Delta opioid receptor agonist attenuates lipopolysaccharide-induced myocardial injury by regulating autophagy

Delta opioid peptide [D-ala2, D-leu5]-Enkephalin's ability to enhance mitophagy via TRPV4 to relieve ischemia/reperfusion injury in brain microvascular endothelial cells

BACKGROUND

Local brain tissue can suffer from ischaemia/reperfusion (I/R) injury, which lead to vascular endothelial damage. The peptide δ opioid receptor (δOR) agonist [D-ala2, D-leu5]-Enkephalin (DADLE) can reduce apoptosis caused by acute I/R injury in brain microvascular endothelial cells (BMECs).

OBJECTIVE

This study aims to explore the mechanism by which DADLE enhances the level of mitophagy in BMECs by upregulating the expression of transient receptor potential vanilloid subtype 4 (TRPV4).

METHODS

BMECs were extracted and made to undergo oxygen-glucose deprivation/reoxygenation (OGD/R) accompanied by DADLE. RNA-seq analysis revealed that DADLE induced increased TRPV4 expression. The CCK-8 method was used to assess the cellular viability; quantitative PCR (qPCR) was used to determine the mRNA expression of Drp1; western blot was used to determine the expression of TRPV4 and autophagy-related proteins; and calcium imaging was used to detect the calcium influx. Autophagosomes in in the cells' mitochondria were observed by using transmission electron microscopy. ELISA was used to measure ATP content, and a JC-1 fluorescent probe was used to detect mitochondrial membrane potential.

RESULTS

When compared with the OGD/R group, OGD/R+DADLE group showed significantly enhanced cellular viability; increased expression of TRPV4, Beclin-1, LC3-II/I, PINK1 and Parkin; decreased p62 expression; a marked rise in calcium influx; further increases in mitophagy, an increase in ATP synthesis and an elevation of mitochondrial membrane potential. These protective effects of DADLE can be blocked by a TRPV4 inhibitor HC067047 or RNAi of TRPV4.

CONCLUSION

DADLE can promote mitophagy in BMECs through TRPV4, improving mitochondrial function and relieving I/R injury.

Current insight on the mechanisms of programmed cell death in sepsis-induced myocardial dysfunction

Sepsis is a clinical syndrome characterized by a dysregulated host response to infection, leading to life-threatening organ dysfunction. It is a high-fatality condition associated with a complex interplay of immune and inflammatory responses that can cause severe harm to vital organs. Sepsis-induced myocardial injury (SIMI), as a severe complication of sepsis, significantly affects the prognosis of septic patients and shortens their survival time. For the sake of better administrating hospitalized patients with sepsis, it is necessary to understand the specific mechanisms of SIMI. To date, multiple studies have shown that programmed cell death (PCD) may play an essential role in myocardial injury in sepsis, offering new strategies and insights for the therapeutic aspects of SIMI. This review aims to elucidate the role of cardiomyocyte's programmed death in the pathophysiological mechanisms of SIMI, with a particular focus on the classical pathways, key molecules, and signaling transduction of PCD. It will explore the role of the cross-interaction between different patterns of PCD in SIMI, providing a new theoretical basis for multi-target treatments for SIMI.

Research Progress on the Mechanism of Sepsis Induced Myocardial Injury

Sepsis is an abnormal condition with multiple organ dysfunctions caused by the uncontrolled infection response and one of the major diseases that seriously hang over global human health. Besides, sepsis is characterized by high morbidity and mortality, especially in intensive care unit (ICU). Among the numerous subsequent organ injuries of sepsis, myocardial injury is one of the most common complications and the main cause of death in septic patients. To better manage septic inpatients, it is necessary to understand the specific mechanisms of sepsis induced myocardial injury (SIMI). Therefore, this review will elucidate the pathophysiology of SIMI from the following certain mechanisms: apoptosis, mitochondrial damage, autophagy, excessive inflammatory response, oxidative stress and pyroptosis, and outline current therapeutic strategies and potential approaches in SIMI.

