Analysis of P-gp genes relative expression associated to ivermectin resistance in larval stages from cultures (L and xL) and from gerbils () (L) as models of study.

The aim of the study was to compare the relative gene expression of P-glycoprotein genes () between fourth (L), infective (L), and transitory infective (xL) larval stages as laboratory models to study ivermectin (IVM) resistance. The resistant to IVM (IVMr) and susceptible to IVM (IVMs) strains were used to develop xL culture and to infect (gerbils) to collect L stages. Morphometric differences were evaluated from 25 individuals of from each strain. Relative gene expression from xL and L was determined between comparison of IVMr stages and from IVMr IVMs stages. Seven genes (1, 2, 3, 4, 9, 10, and 16) were analysed by RT-qPCR using L stage as control group, per strain, and and as constitutive genes. Morphological changes were confirmed between xL and L developing oral shape, oesophagus, and intestinal tube. In addition, the body length and width showed statistical differences ( < 0.05). The 1, 2, 3, and 4 genes ( < 0.05) were upregulated from 7.1- to 463.82-fold changes between IVMr stages, and (13.12-fold) and (13.56-fold) genes showed differences between L and xL, respectively. The comparative study between IVMr IVMs strains associated to xL and L displayed significant upregulation for most of the genes among 4.89-188.71 fold-change. In conclusion, these results suggest the use of xL and L as suitable laboratory models to study IVMr associated with genes to contribute to the understanding of anthelmintic resistance.