Role of NLRP3 Inflammasome in Hepatic Veno-Occlusive Disease After Allogeneic Hematopoietic Stem Cell Transplantation Undergoing Different Pre-Treatments

Abstract

Objective To study the role of NOD-like domain (NLRP)3 inflammasome in hepatic venoocclusive disease (HVOD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) undergoing different pre-treatments.Methods A total of 50 specific-pathogen free (SPF) male BALB/c (H 2Kd) mice were included in this study,and randomly divided into study group (n=40) and control group (n=10) by computer.According to the differences of allo-HSCT pre-treatment programs,study group mice were divided into two groups:busulfan/cyclophosphamide (BU/CY) pre-treatment group (n =20) and total body irradiation (TBI) pre-treatment group (n=20).The experiment was disposed with the ethical standard.On the 15th day after allo-HSCT,recipient mice in each group were sacrificed and collected bone marrow and whole liver samples,in order to detect the chimeric rate and white blood cell (WBC) count,and calculate liver index.The liver samples were divided into two parts.One part of liver samples were observed the histologic pathology by hematoxylin-eosin (HE) staining,Masson's trichrome staining and immunohistochemistry,and gave pathological score of HVOD to evaluate the degree of liver injury.Another part of liver samples were assessed relative expression levels of cytokine interleukin (IL)-1β,-18 by realtime fluorescence quantitative polymerase chain reaction (PCR) to study the role of inflammatory injury to HVOD.Then,liver samples were assessed relative expression levels of cysteine aspartic proteases (Caspase)-1 and NLRP3 to study role of NLRP3 in HVOD after allo-HSCT undergoing different pretreatments.Results ① Hematopoietic stem cells had been successfully transplanted into study group mice with chimeric rate over 98.0％ on the 15th day after allo-HSCT.② The pathology injury of HVOD in BU/CY pre-treatment group was more than that of TBI pre-treatment group.In BU/CY pre-treatment transplantation group,liver index was below and 10 cases of HVOD samples were diagnosed severe HVOD;while in TBI pre-treatment group,5 cases of HVOD samples were diagnosed as medium HVOD and another 5 cases were diagnosed as severe HVOD.③ The relative expression levels of IL-1β,-18 in BU/CY pretreatment group were 13.9 times and 5.5 times of that in TBI pre-treatment group,so the inflammatory injury of BU/CY pre-treatment group was more serious than that of TBI pre-treatment group,and there were statistical differences between two groups (P＜0.05).④ Relative expression level of caspase-1 in BU/CY pre-treatment group was 19.5 times of that in TBI pre-treatment group,the relative expression level of NLRP3 in BU/CY pre-treatment group was 1.2 times of that in TBI pre-treatment group,and there was statistical difference between two groups (P＜0.05).Conclusions Thc relative expression level of NLRP3 in BU/CY pre-treatment group was more than that of TBI pre-treatment group,which accorded with the degree of liver injury.NLRP3 inflammasome played an important role in HVOD after allo-HSCT. Key words: NLRP3 protein, human; Cytokine; Busulfan; Cyclophosphamide; Total-body irradiation; Hepatic veno-occlusive disease