Dehydrocorydaline Protects Against Sepsis-Induced Myocardial Injury Through Modulating the TRAF6/NF-κB Pathway

We aim to investigate the effect and mechanism of dehydrocorydaline (Deh), an alkaloidal component isolated from Rhizoma corydalis, in the treatment of sepsis-mediated myocardial injury. Lipopolysaccharide (LPS) was taken to construct an in-vitro sepsis-myocardial injury models H9C2 cardiomyocytes. The in-vivo model of sepsis in C57BL/6 mice was induced by intraperitoneal injection of Escherichia coli (E. coli). The in-vitro and in-vivo models were treated with Deh in different concentrations, respectively. Hematoxylin-eosin (HE) staining, Masson staining, and immunohistochemistry (IHC) staining were taken to evaluate the histopathological changes of the heart. ELISA was applied to evaluate the levels of inflammatory factors, including IL-6, IL-1β, TNFα, IFNγ, and oxidized factors SOD, GSH-PX in the plasma or culture medium. Western blot was used to measure the expressions of Bax, Bcl2, Caspase3, iNOS, Nrf2, HO-1, TRAF6, NF-κB in heart tissues and cells. The viability of H9C2 cardiomyocytes was detected by the CCK8 method and BrdU assay. The ROS level in the H9C2 cardiomyocytes were determined using immunofluorescence. As a result, Deh treatment improved the survival of sepsis mice, reduced TUNEL-labeled apoptosis of cardiomyocytes. In vitro, Deh enhanced the viability of LPS-induced H9C2 cardiomyocytes and inhibited cell apoptosis. Additionally, Deh showed significant anti-inflammatory and anti-oxidative stress functions via decreasing IL-1β, IL-6, TNFα, and IFNγ levels, mitigating ROS level, up-regulating Nrf2/HO-1, SOD, and GSH-PX expressions dose-dependently. Mechanistically, Deh inhibited TRAF6 expression and the phosphorylation of NF-κB p65. The intervention with a specific inhibitor of TRAF6 (C25-140) or NF-κB inhibitor (BAY 11-7082) markedly repressed the protective effects mediated by Deh. In conclusion, Deh restrains sepsis-induced cardiomyocyte injury by inhibiting the TRAF6/NF-κB pathway.

Protective Role of Coenzyme Q10 in Acute Sepsis-Induced Liver Injury in BALB/c Mice

Sepsis increases the risk of the liver injury development. According to the research works, coenzyme Q10 exhibits hepatoprotective properties in vivo as well as in vitro. Current work aimed at investigating the protective impacts of coenzyme Q10 against liver injury in septic BALB/c mice. The male BALB/c mice were randomly segregated into 4 groups: the control group, the coenzyme Q10 treatment group, the puncture and cecal ligation group, and the coenzyme Q10+cecal ligation and puncture group. Cecal ligation and puncture was conducted after gavagaging the mice with coenzyme Q10 during two weeks. Following 48 h postcecal ligation and puncture, we estimated hepatic biochemical parameters and histopathological changes in hepatic tissue. We evaluated the expression of factors associated with autophagy, pyroptosis, and inflammation. Findings indicated that coenzyme Q10 decreased the plasma levels in alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase in the cecal ligation and puncture group. Coenzyme Q10 significantly inhibited the elevation of sequestosome-1, interleukin-1β, oligomerization domain-like receptor 3 and nucleotide-binding, interleukin-6, and tumor necrosis factor-α expression levels; coenzyme Q10 also increased beclin 1 levels. Coenzyme Q10 might be a significant agent in the treatment of liver injury induced by sepsis.

Delta opioid peptide [d-Ala2, d-Leu5] enkephalin confers neuroprotection by activating delta opioid receptor-AMPK-autophagy axis against global ischemia

Background

Ischemic stroke poses a severe risk to human health worldwide, and currently, clinical therapies for the disease are limited. Delta opioid receptor (DOR)-mediated neuroprotective effects against ischemia have attracted increasing attention in recent years. Our previous studies revealed that DOR activation by [d-Ala2, d-Leu5] enkephalin (DADLE), a selective DOR agonist, can promote hippocampal neuronal survival on day 3 after ischemia. However, the specific molecular and cellular mechanisms underlying the DOR-induced improvements in ischemic neuronal survival remain unclear.

