Dexmedetomidine Inhibits Parthanatos in Cardiomyocytes and in Aortic Banded Mice by the ROS-Mediated NLRP3 Inflammasome Activation.

Dexmedetomidine (DEX) is clinically used for sedation of patients in intensive care, which also has been shown to have a strong anti-inflammatory effect on a variety of diseases. Parthanatos is a newly discovered form of programmed cell death. Here, we aimed to explore whether DEX protects cardiomyocytes from parthanatos in chronic heart failure (CHF). The levels of malondialdehyde (MAD), total superoxide dismutase (SOD), and adenosine triphosphate (ATP) were measured by corresponding detection kits. CHF mice model was established by transverse aortic constriction (TAC). PARP-1 expression in cardiac tissues of wild-type CHF mice was evaluated by immunohistochemistry. Flow cytometry was used to detect the effect of N-methyl-N'-nitro-N'-nitrosoguanidine (MNNG) on cell death. Masson trichrome staining and hematoxylin and eosin staining were conducted in cardiac tissues to evaluate the histological changes. TUNEL and caspase-1 double-staining and caspase-1 and NLRP3 double-staining were conducted in cardiac tissues to evaluate the effect of DEX on cell death in vivo. The relative expression of parthanatos and NLRP3 inflammasome-related proteins was evaluated by western blotting. MNNG induced parthanatos in mouse HL-1 cardiomyocytes. MNNG-induced parthanatos was promoted by ROS production and NLRP3 inflammasome activation. DEX treatment suppressed MNNG-induced parthanatos via NLRP3 inflammasome activation mediated by ROS. Importantly, DEX inhibited pathological changes and parthanatos in CHF mice. DEX suppressed the ROS/NLRP3 signaling pathway in CHF mice. DEX inhibited parthanatos in cardiomyocytes and in CHF mice by regulating the ROS-mediated NLRP3 inflammasome activation. The PARP-1 activation and NLRP3 inflammasome activation induced by MNNG was inhibited by DEX treatment, thus the generation of ROS was further inhibited, suggesting the inhibitory effect of DEX treatment on parthanatos in cardiomyocytes.