Inhibiting ferroptosis attenuates myocardial injury in septic mice: the role of lipocalin-2 / 南方医科大学学报

OBJECTIVE@#To explore the contribution of ferroptosis to myocardial injury in mouse models of sepsis and the role lipocalin-2 (Lcn2) in ferroptosis.@*METHODS@#Adult male C57BL/6 mice were randomized equally into sham-operated group, cecal ligation and puncture (CLP)-induced sepsis group, and CLP + Fer-1 group where the mice received intraperitoneal injection of 5 mg/mL Fer-1 (5 mg/kg) 1 h before CLP. The left ventricular functions (including LVEF%, LVFS%, LVIDd and LVIDs) of the mice were assessed by echocardiography at 24 h after CLP. Myocardial injury in the mice was observed with HE staining, and the changes of myocardial ultrastructure and mitochondria were observed using transmission electron microscopy (TEM). Serum TNF-α level was measured with ELISA, and the changes of myocardial iron content were detected using tissue iron kit. The protein expressions of myocardial Lcn2, glutathione peroxidase 4 (GPX4) and ferroptosis suppressor protein 1 (FSP1) were determined with Western blotting.@*RESULTS@#The septic mice showed significantly decreased LVEF%, LVFS% and LVIDd and increased LVIDs at 24 h after CLP (P < 0.05), and these changes were significantly improved by Fer-1 treatment. Sepsis caused obvious myocardial pathologies and changes in myocardial ultrastructure and mitochondria, which were significantly improved by Fer-1 treatment. Fer-1 treatment also significantly ameliorated sepsis-induced elevations of serum TNF-α level, myocardial tissue iron content, and Lcn2 protein expression and the reduction of GPX4 and FSP1 protein expression levels (P < 0.05).@*CONCLUSION@#GPX4- and FSP1-mediated ferroptosis are involved in myocardial injury in mice with CLP-induced sepsis, and inhibition of ferroptosis can attenuate septic myocardial injury, in which Lcn2 may play a role.

Effects of high glucose induced primary cardiomyocytes injury on necroptosis and the related mechanism / 中国应用生理学杂志

OBJECTIVE@#To observe whether necroptosis was happened in high glucose (HG) - induced primary cardiomyocytes injury and to investigate the likely mechanism.@*METHODS@#The primary cultured cardiomyocytes were divided into 4 groups (n=9): control group (the cardiomyocytes were incubated with 5.5 mmol/L glucose for 48 h), HG group (the cardiomyocytes were incubated with 30 mmol/L glucose for 48 h), HG + necrostatin-1 (Nec-1) group (the cardiomyocytes was co-incubated with necroptosis inhibitor Nec-1 at 100 μmol/L and HG for 48 h) and hypertonic pressure group (HPG, the cardiomyocytes was co-incubated with 5.5 mmol/L glucose and 24.5 mmol/L mannitol for 48 h). Cell viability was measured by MTT method, reactive oxygen species (ROS) generation was measured by DHE staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were tested by ELISA method. The mRNA and protein expressions of necroptosis related genes receptor interacting serine/threonine protein kinase 1 (RIP1), RIP3, mixed lineage kinase domain-like protein (MLKL) were tested by quantitative real-time PCR and Western blot.@*RESULTS@#The results showed HG intervention decreased cardiomyocytes viability, increased ROS generation, up-regulated the levels of TNF-α, IL-6 and IL-1β, increased RIP1, RIP3, MLKL expressions at mRNA and protein levels. Nec-1 treatment attenuated HG-induced increased cardiomyocytes viability, reduced ROS generation, down-regulated the levels of TNF-α, IL-6 and IL-1β, decreased RIP1, RIP3, MLKL expressions at mRNA and protein levels.@*CONCLUSION@#Necroptosis was happened in high glucose-induced primary cardiomyocytes injury. Inhibition of necroptosis can reduce high glucose-induced cardiomyocytes damage, may be related to inhibition of oxidative stress and depression of inflammative factors releasing.