Results

We first detected the cytoprotective effects of DADLE in an oxygen–glucose deprivation/reperfusion (OGD/R) model and observed increased viability of OGD/R SH-SY5Y neuronal cells. We also evaluated changes in the DOR level following ischemia/reperfusion (I/R) injury and DADLE treatment and found that DADLE increased DOR levels after ischemia in vivo and vitro. The effects of DOR activation on postischemic autophagy were then investigated, and the results of the animal experiment showed that DOR activation by DADLE enhanced autophagy after ischemia, as indicated by elevated LC3 II/I levels and reduced P62 levels. Furthermore, the DOR-mediated protective effects on ischemic CA1 neurons were abolished by the autophagy inhibitor 3-methyladenine (3-MA). Moreover, the results of the cell experiments revealed that DOR activation not only augmented autophagy after OGD/R injury but also alleviated autophagic flux dysfunction. The molecular pathway underlying DOR-mediated autophagy under ischemic conditions was subsequently studied, and the in vivo and vitro data showed that DOR activation elevated autophagy postischemia by triggering the AMPK/mTOR/ULK1 signaling pathway, while the addition of the AMPK inhibitor compound C eliminated the protective effects of DOR against I/R injury.

Conclusion

DADLE-evoked DOR activation enhanced neuronal autophagy through activating the AMPK/mTOR/ULK1 signaling pathway to improve neuronal survival and exert neuroprotective effects against ischemia.

Ulinastatin attenuates lipopolysaccharide-induced cardiac dysfunction by inhibiting inflammation and regulating autophagy

Ulinastatin exerts protective effects against lipopolysaccharide (LPS)-induced cardiac dysfunction. Autophagy has been demonstrated to serve an important role in sepsis-induced cardiomyopathy; however, whether ulinastatin has an anti-autophagic effect in sepsis requires further investigation. The present study aimed to determine the protective effects of ulinastatin on cardiac dysfunction and its role in autophagy during sepsis. C57BL/6J mice were randomly divided into a control, LPS and LPS + ulinastatin group, the survival status of the mice was observed every 6 h and the survival rate at each time point was calculated for 7 days. Furthermore, JC-1 dye and ELISAs were used to analyze the mitochondrial membrane potential (MMP) and serum cardiac troponin I (cTnI) levels, respectively. Western blotting and ELISAs were used to measure the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6. In addition, the cardiac ultrastructure and the number of autophagosomes formed were visualized using transmission electron microscopy, and the pathological changes in the myocardial tissues were analyzed using hematoxylin & eosin staining. Finally, the expression levels of autophagy-related proteins were analyzed using western blotting and immunofluorescence staining. The current study indicated that ulinastatin significantly improved the survival rate of septic mice. It was suggested that ulinastatin may protect against LPS-induced myocardium injury through its anti-inflammatory activity, as decreased cTnI levels, increased MMP and decreased expression levels of TNF-α and IL-6 were all observed following ulinastatin treatment. Furthermore, the number of autophagosomes formed, and the expression levels of microtubule-associated protein light chain 3 and Beclin 1 were significantly decreased following ulinastatin treatment. It was further observed that ulinastatin suppressed LPS-induced autophagosome formation, as indicated by the accumulation of sequestosome 1/p62, and the elimination of lysosome-associated membrane glycoprotein 1. In conclusion, the results of the present study suggested that ulinastatin treatment may improve survival and exert a protective effect over LPS-induced cardiac dysfunction. Furthermore, this protective effect may be associated with its anti-inflammatory and anti-autophagic activity.

