Protective effects of NLRP3 inhibitor MCC950 on sepsis-induced myocardial dysfunction

Sepsis-induced myocardial dysfunction (SIMD) leads to poor prognosis or even death in severe sepsis cases, therefore, exploring its pathogenesis and new therapeutic targets has become the focus of current research. Specifically, an SIMD rat model was constructed by cecal ligation and puncture (CLP) method. At 24 h after intraperitoneal injection of the NLRP3 selective inhibitor MCC950, the levels of serum cardiac troponin I (cTnI) and Lactate dehydrogenase (LDH) in serum were detected, and the cardiac function of rats was examined via echocardiography. In addition, the pathological changes of myocardial tissues were observed by histological method, and the expression changes of inflammatory factors were detected in the tissue and serum. At the same time, H9C2 cells were treated with lipopolysaccharide (LPS) to simulate the in vitro model, and the expressions of inflammation and pyroptosis-related factors were detected. The results manifested that in the CLP group, the levels of serum cTnI and LDH were obviously increased, the myocardial tissue structure was disordered, the cell edema was severe, and the cardiac function was markedly reduced. Meanwhile, the expressions of inflammatory factors IL-6, IL-8 and TNF-α rose remarkably. On the contrary, MCC950 effectively reversed the above situation. Moreover, MCC950 inhibited LPS-induced inflammation and pyroptosis of H9C2 cells. In conclusion, the NLRP3 inhibitor MCC950 can reduce the release of LDH and other cellular inflammatory factors in the cytoplasm, thereby improving the cardiac function and slowing down the apoptosis of cardiomyocytes, which may be related to the inhibition of NLRP3/Caspase-1/IL-1β pathway.