Quercetin Ameliorates Myocardial Injury in Diabetic Rats by Regulating Autophagy and Apoptosis through AMPK/mTOR Signaling Pathway.

A high-glucose environment is involved in the progression of diabetes mellitus (DM). This study aims to explore the regulatory effects of quercetin (QUE) on autophagy and apoptosis after myocardial injury in rats with DM. The type 2 DM rat models were constructed using low-dose streptozotocin (STZ) treatment combined with a high-carbohydrate (HC) diet in vivo. Compared with the control group, the body weight was decreased, whereas blood pressure, blood glucose, and the LVW/BW ratio were increased in the diabetic group. The results showed that the myocardial fibers were disordered in the diabetic group. Moreover, we found that the myocardial collagen fibers, PAS-positive cells, and apoptosis were increased, whereas the mitochondrial structure was destroyed and autophagic vacuoles were significantly reduced in the diabetic group compared with the control group. The expression levels of autophagy-related proteins LC3 and Beclin1 were decreased, whereas the expression levels of P62, Caspae-3, and Bax/Bcl-2 were increased in the diabetic group in vitro and in vivo. Moreover, QUE treatment alleviated the cellular oxidative stress reaction under high-glucose environments. The results of immunoprecipitation (IP) showed that the autophagy protein Beclin1 was bound to Bcl-2, and the binding capacity increased in the HG group, whereas it decreased after QUE treatment, suggesting that QUE inhibited the binding capacity between Beclin1 and Bcl-2, thus leading to the preservation of Beclin1-induced autophagy. In addition, the blood pressure, blood glucose, and cardiac function of rats were improved following QUE treatment. In conclusion, QUE suppressed diabetic myocardial injury and ameliorated cardiac function by regulating myocardial autophagy and inhibition of apoptosis in diabetes through the AMPK/mTOR signaling pathway.

ALDH2 attenuates ischemia and reperfusion injury through regulation of mitochondrial fusion and fission by PI3K/AKT/mTOR pathway in diabetic cardiomyopathy.

The function of mitochondrial fusion and fission is one of the important factors causing ischemia-reperfusion (I/R) injury in diabetic myocardium. Aldehyde dehydrogenase 2 (ALDH2) is abundantly expressed in heart, which involved in the regulation of cellular energy metabolism and stress response. However, the mechanism of ALDH2 regulating mitochondrial fusion and fission in diabetic myocardial I/R injury has not been elucidated. In the present study, we found that the expression of ALDH2 was downregulated in rat diabetic myocardial I/R model. Functionally, the activation of ALDH2 resulted in the improvement of cardiac hemodynamic parameters and myocardial injury, which were abolished by the treatment of Daidzin, a specific inhibitor of ALDH2. In H9C2 cardiomyocyte hypoxia-reoxygenation model, ALDH2 regulated the dynamic balance of mitochondrial fusion and fission and maintained mitochondrial morphology stability. Meanwhile, ALDH2 reduced mitochondrial ROS levels, and apoptotic protein expression in cardiomyocytes, which was associated with the upregulation of phosphorylation (p-PI3KTyr458, p-AKTSer473, p-mTOR). Moreover, ALDH2 suppressed the mitoPTP opening through reducing 4-HNE. Therefore, our results demonstrated that ALDH2 alleviated the ischemia and reperfusion injury in diabetic cardiomyopathy through inhibition of mitoPTP opening and activation of PI3K/AKT/mTOR pathway.

Docosahexaenoic acid inhibits Ca2+ influx and downregulates CaSR by upregulating microRNA-16 in pulmonary artery smooth muscle cells.

Docosahexaenoic acid (DHA) is reported to have the potential to ameliorate pulmonary arterial hypertension (PAH), while the specific mechanism is still obscure. This study aims to investigate the function of DHA in pulmonary artery smooth muscle cells (PASMCs) and explore the underlying mechanism. In our study, DHA was used to incubate PASMCs. Cytosolic-free Ca2+ concentration ([Ca2+ ]cyt) was measured using Fluo-3 AM method. Real-time polymerase chain reaction was used to detect microRNA-16 (miR-16) and calcium-sensing receptor (CaSR) messenger RNA expression levels. CCK-8 assay, BrdU assay, and Transwell assay were employed to detect the effects of DHA on proliferation and migration of PASMCs. CaSR was confirmed as a direct target of miR-16 using dual-luciferase assay, polymerase chain reaction, and Western blot analysis. It was found that DHA significantly inhibited PASMC proliferation and migration and decreased [Ca2+ ]cyt. After transfection of miR-16 mimics, proliferation and migration ability of PASMCs were significantly inhibited, whereas opposite effects were observed after miR-16 inhibition. [Ca2+ ]cyt was also inhibited by miR-16 transfection. DHA then promoted the expression of miR-16, and the effects of DHA on PASMCs were annulled when miR-16 was inhibited. CaSR was identified as a direct target of miR-16. CaSR was inhibited directly by miR-16 and indirectly by DHA. In conclusion, DHA inhibits the proliferation and migration of PASMCs, and probably ameliorates PAH via regulating miR-16/CaSR axis.