Endogenous opiates and behavior: 2017

This paper is the fortieth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2017 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Melatonin attenuates nicotine-induced autophagy and neurological changes by decreasing the production of reactive oxygen species

Purpose: The aim of this study was to explore the mechanism of neurological changes underlying the toxicity of nicotine.Materials and methods: Rat pheochromocytoma 12 (PC12) cells and human neuroglia (HM) cells were used. The ROS levels of the cells were detected by the FACScan. Autophagy flux was monitored by a tandem monomeric RFP-GFP-tagged LC3 lentivirus. The autophagic proteins LC3, SQSTM1/p62 and Beclin1 were detected by western blot assay. In order to evaluate the effects of nicotine and melatonin on the morphological changes of neurons, primary cortical neurons were obtained and immunocytochemistry of TUBB3 tubulin were conducted.Results: Nicotine increased the levels of reactive oxygen species (ROS) in PC12 and HM cells in a concentration-dependent manner. Microscopy showed increased autophagic flux in nicotine-treated PC12 cells. Subsequent western blotting results showed that nicotine induced increase in the levels of LC3B-II and Beclin1, and decreased SQSTM1/p62 in a concentration-dependent manner. Finally, nicotine treatment reduced the length of TUBB3-positive axons and dendrites. Melatonin, a mitochondrially targeted antioxidant, reduced the ROS level, and blocked autophagy activation and the morphologic structural changes induced by nicotine.Conclusions: Our results suggested that the role of nicotine in neuronal toxicity maybe through the induction of ROS and the subsequent activation of autophagy. These effects could be restored by melatonin.

Halofuginone protects against advanced glycation end products‑induced injury of H9C2 cells via alleviating endoplasmic reticulum stress‑associated apoptosis and inducing autophagy

Advanced glycation end products (AGEs) have been reported to serve an important role in the stiffening of cardiac tissues and myocardial cell injury. Serious myocardial cell injury can result in various heart diseases with high mortality. Halofuginone (HF), which possesses marked anti-inflammatory and antifibrotic effects, has recently been applied to inhibit the effects of cardiac stress. The present study aimed to investigate the potential effects of HF and its underlying mechanism in the treatment of AGEs-induced H9C2 cardiomyocyte damage. The western blot results of the present study demonstrated that HF may reduce the expression levels of myocardial injury markers, including myoglobin, creatine kinase MB and cardiac troponin I. In addition, flow cytometric analysis indicated that the production of reactive oxygen species (ROS) was significantly decreased by HF. Additionally, endoplasmic reticulum (ER) stress was suppressed in response to treatment with HF, as observed by low expression levels of ER stress-associated proapoptotic proteins (CCAAT/enhancer-binding protein homologous protein and cleaved caspase-12); overexpression of prosurvival proteins (growth arrest and DNA damage-inducible protein GADD34 and binding immunoglobulin protein) was also reported. Furthermore, the expression levels of microtubule-associated proteins 1A/1B light chain 3B (LC3)II/LC3I and Beclin 1 were elevated, whereas P62 expression levels were reduced following treatment with HF. These findings, together with immunofluorescence staining of LC3, indicated that HF may induce autophagy. Finally, the protective effects of HF on AGEs-treated H9C2 cells were reversed following treatment with the inhibitor 3-methyladenine, as indicated by inhibition of autophagy, and increases in apoptosis, ROS production and the ER stress response. Collectively, the findings of the present study suggested that the protective effects of HF against AGEs-induced myocardial cell injury may be associated with the induction of autophagy and amelioration of ROS-mediated ER stress and apoptosis. These findings may contribute to the development of a novel therapeutic method to inhibit the progression of myocardial cell injury.

Alleviation of sepsis‑induced cardiac dysfunction by overexpression of Sestrin2 is associated with inhibition of p‑S6K and activation of the p‑AMPK pathway

