The alleviation of difenoconazole-induced kidney injury in common carp (Cyprinus carpio) by silybin: Involvement of inflammation, oxidative stress, and apoptosis

Abstract

Triazole fungicides, such as difenoconazole (DFZ), are frequently used to control fungus in crops that pollute water. The common carp (Cyprinus carpio) (hereafter referred to as “carp”) is an excellent bio-indicator of water quality. The seeds of the silymarin plant contain a flavonolignan called silybin (SYB), which is used to treat liver disease. To explore SYB's involvement in DFZ-triggered kidney damage in carps, an H&E assay was conducted, and ROS level was also examined. The results demonstrated that SYB alleviated DFZ-induced destruction of kidney tissue structure in carps, as well as alleviating the elevation of kidney ROS level in carps. RT-qPCR and Western blot were used to detect inflammation-, oxidative stress- and apoptosis-related factors at mRNA level and protein level. The experimental findings indicated that relative to the DFZ group, SYB + DFZ co-treatment reduced inflammation-related mRNA level of il-6, il-1β and tnf-α, elevated mRNA level of il-10. It also reduced protein expression levels of NF-κB and iNOS. In addition, SYB + DFZ co-treatment reduced DFZ-induced increase in the oxidative stress-related mRNA indicators sod and cat, and decreased the protein expression levels of Nrf2 and NQO1. SYB reduced the DFZ-induced increase in pro-apoptotic gene Bax mRNA and protein expression levels and the DFZ-induced decrease in anti-apoptotic gene Bcl-2 mRNA and protein expression levels. In summary, SYB potentially mitigates DFZ-induced kidney damage in carp by addressing inflammation, oxidative stress, and apoptosis. Our results establish a theoretical foundation for the clinical advancement of freshwater carp feeds.