Relationship between Sestrin2 and mtDNA-NLRP3 inflammasome pathway during endotoxin-induced myocardial injury in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between Sestrin2 and mitochondrial DNA (mtDNA)-NOD-like receptor associated protein 3 (NLRP3) inflammasome pathway during endotoxin-induced myocardial injury in mice.Methods:One hundred and eighty-four clean-grade healthy male ICR mice, aged 8-12 weeks, weighing 20-25 g, were used in this study. One hundred and sixty-eight mice were divided into 7 groups ( n=24 each) using the random number table method: normal control group (N group), lipopolysaccaride(LPS) group (L group), mtDNA group, LPS+ mtDNA group (M group), normal control+ negative control adeno-associated virus (AAV-NC)group (NC group), LPS+ mtDNA+ AAV-NC group (MC group), and LPS+ mtDNA+ Sestrin2 overexpression adeno-associated virus (AAV-Sestrin2) group (MSgroup). Another 10 mice were used to detect the transfection effect of AAV-Sestrin2, and the left 6 mice were used for mtDNA extraction. The model of endotoxemia was developed by intraperitoneal injection of LPS 10 mg/kg. mtDNA 5 mg/kg was intraperitoneally injected in mtDNA group, and mtDNA 5 mg/kg was intraperitoneally injected at 30 min after LPS injection in M group.AAV-Sestrin2 150 μl was injected via the tail vein in MS group, and the equal volume of AAV-NC was injected via the tail vein in MC and NC groups. Four weeks after virus injection, LPS 10 mg/kg was intraperitoneally injected and 30 min later mtDNA 5 mg/kg was intraperitoneally injected in MS and MC groups. Blood samples were collected at 24 h after LPS injection for determination of serum creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) activities (by biochemical assay), concentrations of serum cardiac troponin I (cTnI), interleukin-18 (IL-18) and interleukin-1beta (IL-1β)(by enzyme-linked immunesorbent assay), and expression of mtDNA (by quantitative real-time polymerase chain reaction). The animals were sacrificed after the end of blood sampling and myocardial tissues were obtained for determination of the contents of reactive oxygen species (ROS), total antioxidant capacity (T-AOC), and adenosine triphosphate (ATP) and expression of NOD-like receptor associated protein 3 (NLRP3), active subunit p20 of caspase-1 (caspase-1p20) and apoptosis-associated microprotein (ASC) in myocardial tissues (by Western blot) and for microscopic examination of the pathological changes after HE staining (with a light microscope). Results:Compared with N group, the levels of CK-MB, LDH, cTnI, IL-1β and IL-18 in serum were significantly increased, the expression of mtDNA was up-regulated, the ROS content in myocardial tissues was increased, the T-AOC and ATP contents in myocardial tissues were decreased, the expression of NLRP3, caspase-1p20 and ASC in the myocardial tissues was up-regulated( P<0.05), and the pathological changes of myocardial tissues were aggravated in L group and mtDNA group.Compared with L group and mtDNA group, the levels of CK-MB, LDH, cTnI, IL-1β and IL-18 in serum were significantly increased, the expression of mtDNA was up-regulated, the ROS content in myocardial tissues was increased, the T-AOC and ATP contents in myocardial tissues were decreased, the expression of NLRP3, caspase-1p20 and ASC in the myocardial tissues was up-regulated( P<0.05), and the pathological changes of myocardial tissues were aggravated in M group. Compared with M group, the levels of CK-MB, LDH, cTnI, IL-1β and IL-18 in serum were significantly decreased, the expression of mtDNA was down-regulated, the ROS content in myocardial tissues was decreased, the T-AOC and ATP contents in myocardial tissues were increased, the expression of NLRP3, caspase-1p20 and ASC in the myocardial tissues was down-regulated( P<0.05), and the pathological changes of myocardial tissues were significantly attenuated in MS group. Conclusions:Sestrin2 can reduce endotoxin-induced myocardial injury in mice by alleviating mitochondrial damage, inhibiting oxidative stress, protecting mtDNA from oxidative damage, and then inhibiting mtDNA-NLRP3 inflammasome pathway.