Deoxynivalenol-induced hepatic and renal injury via pyroptosis under heat stress conditions.

Elevated temperatures impose physiological stress on mammals. Meanwhile, high heat and humidity boost mold growth in feed and bedding, potentially increasing deoxynivalenol (DON) contamination. Heat stress and DON both cause hepatorenal damage, yet their combined effects remain unclear. This study established two sequential mouse models to explore the synergistic impacts of heat stress and DON on hepatorenal injury and pyroptosis. In the heat stress gradient model, mice were subjected to 30°C, 36°C, or 42°C for 2 h per day over a 14-day period. Histopathological analysis demonstrated temperature-dependent hepatorenal damage: hepatic injury markers in liver tissue increased at 36°C and 42°C, whereas renal dysfunction indicators were elevated at 42°C. Tissue reactive oxygen species (ROS) levels rose in a temperature-dependent manner, with male mice exhibiting greater hepatic ROS accumulation than females, and significant renal ROS elevation was observed across all three heat stress temperatures (30°C, 36°C, and 42°C) in kidney tissues. Based on these observations, a combined exposure model was established with male mice divided into four groups: control, heat stress (42°C, 2 h/day), DON (2 mg/kg bw/day), and combined treatment. Heat stress upregulated HSP70 concentration in both liver and kidney, while DON disrupted hepatic and renal glutathione (GSH) homeostasis, each causing hepatorenal structural alterations. The combined group displayed the most severe histopathological and ultrastructural damage in both organs. Notably, hepatic mRNA levels of NLRP3, Caspase-1, and Gasdermin D (GSDMD) were significantly elevated in all treatment groups, whereas renal Caspase-1 and GSDMD mRNA were increased in the heat stress group, and all three genes were elevated in the DON and combined groups. At the protein level, hepatic NLRP3, Caspase-1, GSDMD-N, and ASC were most markedly elevated in the combined group, with synergistic upregulation of Caspase-1 and NLRP3 exceeding both single-stressor groups; a comparable pattern of synergistic NLRP3 protein elevation was also observed in the kidney. These molecular alterations were accompanied by elevated inflammatory cytokines (IL-1β, IL-18, TNF-α) in both hepatic and renal tissues and by aggravated structural damage in both organs in the combined treatment group. Collectively, these findings illustrate that heat stress and DON synergistically aggravate hepatic and renal injury, with pyroptosis pathway activation confirmed in both organs.