ABSTRACT
Objective:To evaluate the role of hypoxia-inducible factor-1α (HIF-1α)/Bcl-2/E1B 19-kDa interacting protein 3 (BNIP3) signaling pathway in dexmedetomidine-induced reduction of myocardial ischemia-reperfusion (I/R)-induced brain injury in mice.Methods:Sixty clean-grade healthy male C57BL/6 mice, aged 8-10 weeks, weighting 20-30 g, were divided into 5 groups ( n=12 each) using a random number table method: sham operation group (S group), myocardial I/R group (IR group), myocardial I/R plus dexmedetomidine group (IRD group), myocardial I/R plus HIF-1α inhibitor 2ME2 group (IR-M group), and myocardial I/R plus dexmedetomidine plus HIF-1α inhibitor 2ME2 group (IRD-M group). The myocardial I/R-induced brain injury was produced by ligating the left anterior descending coronary artery for 30 min followed by 2 h of reperfusion in anesthetized mice.Dexmedetomidine 50 μg/kg was intraperitoneally injected at 5 min before ischemia in IRD group and IRD-M group.In IR-M and IRD-M groups, 2ME2 15 mg/kg was intraperitoneally injected at 5 min before ischemia.Blood samples were collected from the thoracic aorta at 2 h of reperfusion to measure the serum S-100β protein and neuron-specific enolase (NSE) concentrations.The animals were then sacrificed, brains were removed and hippocampi were obtained for determination of the apoptosis index (by TUNEL method) and expression of HIF-1α, BNIP3, Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) and phosphorylated Tau protein (p-Tau) (by Western blot) and for microscopic examination of the pathological changes in hippocampal CA1 region.LC3Ⅱ/Ⅰ ratio was calculated. Results:Compared with group S, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of HIF-1α, BNIP3, Beclin-1 and p-Tau was up-regulated, LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in group IR.Compared with group IR, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly decreased, the expression of HIF-1α, BNIP3 and Beclin-1 was up-regulated, the expression of p-Tau was down-regulated, and LC3Ⅱ/Ⅰ ratio was increased ( P<0.05), and the pathological changes in hippocampal CA1 region were significantly attenuated in group IRD.Compared with group IRD, the concentrations of serum S-100β protein and NSE and apoptosis index of hippocampal neurons were significantly increased, the expression of p-Tau was up-regulated, the expression of HIF-1α, BNIP3 and Beclin-1 was down-regulated, LC3Ⅱ/Ⅰ ratio was decreased ( P<0.05), and the pathological changes in hippocampal CA1 region were aggravated in IR-M and IRD-M groups. Conclusions:HIF-1α/BNIP3 signaling pathway is involved in dexmedetomidine-induced reduction of myocardial I/R-induced brain injury in mice.
ABSTRACT
Objective:To evaluate the role of hypoxia-inducible factor-1α (HIF-1α)/Bcl-2/E1B-19kDa interacting protein 3 (BNIP3) signaling pathway in sevoflurane-induced attenuation of myocardial ischemia-reperfusion (I/R) injury in rats and the relationship with autophagy.Methods:Ninety healthy adult male Sprague-Dawley rats, weighing 300-350 g, were randomly divided into 5 groups ( n=18 each): sham operation group (Sham group), I/R group, sevoflurane group (SEV group), HIF-1a inhibitor 2ME2 group (2ME2 group), and 2ME2+ sevoflurane group (MSP group). Myocardial I/R injury model was established by ligating the left anterior descending branch of coronary artery for 40 min followed by 120-min reperfusion in anesthetized rats.In SEV group, 2.4% sevoflurane was inhaled for 15 min starting from the beginning of reperfusion.In 2ME2 group and MSP group, 2ME2 (15 mg/kg) was intraperitoneally injected at 1 h before ligation of the left anterior descending branch of coronary artery, and the other treatments were similar to those previously described in group I/R or in group SEV.Animals were sacrificed at 120 min of reperfusion, and the left ventricular myocardium was taken for determination of the expression of HIF-1α and BNIP3 (by Western blot), activity of ROS (by DHE), and myocardial infarct size (by TTC)and for observation of autophagosome (with an electron microscope). Results:Compared with Sham group, the activity of ROS, the number of autophagosome and myocardial infarct size were significantly increased in the other four groups, the expression of HIF-1α and BNIP3 was up-regulated in I/R group and SEV group ( P<0.05). Compared with I/R group, the activity of ROS, the number of autophagosome and myocardial infarct size were significantly decreased in the other four groups, the expression of HIF-1α and BNIP3 was up-regulated in SEV group, and no significant difference was found in the activity of ROS, the number of autophagosome or myocardial infarct size ( P>0.05), and the expression of HIF-1α and BNIP3 was down-regulated in 2ME2 and MSP groups ( P<0.05). Compared with SEV group, the activity of ROS, the number of autophagosome and myocardial infarct size were significantly increased, and the expression of HIF-1α and BNIP3 was down-regulated in 2ME2 and MSP groups ( P<0.05). Conclusion:HIF-1α/BNIP3 signaling pathway is involved in sevoflurane-induced attenuation of myocardial I/R injury, which is related to inhibiting autophagy in rats.