MicroRNA-143-5p modulates pulmonary artery smooth muscle cells functions in hypoxic pulmonary hypertension through targeting HIF-1α.

This paper explores the potential mechanism of microRNA-143-5p regulation effects on pulmonary artery smooth muscle cells (PASMCs) functions in hypoxic pulmonary hypertension (HPH) via targeting HIF-1a, which may offer a new idea for HPH therapy. PASMCs were transfected with mimics control/miR-143-5p mimics or inhibitor control/miR-143-5p inhibitor. We used Western blotting and RT-qPCR to detect the protein and mRNA expressions, CCK-8 assay to detect cellular viability, Annexin V-FITC/PI staining and caspase- 3/cleaved caspase-3 protein to evaluate cellular apoptosis, transwell migration experiment for cellular migration measurement and Dual luciferase reporter gene assay to prove the target of miR-143-5p. Cells under hypoxic condition presented the decreased protein and mRNA expressions of α-smooth muscle actin (SM-α-actin), Myocardin, smooth muscle myosin heavy chain (SMMHC), and smooth muscle-22α (SM22α), Calponin1 and Hypoxia-inducible factor-1α(HIF-1α), the increased cell viability and miR-143-5p level; Overexpression of miR-143-5p obviously reduced vascular smooth muscle-specific contraction marker protein levels and cellular apoptosis, increased cellular migration of PASMCs with hypoxia stimulation; Low-expression of miR-143-5p caused the opposite changes, while co-transfected with Si HIF-1 α blocked the beneficial effects of miR-143-5p inhibition on PASMCs under hypoxia. MicroRNA-143-5p can promote the phenotype conversion, proliferation and migration of pulmonary artery smooth muscle cells under hypoxic condition through direct targeting of HIF-1α.

MicroRNA­138 promotes proliferation and suppresses mitochondrial depolarization in human pulmonary artery smooth muscle cells through targeting TASK­1.

MicroRNA (miR)­138 serves an important role in the proliferation, differentiation and apoptosis of human pulmonary artery smooth muscle cells (HPASMCs), indi-cating the involvement of miR­138 in the development and progression of pulmonary artery hypertension (PAH). Potassium channel subfamily K member 3 (TASK­1), a two­pore domain K+ channel, is expressed in HPASMCs and is associated with hypoxic PAH. However, whether miR­138 mediates PAH through targeting TASK­1 is not known. In the present study, HPASMCs were transfected with miR­138 mimic to establish a PAH model in vitro, and the effects of a miR­138 inhibitor and a TASK­1 inhibitor (A293) were examined. Cell proliferation and mitochondrial membrane potential (MMP) were measured by CCK­8 assay and flow cytometry, respectively. Reverse transcription-quantitative polymerase chain reaction and western blotting were performed to examine the expression of miR­138, TASK­1, Bcl­2, caspase­3 and activation of extracellular signal­regulated kinase 1/2 (ERK1/2). A dual­luciferase reporter assay was also used to analyse the expression level of TASK­1 in HPASMCs. The results of the present study demonstrated that the miR­138 mimic promoted proliferation and MMP level, which was similar to the effect of A293 treatment on HPASMCs. However, the miR­138 inhibitor inhibited the effects induced by miR­138 mimic or A293 treatment, as demonstrated by a decrease in proliferation and MMP level in HPASMCs, accompanied by a decrease of Bcl­2 and an increase of caspase­3 expression levels, as well as ERK1/2 activation. The dual­luciferase reporter assay indicated that TASK­1 expression was negatively regulated by miR­138. The results of the present study suggested that miR­138 promoted proliferation and suppressed mitochondrial depolarization of HPASMCs by targeting TASK­1.

