Reactive oxygen species mediate autophagy in the regulation of ivermectin resistance in Haemonchus contortus

The development of anthelmintic resistance due to long-term and irregular use of drugs such as ivermectin (IVM) poses a major challenge to the prevention and control of haemonchosis caused by Haemonchus contortus. However, the mechanism of IVM resistance in H. contortus remains incompletely understood. Reactive oxygen species (ROS) generated under oxidative stress conditions serve as key regulators of autophagy. Reactive oxygen species induce autophagy, and autophagy mitigates oxidative stress-mediated damage, thereby enhancing cell survival. Although autophagy is known to contribute to H. contortus resistance, the involvement of ROS and autophagy in H. contortus resistance remains unclear. This study explores the regulatory role of ROS-mediated autophagy in H. contortus resistance to IVM, using sensitive and resistant strains as experimental subjects, with resistance assessed via larval migration inhibition tests and RT-qPCR, autophagy levels detected by RT-qPCR and transmission electron microscopy, and ROS levels determined by the DCFH-DA fluorescence probe assay. Results showed that baseline ROS levels were higher in the resistant strain than in the sensitive strain, and IVM treatment increased ROS levels in the sensitive strain (P < 0.05). After N-acetyl-L-cysteine (NAC)-mediated inhibition of ROS, autophagy levels and IVM resistance in the resistant strain were substantially reduced. Lipopolysaccharide (LPS)-induced upregulation of ROS led to substantial increases in autophagy levels and IVM resistance in the sensitive strain. The study demonstrates that ROS may enhance H. contortus resistance to IVM by inducing autophagy. This research shows a potential relationship between ROS, autophagy, and IVM resistance, providing insights into the mechanisms underlying resistance in H. contortus.