Study on the Protective Mechanism of Dihydromyricetin Against Aflatoxin B1-Induced Injury in Madin–Darby Canine Kidney Cells

Aflatoxin B₁ (AFB₁) is a common contaminant in canine diets that can cause significant damage to metabolic organs with prolonged exposure. Dihydromyricetin (DMY), a flavonoid compound abundant in <i>Ampelopsis grossedentata</i>, is widely used in functional foods due to its diverse biological activities. This study aimed to investigate the mechanism by which DMY alleviates AFB1-induced damage in MDCK cells. Four experimental groups were established: a control group with culture medium only (CON group), a group treated with 5 μg/mL AFB1 (AFB1 group), and two treatment groups treated with 5 μg/mL AFB1 combined with either 25 mmol/L or 50 mmol/L DMY-concentrations with more robust and stable protective effects than 100 mmol/L DMY, as confirmed by experimental screening. The results showed that AFB₁ significantly reduced MDCK cell viability at concentrations of 5-30 μg/mL (<i>p</i> < 0.01), while DMY at 25-100 mmol/L markedly improved cell viability (<i>p</i> < 0.01). AFB₁ treatment led to a significant increase in reactive oxygen species (ROS), malondialdehyde (MDA), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) levels, along with a reduction in superoxide dismutase (SOD) and catalase (CAT) activities (<i>p</i> < 0.01). 25 mmol/L and 50 mmol/L DMY treatment reversed these effects, decreasing ROS, MDA, TNF-α, IL-6, and IL-1β levels while increasing SOD and CAT activities (<i>p</i> < 0.01). Furthermore, 25 mmol/L and 50 mmol/L DMY improved mitochondrial membrane potential (<i>p</i> < 0.01), counteracting AFB₁'s inhibitory effects on autophagy-related proteins by promoting p-AMPK and Beclin-1 expression while inhibiting p-mTOR, p53, and p62 expression (<i>p</i> < 0.05). In conclusion, DMY mitigates AFB₁-induced damage in MDCK cells by enhancing anti-inflammatory and antioxidant defenses and promoting autophagy, providing a theoretical foundation for future treatment strategies for canine kidney damage.