[Effects of irbesartan on Notch1 signaling pathway in diabetic rats with myocardial injury].

OBJECTIVE: To investigate the effects and mechanisms of irbesartan on myocardial injury in diabetic rats, and to analyze the changes of Notch1 signaling pathway in it. METHODS: Thirty rats were randomly divided into four groups:normal control group (CON, n=6), high calorie group (HC, n=6) and diabetes mellitus group (DM, n=9), irbesartan + diabetes group (Ir + DM, n=9). After modeling 8 weeks later, the body weight ratio and left ventricular weight index were measured and the serum levels of triglyceride (TG) and total cholesterol (TC) were measured by automatic biochemical analyzer. The changes of superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in myocardium of rats were determined by the kit and the expressions of B-cell lymphoma-2 (Bcl-2) and Bcl-2 assaciated X protein (Bax) protein in myocardium were detected by immunohistochemistry. The expressions of Notch1, Hes-1 and jagged-1 in myocardium of rats were detected by Western blot. RESULTS: Compared with CON group, the levels of heart weight/body weight (H/B), left ventricular weight index(LVWI) and fasting blood glucose(FBG) in HC group were not significantly changed, while the levels of blood lipids, MDA and Bax were increased significantly, and the expressions of SOD, Bcl-2 and Notch1, Hes-1 and Jagged-1 were decreased. Compared with HC group, the levels of H/B, LVWI, FBG, MDA and Bax in DM group were increased significantly, and the levels of SOD, Bcl-2 and Notch1, Hes-1 and Jagged-1 were decreased. The expression of H/B, LVWI, Notch1, Hes-1 and Jagged-1 in Ir+DM group were increased, but there was no significant difference between the other indexes. The H/B and LVWI in Ir + DM group were significantly lower than those in DM group, the levels of blood lipid and blood glucose did not change significantly, but the incidence of oxidative stress and apoptosis was reduced. While Notch1, Hes-1, Jagged -1 protein expressions were increased. CONCLUSIONS: Diabetes can induce myocardial injury, and irbesartan has myocardial protective effects through activation of Notch1.

[Effects of simvastatin on aortic vascular endothelial cell apoptosis and Bcl-2 protein expression in a rat model of atherosclerosis].

OBJECTIVE: To explore the effects of simvastatin on vascular endothelial cell apoptosis and Bcl-2 protein expression in the aorta in a rat model of atherosclerosis. METHODS: Thirty-six rats were randomized into control group (n=10), atherosclerosis model group (n=13) and simvastatin intervention group (n=13). In the latter two groups, rat models of atherosclerosis were established by intraperitoneal injection of vitamin D3 combined with high-fat feeding for 6 weeks, and the control rats were fed with regular diet. In the intervention group, the rats were further fed with high-fat diet with daily simvastatin treatment for 4 weeks. After the treatments, the pathological changes and plaque in the thoracic aorta were observed, and the expression of Bcl-2 protein was detected with immunohistochemistry. TUNEL assay was used to determine the apoptosis index (AI) of the vascular endothelial cells. RESULTS: Compared with that in the control group, Bcl-2 protein expression in the aorta of atherosclerotic rats was significantly decreased (P<0.05); simvastatin treatment obviously increased the expression of Bcl-2 protein in atherosclerotic rats (P<0.05) to a level similar to that in the control group. The AI was the highest in the model group (P<0.05) and comparable between the control and simvastatin treatment group. CONCLUSION: The therapeutic effect of simvastatin against atherosclerosis is probably mediated by up-regulation of Bcl-2 protein, which inhibits vascular endothelial cell apoptosis in rats with aortic atherosclerosis.

[Effect of high concentration glucose on the expression of ALDH2 in cardiac fibroblasts of rats].