Sepsis-induced myocardial injury is one of the manifestations of multiple organ dysfunction in sepsis. The aim of the present study was to determine the mechanism of alleviation of lipopolysaccharide (LPS)-induced injury on cardiomyocytes by Sestrin2. A sepsis model using LPS injection was constructed in Sprague-Dawley (SD) rats, and after 6, 12 and 24 h, rat blood was collected and cardiac troponin T (CTnT) levels were determined using ELISA. Heart specimens were excised, tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) levels were detected by ELISA, malondialdehyde (MDA) levels were estimated using colorimetric analysis, and phosphorylated (p)-S6K and p-AMP-activated protein kinase (AMPK) levels were determined by western blot analysis. In the septic rats, phenomenon of myocardial fiber rupture, interstitial edema and inflammatory cell infiltration were observed under light microscope. Following LPS injection, CTnT in serum and MDA in myocardial homogenate were increased time-dependently. TNF-α and IL-6 levels were significantly increased, with a peak at 6 h. p-S6K levels were adaptively downregulated, and levels of p-AMPK and Sestrin2 were adaptively upregulated by LPS. In LPS-injured H9c2 cells, Sestrin2 overexpression attenuated the LPS-mediated inhibitory effects on cell viability, suppressed LPS-mediated increase in CTnT, TNF-α, IL-6 and MDA levels, as well as attenuated p-S6K levels and elevated p-AMPK and Sestrin2 levels. Sestrin2 interference showed the opposite effect. Sestrin2 promoted cell viability and inhibited the inflammatory responses of LPS-injured myocardial cells. The phenomena may be associated with inhibition of p-S6K and activation of the p-AMPK pathway.

Protective role of thymoquinone in sepsis-induced liver injury in BALB/c mice

Sepsis increases the risk of developing liver injury. Previous studies have demonstrated that thymoquinone (TQ) exhibits hepatoprotective properties in vivo as well as in vitro. The present study aimed to investigate the underlying mechanisms of the protective effects of TQ against liver injury in septic BALB/c mice. Male BALB/c mice (age, 8 weeks) were randomly divided into four groups, namely, the control, TQ (50 mg/kg/day) treatment, cecal ligation and puncture (CLP), and TQ + CLP groups. CLP was performed following gavage of TQ for 2 weeks. At 48 h post-CLP, the histopathological alterations in the liver tissue (LT) and plasma levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were assessed. The present study evaluated microtubule-associated protein light chain 3 (LC3), sequestosome-1 (p62) and beclin 1 protein expression by western blotting and immunostaining, as well as interleukin (IL)-6, IL-1β, IL-10, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) mRNA expression by RT-qPCR. The results of the present study indicated that administration of TQ to mice reduced the histological alterations caused by CLP in LT. TQ inhibited the plasma levels of ALT, AST and ALP in the CLP group. TQ significantly inhibited the elevation of p62, IL-1β, IL-6, MCP-1 and TNF-α levels as well as increased the LC3, beclin 1 and IL-10 levels in LT. PI3K expression in the TQ + CLP group was significantly decreased compared with that in the CLP group. TQ treatment effectively modulated the expression levels of p62, LC3, beclin 1, PI3K and proinflammatory cytokines, and may be an important agent for the treatment of sepsis-induced liver injury.

Sepsis-induced myocardial dysfunction

PURPOSE OF REVIEW

Sepsis leads to a complex intramyocardial inflammatory response that results in sepsis-induced myocardial dysfunction. Here, recent findings are reviewed in a physiologic context.

RECENT FINDINGS

Decreased systolic contractility during sepsis limits ventricular ejection and stroke volume. Initially, this effect is compensated for by increased diastolic filling during volume resuscitation. Reduced afterload due to arterial vasodilation also compensates so that cardiac output can be maintained or increased. Recent results recognize the importance of diastolic dysfunction, reduced ventricular diastolic compliance that impedes ventricular filling. Diastolic dysfunction becomes increasingly important as severity of septic shock increases. When impaired ventricular ejection is coupled with limited diastolic filling, stroke volume must decrease. Accordingly, diastolic dysfunction is more closely related to mortality than systolic dysfunction. Recent trials of beta-adrenergic agonists and levosimendan have been disappointing, while approaches to modulating the intramyocardial inflammatory response show promise.

SUMMARY

Sepsis-induced myocardial dysfunction is increasingly recognized as a major contributor to outcome of septic shock. Significant strides have been made in understanding the intramyocardial inflammatory response that causes myocardial dysfunction. A number of novel approaches show promise by modulating the intramyocardial inflammatory response.

