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Objective To evaluate the effects of sevoflurane postconditioning on mitophagy during myocardial ischemia-reperfusion (I/R) in rats.Methods Forty-two pathogen-free adult male SpragueDawley rats, weighing 250-300 g, were randomly divided into 3 groups (n=14 each) using a random number table: sham operation group (group S) , I/R group and sevoflurane postconditioning group (group SP).Myocardial I/R was induced by 30 min ligation of the left anterior descending branch of the coronary artery followed by 2 h of reperfusion.In group SP, 2.4％ sevoflurane was inhaled for 15 min starting from the onset of reperfusion, while 33％ oxygen was inhaled in group I/R.The rats were sacrificed at the end of reperfusion, and the hearts were removed for measurement of myocardial infarct size (by 1％ 2, 3, 5 triphenyltetrazolium chloride) , expression of LC3 Ⅱ/LC3 Ⅰ , Beclin-1, p62 and Parkin (by Western blot) ,and mitochondrial menbrane potential (by using JC-1 probe) , and for examination of the uhrastructure of cardiomyocytes (with transmission electron microscope).Results Compared with group S, the myocardial infarct size was significantly increased, mitochondrial membrane potential was decreased, the expression of LC3 Ⅱ/LC3 Ⅰ , Beclin-1 and Parkin was up-regulated, and the expression of p62 was down-regulated in group I/R.Compared with group I/R, the myocardial infarct size was significantly decreased, the mitochondrial membrane potential was increased, and the expression of LC3 Ⅱ/LC3 Ⅰ , Beclin-1, p62 and Parkin was down-regulated in group SP.Conclusion Sevoflurane postconditioning can mitigate I/R injury in rats, and inhibition of excessive activation of mitophagy may be involved in the nechanism.
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Objective To evaluate the effects of sevoflurane postconditioning on the expression of 70 kD aribosomalprotein S6 kinase (p70S6K) during ischemia-reperfusion (I/R) in isolated rat hearts.Methods Pathogen-free male Sprague-Dawley rats,aged 3 months,weighing 270-350 g,were used in the study.Their hearts were excised and perfused in a Langendorff apparatus with K-H solution saturated with 95 ％ O2-5 ％ CO2.Ninety isolated rat hearts with I/R injury were randomly divided into 3 groups (n =30 each):sham operation group (group S),I/R group (group I/R),and sevoflurane postconditioning group (group SP).The hearts were subjected to ischemia for 30 min followed by 2 h reperfusion.In group SP,the hearts were perfused with K-H solution saturated with 3.0％ sevoflurane for 15 min starting from the end of ischemia until 15 min of reperfusion,and then with plain K-H solution for 105 min.At 2 h of reperfusion,myocardial infarct size was measured,the percentage of myocardial infarct size was calculated,and the phosphorylated p70S6K (p-p70S6K)/total p70S6K (tp70S6K) ratio,and cytoplasm,cytochrome C,and caspase-8 expression was measured.Results Compared with group S,the percentage of myocardial infarct size and p-p70S6K/t-p70S6K ratio were significantly increased,the expression of cytochrome C,and caspase-8 was up-regulated,and the expression of cytochrome C was downregulated in I/R group.Compared with I/R group,the percentage of myocardial infarct size was significantly decreased,the ratio of p-p70S6K/t-p70S6K was increased and cytochrome C expression was up-regulated,and the expression of cytochrome C and caspase-8 was down-regulated in SP group.Conclusion Sevoflurane postconditioning can mitigate I/R injury to isolated rat hearts,and up-regulation of p-p70S6K expression,inhibition of transfer of cytochrome C from mitochondria to cytoplasm,and reduced cell apoptosis are involved in the mechanism.
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Objective To evaluate the effects of sevoflurane postconditioning on the oncosis and apoptosis in cardiomyocytes during ischemia-reperfusion (I/R) in isolated rat hearts and the role of extracellular signalregulated protein kinase 1/2 (ERK1/2) signal transduction pathway in it.Methods Seventy-two isolated rat hearts perfused in a Langendorff apparatus were randomly divided into 6 groups (n =12 each) using a random number table:sham operation group (group S),myocardial I/R group (group I/R),sevoflurane postconditioning group (group SP),PD98059 vehicle dimethyl sulfoxide (DMSO) group (group DMSO),selective ERK1/2 inhibitor PD98059 group (group PD),and sevoflurane postconditioning + PD98059 group (group SP + PD).The hearts were subjected to ischemia for 30 min followed by 2 h reperfusion in the other groups except group S.In SP,DMSO and PD groups,the hearts were perfused with K-H solution saturated with 3.0％ sevoflurane,DMSO (＜0.2％) and PD98059 (20 μmol/L),respectively,for 15 min starting from the end of ischemia until 15 min of reperfusion,and then with plain K-H solution for 105 min.In group SP+ PD,the hearts were perfused with K-H solution saturated with 3.0％ sevoflurane and PD98059 for 15 min starting from the end of ischemia until 15 min of reperfusion.Myocardial infarct size and expression of porimin and caspase-8 proteins (by Western blot) were measured at the end of reperfusion.Results Compared with S group,the myocardial infarct size was significantly increased,and the expression of porimin and caspase-8 proteins was up-regulated in the other groups (P ＜ 0.05).Compared with I/R group,the myocardial infarct size was significantly decreased,and the expression of porimin and caspase-8 proteins was down-regulated in group SP (P ＜ 0.05),and no significant changes were found in the other groups (P ＞ 0.05).Conclusion Sevoflurane postconditioning can activate ERK1/2 signal transduction pathway and inhibit the oncosis and apoptosis in cardiomyocytes,thus attenuating I/R injury in isolated rat hearts.