OBJECTIVE: To observe whether acetaldehyde dehydrogenase 2 (ALDH2) is expressed in cardiac fibroblasts and investigate the change of ALDH2 in cardiac fibroblasts when cultured with high concentration of glucose. METHODS: Cultured cardiac fibroblasts were randomly divided into four groups:normal control group (5.5 mmol/L glucose), Alda-1 (the agonist of ALDH2, 20µmol/L) group, high glucose group (30 mmol/L glucose) and high glucose + Alda-1 group. Cardiac fibroblasts were identified by immunofluore-scence technique. Cell prolifera-tion was detected by MTT method after treated with drugs for 48 hours. mRNA and protein expressions of ALDH2 were determined by RT-PCR and Western blot, aimed to ensure whether ALDH2 was expressed in cardiac fibroblasts. The changes of ALDH2 protein expression in cardiac fibroblasts were tested by Western blot. RESULTS: RT-PCR and Western blot results revealed that ALDH2 was expressed in cardiac fibroblasts. Compared with normal control group, cardiac fibroblasts proliferation was increased (P < 0.05), while the protein expression of ALDH2 was reduced (P < 0.05) in high glucose group. When treated with Alda-1, the proliferation of cardiac fibroblasts was decreased (P < 0.01), while the protein expression of ALDH2 was increased (P < 0.05) in high glucose group. CONCLUSIONS: ALDH2 was expressed in cardiac fi-broblasts. Alda-1, the agonist of ALDH2 enhanced the expression of ALDH2 and inhibited the proliferation of cardiac fibroblasts when cultured with high concentration of glucose.

Activation of ALDH2 with Low Concentration of Ethanol Attenuates Myocardial Ischemia/Reperfusion Injury in Diabetes Rat Model.

The aim of this paper is to observe the change of mitochondrial aldehyde dehydrogenase 2 (ALDH2) when diabetes mellitus (DM) rat heart was subjected to ischemia/reperfusion (I/R) intervention and analyze its underlying mechanisms. DM rat hearts were subjected to 30 min regional ischemia and 120 min reperfusion in vitro and pretreated with ALDH2 activator ethanol (EtOH); cardiomyocyte in high glucose (HG) condition was pretreated with ALDH2 activator Alda-1. In control I/R group, myocardial tissue structure collapse appeared. Compared with control I/R group, left ventricular parameters, SOD activity, the level of Bcl-2/Bax mRNA, ALDH2 mRNA, and protein expressions were decreased and LDH and MDA contents were increased, meanwhile the aggravation of myocardial structure injury in DM I/R group. When DM I/R rats were pretreated with EtOH, left ventricular parameters, SOD, Bcl-2/Bax, and ALDH2 expression were increased; LDH, MDA, and myocardial structure injury were attenuated. Compared with DM + EtOH I/R group, cyanamide (ALDH2 nonspecific blocker), atractyloside (mitoPTP opener), and wortmannin (PI3K inhibitor) groups all decreased left ventricular parameters, SOD, Bcl-2/Bax, and ALDH2 and increased LDH, MDA, and myocardial injury. When cardiomyocyte was under HG condition, CCK-8 activity and ALDH2 protein expression were decreased. Alda-1 increased CCK-8 and ALDH2. Our findings suggested enhanced ALDH2 expression in diabetic I/R rats played the cardioprotective role, maybe through activating PI3K and inhibiting mitoPTP opening.

[Correlation between cytochrome 3A4+894C>T P450 gene polymorphism and outcomes of coronary intervention in patients with acute coronary syndrome].

OBJECTIVE: To investigate the relationship between plasma cytochrome P450 3A4 (CYP3A4) 894C>T gene polymorphism and the risk of recurrence of adverse cardiac events after percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). METHODS: A total of 275 patients with ACS received standard dual antiplatelet therapy and PCI. Platelet aggregation rate (PAR) was detected in each patient before and 7 days after administration of the anti-platelet drugs. Single nucleotide polymorphism of CYP3A4 gene 894C>T was detected with PCR and microarray technique. The number of coronary artery lesions was determined by PCI and the Gensini score was calculated. The patients were followed up for 3-12 months after discharge. RESULTS: No significant difference was found in CYP3A4 gene polymorphism between patients with clopidogrel resistance (CR group) and those without CR (NCR group) (P>0.05). Multivariate logistic regression analysis showed that CYP3A4 gene 894C>T polymorphism was not correlated with CR in patients with ACS (OR 1.359, P>0.05). During the follow-up, the incidence of cardiovascular events was significantly higher in CR group than in NCR group (P<0.05), but this difference was not related to the mutation type of 894C>T locus of CYP3A4 gene. CONCLUSION: The CYP3A4 gene 894C>T polymorphism is not associated with the effect of anti-platelet therapy and the risk of cardiovascular event in patients with ACS following PCI.

[Effects of low-concentrations alcohol consumption on the expression of mitofusin-2 in myocardial injury of diabetic rats].

