When AP occurs, the oxidation and antioxidant systems are unbalanced, resulting in the production and accumulation of a large amount of ROS in the cell, which in turn lead to the production of lipid peroxides . Ferroptosis underscores the importance of iron ions to ROS. In our study, compared to that in the control group, the iron content in the AP group increased, GSH decreased, and lipid peroxide increased significantly. After the application of divalent iron chelating agents, there was a significant improvement in these parameters (Fig. 1). Therefore, we believe that in the process of AP, an imbalance of oxidative stress caused by iron ion aggregation, the production of lipid peroxides, and ferroptosis are present. Through inhibition of the occurrence of ferroptosis, pancreatic damage during AP can be effectively alleviated (Fig. 5).
GPX4 plays a pivotal role in the occurrence of ferroptosis and is a key regulator. GPX4 converts GSH into oxidized glutathione and reduces cytotoxic lipid peroxides to the corresponding alcohols [3, 6]. Inside the cell, ferritin can serve as a reservoir of iron ions. When Fe2+ aggregates within cells, it is transported and stored in unstable iron pools and ferritin. Abnormal iron metabolic processes can trigger disturbances in intracellular function, prompting further ferroptosis . Our study found that GPX4 and expression in the AP group were higher than those in the control group (Fig. 2A, 2C). Elevated GPX4 expression in AP improves the antioxidant capacity of tissue cells. However, due to the lack of its substrate GSH, the total antioxidant capacity remains unassailable. In addition, ferritin was higher in the AP group than in the control group, and the increase in ferritin content was positively correlated with the increase in iron ions (Fig. 2B). This finding is consistent with the fact that Fe2+ can be stored in ferritin when it aggregates within cells. The expression of GPX4 and ferritin following application of 2, 2'-bipyridyl decreased to a certain extent compared with that in the AP group.
The NLRP3 pathway has led to progress in the study of AP . There is growing evidence that the inflammatory response is also activated when ferroptosis occurs. In this study, we found that the expression of NLRP3 decreased significantly in the AP + 2, 2'-bipyridyl group compared with the AP group (Fig. 3, 4). Its downstream pathway caspase-1/IL-1β/TNF-α was also significantly different from that in the AP group. Our experiments confirmed that iron ion aggregation can regulate the occurrence and development of AP through the NLRP3 pathway. Inhibiting iron ions can effectively reduce the severity of AP.