Role of mitochondrial permeability transition pore in mediating the effect of endomorphin-1 postconditioning against myocardial ischemia-reperfusion injury in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of mitochondrial permeability transition pore (MPTP) opening in mediating the effect of endomorphine-1 postconditioning to alleviate myocardial ischemia-reperfusion (IR) injury in rats.</p><p><b>METHODS</b>Forty-five male SD rats were randomized equally for sham operation, myocardial IR injury, endomorphin-1 postconditioning, atractyloside (a MPTP opener) postconditioning, or endomorphin-1 + atractyloside postconditioning. The hemodynamic param-eters of the rats were monitored in real time via carotid artery cannulation to the left ventricle. After reperfusion, plasma samples were collected for biochemical analyses. The size of myocardial infarct area was detected using Evans blue and TTC double staining, and the myocardial expressions of apoptosis-related proteins Bax, Bcl-2 and cleaved caspase-3 were analyzed using Western blotting.</p><p><b>RESULTS</b>Myocardial IR injury resulted in significantly decreased heart rate and blood pressure in the rats (P<0.05). Compared with those in IR group, the rats with endomorphin-1 postconditioning showed significantly increased heart rate and blood pressure (P<0.05), lowered contents or activities of LDH, CK-MB, cTnI, IL-6, TNF-α, Cyt-C and MDA in the plasma (P<0.05), increased plasma SOD activity (P<0.05), reduced size of myocardial infarction, decreased myocardial expression of Bax and cleaved caspase-3 protein (P<0.05), and increased myocardial expression of Bcl-2 protein (P<0.05). All these changes induced by endomorphin-1 were obviously reversed by atractyloside postconditioning (P<0.05).</p><p><b>CONCLUSION</b>Endomorphin-1 postconditioning protects against myocardial IR injury in rats probably by inhibiting the opening of MPTP and reducing cardiac myocyte apoptosis via down-regulating cleaved caspase-3 expression.</p>

Effects of activation of mitochondrial aldehyde dehydrogenase 2 on MMP-14 and TIMP-4 in high glucose induced rat cardiomyocytes injury / 中国药理学通报

Aim To observe whether matrix metallo-proteinase-14 ( MMP-14) and tissue matrix metallopro-teinase inhibitor-4 ( TIMP-4) were involved in the car-diac-protection of mitochondrial aldehyde dehydrogen-ase 2 ( ALDH2) against high glucose induced rat pri-mary cardiomyocyte injury. Methods Rat primary cardiomyocytes were cultured. The cardiomyocyte via-bility was detected by MTT assay at different concentra-tion of glucose at different time point. After established high glucose-induced cardiomyocytes injury model, cardiomyocytes were randomly divided into 4 groups:normal control group ( NG, glucose at 5.5 mmol· L-1) , NG + Alda-1 group ( Alda-1 at 20 μmol·L-1) , high glucose group ( HG, glucose at 30 mmol·L-1) and HG+Alda-1 group. The cell viability at 48 h and oxidative stress level were detected by MTT and DHE staining methods. The protein expressions of ALDH2, MMP-14 and TIMP-4 were determined by Western blot. Results The cardiomyocytes injury model was established according to the cell activity result. Com-pared with NG group, the cell viability, the protein ex-pressions of ALDH2, MMP-14, the ratio of MMP-14/TIMP-4 were decreased, TIMP-4 protein expression and the level of oxidative stress were increased in HG group. Compared with HG group, in HG + Alda-1 group, the cell viability, the protein expressions of AL-DH2, MMP-14, the ratio of MMP-14/TIMP-4 were in-creased, the levels of oxidative stress and TIMP-4 pro-tein expression were decreased. Conclusion Activa-tion of mitochondrial ALDH2 may relieve high glucose induced cardiomyocytes injury. The protective effect was likely related to the inhibition of oxidative damage, down-regulation of MMP-14 and up-regulation of TIMP-4 proteins.

Role of autophagy in fasudil-induced Rho kinase inhibition for protection against myocardial ischemia-reperfusion injury in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the changes of autophagy in ischemic myocardium of rats treated with fasudil for inhibiting Rho kinase.</p><p><b>METHODS</b>The hearts isolated from male Sprague-Dawley rats were subjected to 30 min of occlusion of the left anterior descending artery followed by 120 min of reperfusion with or without treatment with fasudil or fasudil+Wort. The left ventricular hemodynamics were continuously recorded, and the coronary effluent was collected during the reperfusion to determine lactate dehydrogenase (LDH) levels. The mRNA expressions of autophagy-related genes Atg5 and Beclin1 and apoptosis-related genes bax and bcl-2 were detected by RT-PCR, and the protein expression of caspase-3 was detected by Western blotting.</p><p><b>RESULTS</b>Compared with I/R group, fasudil significantly improved the left ventricular developed pressure, maximal rise/fall rate of left ventricular pressure and rate pressure product, reduced LDH release during reperfusion, increased Atg5 and Beclin1 mRNA expression and the ratio of Bcl-2/Bax, and lowered caspase 3 protein expression. The autophagy inhibitor Wort significantly attenuated the effect of fasudil in the rat hearts.</p><p><b>CONCLUSION</b>Fasudil treatment for inhibiting Rho kinase promoted autophagy in ex vivo rat heart to protect against myocardial ischima-reperfusion injury possibly by reducing apoptosis of the cardiac myocytes.</p>