OBJECTIVE: To observe the effects of low-concentrations of alcohol consumption on the expression of mitofusin-2 (mfn2) in myocardial injury of diabetic rats. METHODS: Diabetic rat model was simulated by intraperitoneal injection of 55 mg/kg streptozotocin (STZ) and divided into control group, diabetes mellitus(DM) and diabetes+ethanol (DM+EtOH) groups (n=6). When diabetic model was suc-ceed, daily consumption of 2.5% ethanol was used in ethanol+diabetic group after one week, then changed to 5% ethanol continued until 8 weeks. Eight weeks after the modeling, heart perfusion ex vivo. The ventricular hemodynamic parameters were recorded, the serum levels of lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) were determined by automatic biochemistry analyzer, the mfn2 protein ex-pression of left anterior myocardium was evaluated by Western blot and immunohistochemistry. RESULTS: Compared with control group, the left ventricular development pressure (LVDP), heart rate (HR) and rate pressure product (RPP) were decreased, however, left ventricular and diastolic pressure (LVEDP) and LDH, AST release were increased, the expression of mfn2 protein was decreased in DM group. Compared with DM group, LVDP, HR and RPP and the expression of mfn2 protein were increased, LVEDP and LDH, AST were decreased in DM+E-tOH group. CONCLUSIONS: The expression of mfn2 protein was decreased in myocardial injury of diabetic rats, low-concentrations of alcohol consumption increased the expression of mfn2. It suggests that mfn2 may be participated in the cardiac protective role of low-concentrations al-cohol intervene in diabetic rat.

[Effects of activation of ALDH2 by ethanol on the expression of JNK in kidney of diabetic rats].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Enhanced ALDH2 expression can protect kidney in diabetic rats, which may be relevant with inhibitting the activity of JNK pathway.

Ethanol at low concentration attenuates diabetes induced lung injury in rats model.

To observe the changes of lung injury when diabetic rats were treated with low concentration of ethanol (EtOH) and analyze the related mechanisms, male Sprague-Dawley (SD) rats were divided into control, diabetic (DM), and EtOH+DM groups. Diabetic rat was mimicked by injection of streptozotocin intraperitoneally. Fasting blood glucose (FBG) level, lung weight (LW), body weight (BW), and LW/BW were measured. The changes of lung tissue and Type II alveolar cell were detected. Pulmonary malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were measured; meanwhile, ALDH2 mRNA and protein expressions were detected by RT-PCR and western blotting, respectively. Compared with control group, in DM group, SOD activity was decreased; FBG level, LW/BW, MDA content, ALDH2 mRNA, and protein expressions were decreased. Compared with DM group, in EtOH+DM group, SOD activity, ALDH2 mRNA, and protein expressions were increased; LW/BW and MDA content were decreased. The structures of lung tissue and lamellar bodies were collapsed in DM group; the injury was attenuated in EtOH+DM group. Our findings suggested that, in diabetic rat, pulmonary ALDH2 expression was decreased accompanying lung injury. EtOH at low concentration decreased diabetes induced lung injury through activating ALDH2 expression.

Changes in cardiac mitochondrial aldehyde dehydrogenase 2 activity in relation to oxidative stress and inflammatory injury in diabetic rats.

The aim of the present study was to determine the changes in mitochondrial aldehyde dehydrogenase 2 (ALDH2) activity in relation to oxidative stress and inflammatory injury in different stages of diabetes mellitus (DM) in rats and to investigate the related mechanisms. DM in Sprague-Dawley (SD) rats was induced by a single intraperitoneal injection of 55 mg/kg streptozotocin (STZ). The rats were randomly allocated into a control group, as well as into DM4w, DM8w and DM12w groups containing DM rats 4, 8 and 12 weeks after DM induction, respectively. Ventricular hemodynamic parameters were recorded; fasting blood glucose (FBG) and glycosylated hemoglobin (HbA1c) levels were determined using an automatic biochemistry analyzer; plasma interleukin (IL)-1, IL-4 and cardiac 4-hydroxynon-2-enal (4-HNE) levels were determined using enzyme-linked immunosorbent assay (ELISA), and cardiac ALDH2 activity was measured. The mRNA expression levels of Bax and Bcl-2 of the left anterior myocardium were detected by reverse transcriptase­polymerase chain reaction (RT-PCR). FBG and HbA1c levels were increased in the DM groups compared to the control group. FBG levels were not significantly different among the DM4w, DM8w and DM12w groups, while HbA1c levels were increased with the progression of diabetes. The left ventricular developed pressure (LVDP), heart rate (HR) and rate-pressure product (RPP) were decreased, plasma IL-1 levels were increased, while IL-4 levels were decreased in the DM groups compared to the control group. Additionally, cardiac 4-HNE levels were increased, and ALDH2 activity was decreased in the DM groups compared to the control group. Bax mRNA levels were increased, Bcl-2 mRNA levels were decreased, and Bcl-2/Bax mRNA ratios were decreased in the DM groups compared to the control group. Moreover, LVDP, HR, RPP, IL-4, ALDH2 activity and Bcl-2/Bax mRNA ratios were further reduced, while 4-HNE and IL-1 levels were increased with the progression of diabetes. In conclusion, our results indicated that cardiac ALDH2 activity was further decreased with the progression of diabetes, which might be related to the increase of oxidative stress, inflammatory injury and the occurrence of apoptosis.