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Objective To evaluate the role of nitric oxide in sevoflurane postconditioning-induced mitigation of autophagy and cell apoptosis during ischemia/reperfusion (I/R) in isolated rat hearts.Methods The hearts of male Sprague-Dawley rats,aged 2-3 months,weighing 250-300 g,were excised and retrogradely perfused in a Langendorff apparatus.One hundred and eight isolated rat hearts,which were successfully perfused in a Langendorff apparatus,were equally and randomly divided into 6 groups:control group (C group),sevoflurane group (S group),I/R group,sevoflurane postconditioning group (SSP group),sevoflurane postconditioning + L-NAME (non-selective nitric oxide synthase (NOS) inhibitor group (SSP + L group),and L-NAME group (L group).The hearts were perfused with K-H solution for 150 min in C group.The hearts were continuously perfused for 180 min and perfused with K-H solution containing 3％ sevoflurane for 15 min starting from 60 min of perfusion in S group.After being perfused with K-H solution for 30 min,the hearts were subjected to occlusion for 30 min followed by reperfusion for 120 min in the other groups except C and S groups.After onset of reperfusion,the hearts were perfused with K-H solution containing 3％ sevoflurane for 15 min in SSP group,the hearts were perfused with K-H solution containing 3％ sevoflurane and L-NAME 100 μmol/L for 15 and 60 min,respectively,in SSP + L group,and the hearts were perfused with K-H solution containing L-NAME 100μmol/L for 60 min in L group.Inn ediately before ischemia,and at 30,60,90 and 120 min of reperfusion,each parameter of cardiac function was recorded.At the end of reperfusion,myocardial specimens were obtained at the end of reperfusion for measurement of the infarct size,NOS activity,NO content,and expression of Bcl-2,Beclin 1 and caspase-3,for observation of formation of autophagosomes,and for examination of the pathological changes.Results Compared with C group,LVSP,+ dp/dtmax,-dp/dtmax,NOS activity and NO content were significantly decreased,and LVEDP was increased in I/R and SSP groups.Compared with I/R group,LVSP,+ dp/dtmax,-dp/dtmax,NOS activity and NO content were significantly increased,LVEDP was decreased,Bcl-2 expression was down-regulated,and the expression of Beclin 1 and caspase-3 was up-regulated in SSP group,and no significant changes were found in each index in SSP+ L and L groups.Compared with SSP group,LVSP,+ dp/dtmax,-dp/dtmax,NOS activity and NO content were significantly decreased,LVEDP was increased,Bcl-2 expression was down-regulated,and the expression of Beclin 1 and caspase-3 was up-regulated in SSP + L group.Conclusion The mechanism by which sevoflurane postconditioning reduces I/R injury may be related to promoted NO product and inhibited autophagy and cell apoptosis in isolated rat hearts.
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Objective To evaluate the mechanism of external branch of the superior laryngeal nerve (EBSLN) injury during thyroid surgery as showed by intraoperative neuromonitoring.Methods 70 patients with 109 nerves at risk were enrolled in this study from March 2011 to October 2011.A positive signal is determined by observing contractions of the cricothyroid muscle.The relationship between EBSLN and the upper pole of the thyroid or the inferior constrictor muscle was studied.Results 108 nerves (99.1％) were located successfully,42 of which were visualized (38.9％).55 nerves (50.9％) crossed the superior thyroid artery more than 1 cm apart,while the other 53 nerves (49.1％) went less than 1 cm including 24 nerves(more than 0.5 cm,less than 1 cm) and 29 nerves (less than 0.5 cm) or coursed below the superior pole of the thyroid.The rate of the latter type was significantly elevated in patients with the top to botton diameter of the gland more than 5 cm.One patient suffered from impairing in the production of high tones postoperatively.Conclusions Intraoperative neuromonitoring is useful and helpful in providing instructive information for operations by locating EBSLN.
