Genome-wide mining of gpx gene family provides new insights into cadmium stress responses in common carp (Cyprinus carpio)

Glutathione peroxidase (Gpx) is an important member of antioxidant enzymes, which can play a vital role in metabolizing reactive oxygen species (ROS) and in maintaining cell homeostasis. In order to study the evolutionary dynamics of gpx gene family in allotetraploid fish species, we identified a total of 14 gpx genes in common carp Cyprinus carpio, while 9 gpx genes were discovered in the diploid progenitor-like species Poropuntius huangchuchieni. Comparative genomic analysis and phylogenetic analysis revealed that the common carp gpx genes had significant expansion and were divided into five distinct subclades. Exon-intron distribution patterns and conserved motif analysis revealed highly conserved evolutionary patterns. Transcript profiles suggested that different gpx genes had specific patterns of regulation during early embryonic development. In adult tissues, gpx genes had a relatively broad expression distribution, most of which were highly expressed in the gills, intestines, and gonads. RT-qPCR studies showed that most gpx genes were downregulated during the initial cd²⁺ treatment stage. Dietary supplementation of Bacillus coagulans at different concentrations (Group 2 of 1.0 × 10⁷ cfu/g, Group 3 of 1.0 × 10⁸ cfu/g, and Group 4 of 1.0 × 10⁹ cfu/g) induced different regulatory responses of gpx subclades. This result suggested that the appropriate concentration of B. coagulans can improve gpx gene expression when exposed to heavy metal cadmium treatment, which may play a vital role in the resistance to oxidative stress and immune responses. This study has expanded our understanding of the functional evolution of the gpx gene family in common carp.

Astragaloside IV attenuates cadmium induced nephrotoxicity in rats by activating Nrf2

Acute kidney injury (AKI) has become a disease of global concern due to its high morbidity and mortality. This has highlighted the need for renoprotective agents. Astragaloside IV (AS-IV) is a saponin isolated from Astragalus membranaceus with good antioxidant, anti-inflammatory and anti-tumor properties. In this study, HK2 cells and rat model were utilized to explore the protective effect of AS-IV against cadmium chloride-induced oxidative stress-induced apoptosis. CdCl2-induced apoptosis, ROS production, and mitochondrial membrane potential alterations were significantly inhibited in AS-IV -treated HK2 cells. Expression of the mitochondria-associated apoptotic proteins Cleaved-Caspase3, Cleaved-Caspase9, and Cleaved-PARP was significantly reduced after AS-IV intervention. In addition, AS-IV inhibited Rat weight loss and also alleviated the symptoms of CdCl2-induced nephrotoxicity in a rat model of CdCl2-induced kidney injury. Further experiments showed that AS-IV suppresses heavy metal Cd-induced mitochondria-mediated apoptosis by regulating the Nrf2/HO-1 pathway. In conclusion, AS-IV could protect the kidney from heavy metal-induced toxicity and could be used as a nephroprotective agent.