Effects of activation of ALDH2 by ethanol on the expression of JNK in kidney of diabetic rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the effect of activation of aldehyde dehydrogenase 2 (ALDH2) by ethanol on the expression of c-Jun N-terminal kinase (JNK) in the kidney of diabetic rats.</p><p><b>METHODS</b>Eightheen healthy male SD rats were randomly divided into 3 groups (n = 6): normal control group, diabetes group and ethanol + diabetes group. After 8 weeks, 24 h urine samples from rats were collected to detect urinary protein content. The kidney was isolated and the ratio of kidney weight/body weight (index of kidney weight) was detected. The levels of fasting blood glucose, glycosylated hemoglobin serum urea nitrogen and serum creatinine were measured. Morphological changes of renal tissue were observed by optical microscope. The protein expressions of ALDH2 and JNK in renal tissue were detected by Western blot.</p><p><b>RESULTS</b>Compared with the normal control rats, the levels of fasting blood glucose, glycosylated hemoglobin, serum urea nitrogen, serum creatinine and the index of kidney weight were increased markedly in diabetic rats. The expression of ALDH2 protein was decreased, while p-JNK, JNK protein expressions and the ratio of p-JNK/JNK were increased. The morphological observation was shown that the amount of glomerular mesangial matrix were increased, basement membrane were thickened and capillary lumen were narrowed. However,in ethanol + diabetes group, renal function was improved and the damage of renal structure was attenuated. The expression of ALDH2 protein was increased, while p-JNK, JNK and the ratio of p-JNK/JNK were decreased.</p><p><b>CONCLUSION</b>Enhanced ALDH2 expression can protect kidney in diabetic rats, which may be relevant with inhibitting the activity of JNK pathway.</p>

The changes of inducible nitric oxide synthase activity and apoptosis-related gene expression in endotoxemia-induced rat diaphragm / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the changes of inducible nitric oxide synthase (iNOS) activity and apoptosis-related genes Bcl-2, Bax and caspase-3 mRNA expressions in endotoxemia-induced rat diaphragm injury and analyze the related apoptosis mechanism.</p><p><b>METHODS</b>Thirty-two male SD rats were randomly divided into 4 groups (n = 8): control group (saline 0.5 ml ip), endotoxin 24 h, 48 h and 96 h group (endotoxin 12 mg/kg ip, animals were killed either 24, 48 or 96 h after injections). Body weight were measured, the ratio between diaphragm weight and body weight, activities of constitutive nitric oxide syntheses (cNOS), iNOS and succinate dehydrogenase (SDH) were also measured. The expressions of Bcl-2, Bax and caspase-3 mRNA were detected by RT-PCR analysis.</p><p><b>RESULTS</b>Endotoxin induced significant reductions in diaphragm mass in endotoxin 96 h group (P < 0.05). Endotoxin increased diaphragm cNOS or iNOS activities, and they were significantly higher in endotoxin 96 h group than those in endotoxin 24 h and 48 h groups, diaphragm SDH activity was reduced, and it was lower in endotoxin 96 h group than that in endotoxin 24 h and 48 h groups (P < 0.01). Endotoxin significantly increased Bax and caspase-3 mRNA expressions, and they were higher in endotoxin 48 h and 96 h groups than those in endotoxin 24 h group (P < 0.01). Endotoxin significantly reduced Bcl-2 mRNA expression and the ratio of Bcl-2/Bax, and they were lower in endotoxin 48 h and 96 h groups than those in endotoxin 24 h group (P < 0.01).</p><p><b>CONCLUSION</b>iNOS is activated in endotoxemia-induced rat diaphragm injury. It damages mitochondria, upregulates Bax expression and downregulates Bcl-2 expression, then induces caspase-3 related apoptotic pathway. These changes may cause diaphragm injury and atrophy.</p>

Anti-apoptotic role of mitochondrial aldehyde dehydrogenase 2 in myocardial ischemia/reperfusion injury in diabetic rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the anti-apoptotic effect of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/R) injury in diabetic rats.</p><p><b>METHODS</b>Normal male SD rats were divided into normal, diabetes and ethanol (the agonist of ALDH2) + diabetes groups. In the latter two groups, diabetes was induced by an intraperitoneal injection of 55 mg/kg STZ. Four weeks after the modeling, myocardial I/R was mimicked ex vivo, and lactate dehydrogenase (LDH) content in the coronary flow was determined. The activities of caspase-3 and ALDH2 were evaluated, and the expressions of Bcl-2 and Bax mRNA in the left anterior myocardium were detected using RT-PCR.</p><p><b>RESULTS</b>In diabetic group, LDH release and caspase-3 activity were increased, while ALDH2 activity and Bcl-2/Bax mRNA expression were decreased as compared to those in normal control group. Compared with the diabetic group, ALDH2 agonist ethanol significantly reduced LDH release and caspase-3 activity, increased ALDH2 activity and Bcl-2/Bax mRNA expression.</p><p><b>CONCLUSION</b>In diabetic rats, enhanced ALDH2 expression can offer mycardial protection possibly in relation to suppress cell apoptosis.</p>

