[Effect of zinc oxide nanoparticles on hypoxia and pyroptosis of rat neutrophils].

Objective: To investigate the effects of zinc oxide nanoparticles (ZnO-NPs) on neutrophil hypoxia and pyroptosis through nucleotide binding of oligomeric domain-like receptor protein 3 (NLRP3) inflammasome, and to analyze the role of pyroptosis on respiratory tract inflammotion induced by ZnO-NPs. Methods: In October 2022, primary cultured neutrophils were obtained from the abdominal aortic blood of SPF adult healthy SD rats. The neutrophils were treated with ZnO-NPs solution (0, 5, 10, 20 μg/ml) at different concentrations, and hypoxia group (5% O(2)) was set up. Hypoxia and reactive oxygen species (ROS) levels were detected by flow cytometry, and the expression levels of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), cleaved Caspase-1 were measured by Western blot. The activity of lactic dehydrogenase (LDH) in the cell supernatant was measured by coloration, and the content of interleukin-1 beta (IL-1β) in cell culture supernatant was detected by enzyme-linked immunosorbent assay (ELISA) . Results: Compared with the control group, hypoxia and ROS levels of neutrophils in hypoxia group and ZnO-NPs groups were significantly increased (P<0.05), and NLRP3, ASC, cleaved Caspase-1 protein expression levels, LDH activity and IL-1β content were significantly increased (P<0.05). Compared with hypoxia group, hypoxia and ROS levels of neutrophils in 5 μg/ml and 10 μg/ml ZnO-NPs groups were significantly decreased (P<0.05), NLRP3, ASC, cleaved Caspase-1 protein expression levels, LDH activity, and IL-1β content were decreased significantly (P<0.05). There were no significant differences in hypoxia, ROS levels, ASC, cleaved Caspase-1 protein expression levels, LDH activity, and IL-1β content between the 20 μg/ml ZnO-NPs group and the hypoxia group (P>0.05) . Conclusion: ZnO-NPs treatment may activate the NLRP3 inflammasome to induce pyroptosis of neutrophils which may be related to ROS and hypoxia.