ABSTRACT
Objective To evaluate the role of Janus kinase 2-signal transducer and activator of transcription 3 (JAK2-STAT3) signaling pathway in sevoflurane postconditioning-induced inhibition of mitochondrial permeability transition pore (mPTP) opening during myocardial ischemia-reperfusion (I/R)in rats.Methods Sixty pathogen-free healthy male Sprague-Dawley rats,weighing 250-300 g,were divided into 4 groups (n=15 each) using a random number table:I/R group,sevoflurane postconditioning group (group SP),AG-490 group (group AG) and sevoflurane postconditioning plus AG-490 group (group SP+AG).Myocardial I/R was induced by 30 min ligation of the left anterior descending branch of coronary artery followed by 120 min reperfusion.In group SP,2.8％ sevoflurane was inhaled for 15 min starting from 2 min before reperfusion.JAK2 inhibitor AG-490 3 mg/kg was intravenously injected at 10 min before reperfusion in group AG.In group SP+AG,AG-490 3 mg/kg was intravenously injected at 10 min before reperfusion,and 2.8％ sevoflurane was inhaled for 15 min starting from 2 min before reperfusion.At 15 min of reperfusion,5 rats were sacrificed and myocardial specimens were obtained for determination of the expression of JAK2,phosphorylated JAK2 (p-JAK2),STAT3 and phosphorylated STAT3 (p-STAT3)in myocardial tissues by Western blot.The ratios of p-JAK2 to JAK2 expression (p-JAK2/JAK2) and pSTAT3 to STAT3 expression (p-STAT3/STAT3) were calculated.Five rats were sacrificed at the end of reperfusion for measurement of myocardial infarct size.The left 5 rats were selected and sacrificed,myocardial specimens were obtained,and the opening of mPTP was detected by a calcein-cobalt quenching method.Results Compared with group I/R,the myocardial infarct size and mPTP opening were significantly decreased,and JAK2/p-JAK2 and STAT3/p-STAT3 were increased in group SP (P＜0.05),and no significant change was found in the parameters mentioned above in SP+AG and AG groups (P＞0.05).Compared with group SP,the myocardial infarct size was significantly enlarged,the extent of mnPTP opening was aggravated,and JAK2/p-JAK2 and STAT3/p-STAT3 were decreased in SP+AG and AG groups (P＜0.05).Conclusion The mechanism by which sevoflurane postconditioning inhibits the opening of mPTP during myocardial I/R is related to activation of JAK2-STAT3 signaling pathway in rats.
ABSTRACT
Objective To evaluate the effect of sevoflurane postconditioning on microRNA-133a (miR-133a) expression during myocardial ischemia-reperfusion (I/R) in mice.Methods Thirty adult male C57 mice,weighing 20-30 g,were randomized to 3 groups (n =10 each) using a random number table:control group (group C),I/R group,and sevoflurane postconditioning group (group SP).In I/R and SP groups,hearts from adult male C57 mice were exposed and subjected to 30 min of ischemia and 180 min of reperfusion in anesthetized mice according to the method described by Das et al.In group C,only thoracotomy was performed without ligation of the coronary artery.In group SP,2.4％ sevoflurane was inhaled for 5 min starting from the onset of reperfusion to perform sevoflurane postconditioning.At 180 min of reperfusion,blood samples from the femoral vein were collected for determination of serum lactic dehydrogenase (LDH) and creatine kinase (CK) activities using the colorimetric method.The mice were then sacrificed,and myocardial specimens were obtained for determination of myocardial infarct size,miR133a and caspase-9 mRNA expression (by real-time reverse transcriptase polymerase chain reaction),and caspase-9 expression (by Western blot).Results Compared with group C,the serum LDH and CK activities and myocardial infarct size were significantly increased in I/R and SP groups,the expression of miR-133a was significantly down-regulated,and the expression of caspase-9 protein and mRNA was significantly up-regulated in group I/R,and the expression of miR-133a and caspase-9 protein and mRNA was significantly up-regulated in group SP (P＜0.05).Compared with group I/R,the serum LDH and.CK activities and myocardial infarct size were significantly decreased,the expression of miR-133a was significantly up-regulated,and the expression of caspase-9 protein and mRNA was significantly downregulated in group SP (P＜0.05).Conclusion The mechanism by which sevoflurane postconditioning inhibits cell apoptosis during myocardial I/R is related to up-regulation of miR-133a expression in mice.