Effect of ALDH2 activation against myocardial ischemia/reperfusion injury in diabetic rat / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the role of activation of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/ R) injury in diabetic rats.</p><p><b>METHODS</b>Diabetic rat model was simulated by intraperitoneal injection 55 mg/kg streptozotocin (STZ) and divided into diabetes and ethanol + diabetes groups (n = 8). After 8 weeks, myocardial ischemia/reperfusion model was mimicked in vitro. The ventricular dynamical parameters and lactate dehydrogenase (LDH) content in coronary flow were determined. The fasting blood glucose and glycosylated hemoglobin (HbA1c) level were determined by automatic biochemistry analyzer. The ALDH2 mRNA and protein expressions of left anterior myocardium were evaluated by RT-PCR and Western blot.</p><p><b>RESULTS</b>In contrast to I/R in normal rat, in diabetic rat, left ventricular development pressure (LVDP), maximal rise/fall rate of left ventricular pressure (+/- dp/dtmax) and left ventricular work (RPP) were decreased, left ventricular end diastolic pressure (LVEDP) and LDH release were increased, and ALDH2 mRNA and protein expressions were decreased; compared with I/R in diabetic rat, ALDH2 agonist ethanol significantly promoted the recovery of LVDP, +/- dp/dtmax, RPP, reduced HbA1c level, LVEDP and LDH released, ALDH2 mRNA and protein expressions were increased.</p><p><b>CONCLUSION</b>In diabetic rat, the expression of ALDH2 was decreased when heart was subjected to I/R. Enhanced mitochondrial ALDH2 expression in diabetic rat could play cardiac protective role.</p>

Activation of mitochondrial aldehyde dehydrogenase 2 and inhibition of mitochondrial permeability transition pore involved in cardioprotection of ethanol postconditioning / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate whether activation of mitochondrial aldehyde dehydrogenase 2 (ALDH2) and inhibition of mitochondrial permeability transition pore (mitoPTP) were involved in the cardioprotection of ethanol postconditioning in isolated rat heart.</p><p><b>METHODS</b>Hearts isolated from male Sprague-Dawley rats were perfused on a langendorff apparatus and subjected to 30 min of regional ischemia (occlusion of left anterior descending artery) followed by 120 min of reperfusion. The ventricular hemodynamic parameters and lactate dehydrogenase (LDH) release during reperfusion were measured. Infarct size was measured by TTC staining method and the expression of ALDH2 at mRNA level of left anterior myocardium was detected by RT-PCR.</p><p><b>RESULT</b>In contrast to ischemia and reperfusion, ethanol postconditioning improved the recovery of left ventricular developed pressure, maximal rise/fall rate of left ventricular pressure during reperfusion, reduced LDH release and infarct size. The expression of ALDH2 mRNA level was increased. Administration of mitoPTP activator atractyloside attenuated the effect of ethanol postconditioning, LDH release and infarct size were increased, and the recovery of hemodynamic parameters was inhibited. The expression of ALDH2 mRNA was decreased.</p><p><b>CONCLUSION</b>Ethanol postconditioning has cardioprotection effect, which may be associated with upregulating mitochondrial ALDH2 mRNA expression and inhibiting the opening of mitochondrial permeability transition pore.</p>

Pharmacokinetic study with N-Ile1-Thr2-63-desulfato-r-hirudin in rabbits by means of bioassay / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>AIM</b>To study the pharmacokinetic (PK) properties in rabbits treated with N-Ile(1)-Thr(2)-63-desulfato-r-hirudin (rH) newly developed in China by means of bioassay in order to provide preclinical experiment basis for its development as a novel anticoagulant agent.</p><p><b>METHODS</b>rH plasma concentration was determined using bioassay based on ex vivo antithrombin activity of rH. Normal rabbits received iv rH 4.0, 2.0 and 1.0 mg/kg or sc rH 2.0 mg/kg, respectively. The rabbits with acute severe renal failure were given iv rH 2.0 mg/kg.</p><p><b>RESULTS</b>The bioassay described in this paper met requirements for study of PK in rabbits. The major PK parameters after iv dosing were as follows: t(1/2beta) 58.4-59 min. V(d) 0.09-0.12 L/kg, CL 0.0035-0.0040 L/(kg.min); AUC were proportional to the doses, t(1/2) and CL did not change significantly with the doses. The sc bioavailability reached 94%. The rabbits suffering from acute severe renal failure presented 11-fold longer t(1/2beta) and 13-fold greater AUC than normal healthy rabbits.</p><p><b>CONCLUSION</b>rH exhibited rapid elimination, distribution was only limited to extracellular space and good absorption from sc site. The excretion of rH by kidneys played a very important role in the elimination of rH. The PK of rH could be described by the two- and one-compartment model after iv and sc dosing, respectively, and followed linear kinetics.</p>