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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.
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Objective:To evaluate the role of silencing regulatory protein (SIRT1) and its associated microRNAs (miRNAs) in dexmedetomidine-induced attenuation of renal damage in diabetic mice.Methods:SPF grade C57 male mice, aged 8 weeks, in which diabetes mellitus model was developed by intraperitoneal injection of 1% streptozotocin, were used.Thirty mice in which the model was successfully developed were divided into 5 groups ( n=6 each) using the random number table method: diabetes mellitus group (D group), diabetes mellitus + dexmedetomidine group (DD group), diabetes mellitus + dexmedetomidine + EX527 group (DDE group), diabetes mellitus + dexmedetomidine + miR-34a-3p-agomir group (DDH group), and diabetes mellitus + dexmedetomidine + miR-34a-3p-agomirNC group (DDC group). Six normal mice were selected as control group (C group). Dexmedetomidine 40 μg/kg was intraperitoneally injected once every 2 h, 3 times in total in DD, DDE, DDH and DDC groups.miR-34a-3p-agomir and miR-34a-3p-agomirNC 2.5 mmol were intraperitoneally injected via the tail vein at 72 h before dexmedetomidine administration once every 3 days, 2 times in total in DDH and DDC groups, respectively.SIRT1 inhibitor EX527 10 mg/kg was intraperitoneally injected at 1 h before dexmedetomidine administration in group DDE.At 24 h after the end of administration, serum concentrations of IL-6, IL-18, Cr and BUN, contents of nitric oxide (NO) and total antioxidant capacity (T-AOC), ROS activity, and expression of SIRT1, FoxO3a and P53 protein and mRNA, and expression of miR-217, miR-138 and miR-34a in renal tissues were determined. Results:Compared with group C, the serum IL-6, IL-18, Cr and BUN concentrations, contents of T-AOC and NO, and ROS activity were significantly increased, the expression of P53 protein and mRNA, miR-34a, miR-217 and miR-138 was up-regulated, and the expression of SIRT1 and FoxO3a protein and mRNA was down-regulated in group D ( P<0.05). Compared with group D, serum IL-6, IL-18, Cr and BUN concentrations, ROS activity and NO content were significantly decreased, T-AOC content was increased, the expression of SIRT1 and FoxO3a protein and mRNA was up-regulated, and the expression of miR-34a was down-regulated in group DD ( P<0.05). Compared with group DD, the serum IL-6, IL-18, Cr and BUN concentrations, NO content and ROS activity were significantly increased, T-AOC content was decreased, and the expression of SIRT1 and FoxO3a protein and mRNA was down-regulated in group DDE and group DDH ( P<0.05), no significant change was found in the expression of P53 protein and mRNA, miR-217, miR-34a and miR-138 in group DDE ( P>0.05), and the expression of P53 protein and mRNA and miR-34a was significantly up-regulated in group DDH ( P<0.05). Conclusions:The mechanism by which dexmedetomidine attenuates renal injury may be related to down-regulation of miR-34a expression, which further up-regulates SIRT1/FoxO3 expression and decreases oxidative stress in diabetic mice.
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Objective:To evaluate the effect of dexmedetomidine on pyroptosis in mice with acute renal injury induced by endotoxin and the relationship with miRNA-223-3p.Methods:Thirty-two clean-grade healthy male ICR mice, aged 8-12 weeks, weighing 20-25 g, were divided into 4 groups ( n=8 each) using the random number table method: control group (group C), lipopolysaccharide (LPS) group (group L), LPS plus dexmedetomidine group (group LD), and LPS plus dexmedetomidine plus atipamezole group (group LDT). The model of acute renal injury induced by endotoxin was established by intraperitoneal injection of LPS 400 μg/kg, followed by intraperitoneal injection of LPS 10 mg/kg 8 h later.Dexmedetomidine 40 μg/kg was intraperitoneally injected once every 2 h for 3 times in total starting from 30 min after establishing the model in group LD.Atipamezole 750 μg/kg was intraperitoneally injected immediately after establishing the model, and 30 min later dexmedetomidine 40 μg/kg was intraperitoneally injected once every 2 h for 3 times in total in group LDT.The equal volume of normal saline was intraperitoneally injected in group C. Blood samples were collected from the heart at 24 h after establishing the model, and serum creatinine (Cr) and blood urea nitrogen (BUN) concentrations were measured with an automatic biochemical analyzer.The animals were sacrificed and the left kidney tissues were obtained for microscopic examination of pathological changes after HE staining (with a light microscope) and for determination of the expression of caspase-1 p20, NOD-like receptor thermoprotein structural domain-related protein 3 (NLRP3) and ASC protein and mRNA (by quantitative real-time polymerase chain reaction and Western blot), contents of interleukin-1beta (IL-1β) and IL-18 (by enzyme-linked immunosorbent assay), and rate of pyroptosis in renal cortical cells (by TUNEL). Results:Compared with group C, the concentrations of serum Cr and BUN were significantly increased, the expression of NLRP3, caspase-1 p20 and ASC protein and mRNA in the renal tissues was up-regulated, the contents of IL-1β and IL-18 were increased, the rate of pyroptosis in renal cortical cells was increased ( P<0.05), no significant change was found in the expression of miRNA-223-3p ( P>0.05), and pathological changes of kidney were accentuated in group L. Compared with group L, the concentrations of serum Cr and BUN were significantly decreased, the expression of NLRP3, caspase-1 p20 and ASC protein and mRNA in the renal tissues was down-regulated, the contents of IL-1β and IL-18 were decreased, the rate of pyroptosis in renal cortical cells was decreased, the expression of miRNA-223-3p was up-regulated ( P<0.05), and pathological changes of kidney were attenuated in group LD.Compared with group LD, the concentrations of serum Cr and BUN were significantly increased, the contents of IL-1β and IL-18 were increased, the expression of NLRP3, caspase-1 p20 and ASC protein and mRNA in the renal tissues was up-regulated, the rate of pyroptosis in renal cortical cells was increased, the expression of miRNA-223-3p was down-regulated ( P<0.05), and the pathological changes of kidney were accentuated in group LDT. Conclusion:The mechanism by which dexmedetomidine reduces acute renal injury may be related to up-regulating the expression of miRNA-223-3p and inhibiting pyroptosis in mice.