Busulfan and cyclosphamide induce liver inflammation through NLRP3 activation in mice after hematopoietic stem cell transplantation

The aim of this study was to evaluate the role of NLRP3 inflammasome on BU/CY-induced liver inflammation in mice after HSCT. HSCT mice model was established through infusion of 5 x 10(6) bone marrow mononuclear cells after conditioned with BU/CY. On day 7, 14, 21 and 28 after HSCT, mice were sacrificed for analysis of liver inflammation, cytokine secretion, NLRP3 expression and caspase-1 activation as well as release of ATP and high-mobility group protein B1 (HMGB1). Furthermore, NLRP3 selective inhibitor (BAY 11-7082) was administrated into mice after HSCT to evaluate its effects on liver inflammation. Severe liver inflammation and damage with elevated secretion of IL-1 beta and IL-18 were found in mice after HSCT. Meanwhile, elevated expressions of NLRP3 and caspase-1 activation in liver were found. In addition, increased release of ATP and HMGB1 were observed. Selective inhibition of NLRP3 decreased caspase-1 activation and secretion of IL-1 beta and IL-18. Furthermore, NLRP3 inhibition also reduced infiltration of macrophages and neutrophils and improved liver function. In conclusion, NLRP3 was involved in BU/CY-induced liver inflammation after HSCT and selectively inhibited it ameliorated liver inflammation and improved liver function, suggesting targeting NLRP3 might be a new approach in the prophylaxis of liver inflammation after HSCT.