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Objective To investigate the effects of sevoflurane postconditioning on myocardial ischemiareperfusion (I/R)-induced oncosis of cardiomyocytes and the role of mitochondrial permeability transition pore (MPTP) in it.Methods Sixty male Sprague-Dawley rats,aged 3 months,weighing 280-360 g,were randomly divided into 5 groups (n =12 each):sham operation group (group S),group I/R,sevoflurane postconditioning group (group SP),sevoflurane postconditioning + atractyloside group (group SP + ATR) and atractyloside group (group ATR).Myocardial ischemia was induced by 30 min occlusion of left anterior descending branch (LAD) of coronary artery followed by 2 h reperfusion.2.5 ％ sevoflurane was inhaled for 5 min starting from 27 min of ischemia until 2 min after beginning of reperfusion in SP and SP + ATR groups,while 33 ％ oxygen was inhaled in the other groups.In SP + ATR and ATR groups,atractyloside 5 mg/kg was injected via the internal jugular vein at 15 min before ischemia.HR and systolic pressure were monitored and recorded and rate-pressure product (RPP) was calculated.At the end of reperfusion,the rats were sacrificed and the hearts removed for determination of myocardial infarct size.The myocardial ultrastrncture was observed by electron microscopy.The expression of Porimin (Pro-oncosis receptor inducing membrane injury) was measured by Western blot.Myocardial nicotinamide adenine dinucleotide (NAD+) content was determined by spectrophotometry.Results Compared with group S,the myocardial infarct size was significantly enlarged,the expression of Porimin was up-regulated,and NAD+ content and RPP were decreased in the other four groups (P ＜ 0.05).Compared with groups I/R and SP + ATR,the infarct size was significantly decreased,the expression of Porimin was down-regulated,and NAD+ content was increased in group SP (P ＜ 0.05),and no significant change was found in the indices mentioned above in group ATR (P ＞0.05).Conclusion Sevoflurane postconditioning can mitigate myocardial I/R injury by inhibiting MPTP opening and reducing oncosis of cardiomyocytes.
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Objective To evaluate the role of the mitochondrial ATP-sensitive potassium (mito-KATP)channel in sevoflurane preconditioning-induced delayed cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts.Methods Seventy-two adult male Sprague-Dawley rats were randomly divided into 6 groups (n =12 each):control group (group CON),I/R group,sevoflurane control group (group SEVO),sevoflurane preconditioning group (group SWO P),5-hydroxydeconoate (5-HD) + sevoflurane preconditioning group (group 5-HD+ SWOP) and 5-HD control group (group 5-HD).The rats were exposed to 33％ pure oxygen for 1 h in groups CON and I/R.The rats were exposed to 2.5％ sevoflurane for 1 h in groups SEVO and SWOP.5-HD (a mito-KATP channel inhibitor) 10 mg/kg was injected intraperitoneally 30 min before sevoflurane preconditioning in group 5-HD + SWOP.5-HD 10 mg/kg was injected intraperitoneally in group 5-HD.The hearts were immediately removed and perfused in a Langendorff apparatus.The hearts were made globally ischemic for 30 min followed by 120 min reperfusion in groups I/R,SWOP,5-HD + SWOP and 5-HD.The expression of phosphorylated protein kinase C-epsilon (p-PKC-ε) and caspase-8 was measured by Western blot immediately before ischemia (T0) and at 120 min of reperfusion (T1).The myocardial infarct volume was measured by TTC staining.Results Compared with group CON,the myocardial infarct volume was significantly increased at T1 in groups I/R,SWOP,5-HD +SWOP and 5-HD,p-PKC-ε expression was up-regulated at T0 in groups SEVO and SWOP and at T1 in groups I/R,SWOP,5-HD + SWOP and 5-HD,and caspase-8 expression was down-regulated at T1 in group SEVO (P ＜0.05).Compared with group I/R,the myocardial infarct volume was significantly decreased at T1 in groups SWOP and 5-HD + SWOP,p-PKC-ε expression was up-regulated at T0 in groups SEVO and SWOP,and caspase-8 expression was down-regulated at T1 in group SWOP (P ＜ 0.05).Compared with group SWOP,the myocardial infarct volume was significantly increased,p-PKC-ε expression was down-regulated at T0,and caspase-8 expression was up-regulated at T1 in group 5-HD + SWOP (P ＜ 0.05).Conclusion The mito-KATP channel is involved in sevoflurane preconditioning-induced delayed cardioprotection against I/R injury in isolated rat hearts through upregulation of p-PKC-ε expression before ischemia and inhibition of cell apoptosis during reperfusion.