered drug efflux in TCBZ-resistant flukes and indicate that drug transporters may play a role in the development of drug resistance.

Keywords

Fasciola hepaticaliver fluketriclabendazole resistanceR(+)-verapamilP-glycoproteintransmission electron microscopy
Type
Research Article
Information
Parasitology , Volume 141 , Issue 8 , July 2014 , pp. 1064 - 1079
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Copyright © Cambridge University Press 2014 

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