Activation of ALDH2 with ethanol attenuates diabetes induced myocardial injury in rats.

This study assessed changes in myocardial ALDH2 expression in the diabetic rat, in particular the diabetic rat pretreated with ALDH2 activator ethanol (EtOH). The rats were divided into six groups: control, EtOH control, diabetic rat at 4th week (DM4W), 8th week (DM8W), 12th week (DM12W) and EtOH+DM8W groups. Compared with control group, fasting blood glucose (FBG) and glycosylated hemoglobin (HbA1c) levels were increased in DM groups. HbA1c level in DM12W group was higher than in DM4W group, HbA1c level in EtOH+DM8W group was lower than in DM8W group. Compared with control group, there were no changes of LVDP, HR and ±dp/dtmax in DM4W group, but there were decreased in DM8W and DM12W groups, and increased in the EtOH+DM8W group. In DM groups, SOD activity, ALDH2 mRNA and protein levels were reduced, MDA content was increased compared with control group; which decreased further as diabetes progressed. Compared with DM8W group, SOD and ALDH2 in EtOH+DM8W group was increased, MDA was decreased. Our results indicated with the development of diabetes, myocardial ALDH2 expression was further decreased accompanying decreased ventricular function. However, activation of ALDH2 can decrease diabetes induced myocardial injury. ALDH2 may be one key endogenous cardiac protective factor in diabetic individuals.

Changes in the expression of cardiac mitofusin-2 in different stages of diabetes in rats.

The aim of this study was to investigate the role of mitofusin-2 (Mfn2) in different stages of diabetes in rats and to analyze the related mechanism(s). A diabetic model in SD rats was induced by a single intraperitoneal injection of 55 mg/kg streptozoticin (STZ). The hearts were isolated from diabetes mellitus (DM) rats at the fourth week (DM4W), eighth week (DM8W) and twelfth week (DM12W) and fasting blood glucose (FBG) levels and the ratio of heart weight to body weight (HW/BW) were measured. Malondialdehyde (MDA) content, superoxide dismutase (SOD) and caspase 3 activities were measured. The expression of Mfn2 of the left anterior myocardium at the mRNA level was detected using RT­PCR. In contrast to the normal group, in the DM4W, DM8W and DM12W groups, there was a significant increase in the FBG levels, but no difference among the DM4W, DM8W and DM12W groups. The HW/BW ratio as well as the MDA content were increased, while SOD activity was reduced. Caspase­3 activity was increased, while the expression of Mfn-2 mRNA levels was reduced. In addition, with the development of diabetic cardiomyopathy, the contents of MDA and caspase 3 were increased, whereas SOD activity and Mfn-2 mRNA levels were further reduced. In conclusion, our results indicated that with the development of diabetes, the expression of cardiac Mfn2 has showed a decrease, which may be associated with the decrease of antioxidant ability and progression of apoptosis.

[Effect of ALDH2 activation against myocardial ischemia/reperfusion injury in diabetic rat].

OBJECTIVE: To observe the role of activation of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/ R) injury in diabetic rats. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Anti-apoptotic role of mitochondrial aldehyde dehydrogenase 2 in myocardial ischemia/reperfusion injury in diabetic rats].

OBJECTIVE: To evaluate the anti-apoptotic effect of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/R) injury in diabetic rats. METHODS: 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. RESULTS: 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. CONCLUSION: In diabetic rats, enhanced ALDH2 expression can offer mycardial protection possibly in relation to suppress cell apoptosis.