Dietary zinc deficiency regulates the ROS/TLR4/NF-κB pathway to induce pancreatic inflammation and cell death in mice

Zinc (Zn) deficiency disrupts redox homeostasis in the body. The pancreas is a vital digestive and endocrine organ of the body, and its normal functional operation cannot proceed without the involvement of Zn. In this study, we established in vivo mouse models, including the normal Zn group (CG, 34 mg Zn/kg), Zn-deficient group (LZn, 2 mg Zn/kg), and Zn-supplemented group (HZn, 100 mg Zn/kg), as well as an in vitro Zn-deficient model of Mouse INsulinoma 6 (MIN6) cells. We systematically investigated the effects of Zn deficiency on pancreatic oxidative stress, inflammation, and cell death. The results showed that Zn deficiency significantly decreased the activities of α-amylase and lipase in the pancreas, and led to pancreatic histological damage. Through flow cytometry and detection of antioxidant enzyme activities, it was found that Zn deficiency induces excessive accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) in the pancreas, and inhibits antioxidant enzyme activities. Using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot, it was observed that Zn deficiency activates the TLR4/NF-κB pathway and significantly increases the expression of the NLRP3 inflammasome and inflammatory factors. Furthermore, Zn deficiency significantly upregulates the expression of apoptosis-related factors (Bax, Caspase-3, Caspase-7, Caspase-9) and necroptosis-related factors (RIPK1, RIPK3, MLKL). Treatment with the antioxidant N-acetylcysteine (NAC) reduces the level of ROS and inhibits the activation of the TLR4/NF-κB pathway, thereby alleviating Zn deficiency-induced inflammation and cell death. Taken together, Zn deficiency induces pancreatic inflammation and cell death by regulating the ROS/TLR4/NF-κB pathway.