Effects and Mechanisms of Tea for the Prevention and Management of Diabetes Mellitus and Diabetic Complications: An Updated Review

Diabetes mellitus has become a serious and growing public health concern. It has high morbidity and mortality because of its complications, such as diabetic nephropathy, diabetic cardiovascular complication, diabetic neuropathy, diabetic retinopathy, and diabetic hepatopathy. Epidemiological studies revealed that the consumption of tea was inversely associated with the risk of diabetes mellitus and its complications. Experimental studies demonstrated that tea had protective effects against diabetes mellitus and its complications via several possible mechanisms, including enhancing insulin action, ameliorating insulin resistance, activating insulin signaling pathway, protecting islet β-cells, scavenging free radicals, and decreasing inflammation. Moreover, clinical trials also confirmed that tea intervention is effective in patients with diabetes mellitus and its complications. Therefore, in order to highlight the importance of tea in the prevention and management of diabetes mellitus and its complications, this article summarizes and discusses the effects of tea against diabetes mellitus and its complications based on the findings from epidemiological, experimental, and clinical studies, with the special attention paid to the mechanisms of action.

Delta Opioid Peptide [d-Ala2, d-Leu5] Enkephalin (DADLE) Exerts a Cytoprotective Effect in Astrocytes Exposed to Oxygen-Glucose Deprivation by Inducing Autophagy

Astrocytes protection and functional regulation are important strategies to protect against neuronal damage caused by ischemia. Activation of the delta opioid receptor (DOR) could reduce astrocytes damage, although the mechanism remains unclear. The present study aimed to test the effect of DOR activation on autophagy in astrocytes exposed to oxygen-glucose deprivation (OGD), and to further investigate whether this effect has a protective effect on astrocytes. Primary cultured rat cortical astrocytes were treated with various doses of [d-Ala2, d-Leu5]-Enkephalin (DADLE, a selective DOR agonist) followed by 6 h OGD. Cell viability was evaluated by CCK-8 assay and lactate dehydrogenase release. Autophagic vacuole was analyzed with LC3 immunofluorescent staining. The levels of autophagy and apoptosis-related proteins were analyzed by western blot. Results demonstrated that treatment with 10 nM DADLE was sufficient to increase cell viability and induced autophagy in astrocytes. The DADLE-induced autophagy displayed a cytoprotective effect on astrocytes. Inhibition of autophagy by 3-methyladenine (3-MA, an autophagy inhibitor) reversed the protective effect of DADLE. Naltrindole (a DOR antagonist) only partially antagonized the role of DADLE, which indicated that DADLE might have a cytoprotective mechanism independent of DOR. Further results showed that DADLE significantly enhanced the level of Bcl-2 protein and reduced the level of Bax protein in astrocytes exposed to OGD. Our results suggest a novel mechanism in which DADLE induces autophagy in astrocytes and exerts cytoprotective effects by inhibiting apoptosis.

Regulation of autophagy by tea polyphenols in diabetic cardiomyopathy

OBJECTIVE

To investigate the effect of tea polyphenols on cardiac function in rats with diabetic cardiomyopathy, and the mechanism by which tea polyphenols regulate autophagy in diabetic cardiomyopathy.

METHODS

Sixty Sprague-Dawley (SD) rats were randomly divided into six groups: a normal control group (NC), an obesity group (OB), a diabetic cardiomyopathy group (DCM), a tea polyphenol group (TP), an obesity tea polyphenol treatment group (OB-TP), and a diabetic cardiomyopathy tea polyphenol treatment group (DCM-TP). After successful modeling, serum glucose, cholesterol, and triglyceride levels were determined; cardiac structure and function were inspected by ultrasonic cardiography; myocardial pathology was examined by staining with hematoxylin-eosin; transmission electron microscopy was used to observe the morphology and quantity of autophagosomes; and expression levels of autophagy-related proteins LC3-II, SQSTM1/p62, and Beclin-1 were determined by Western blotting.

RESULTS

Compared to the NC group, the OB group had normal blood glucose and a high level of blood lipids; both blood glucose and lipids were increased in the DCM group; ultrasonic cardiograms showed that the fraction shortening was reduced in the DCM group. However, these were improved significantly in the DCM-TP group. Hematoxylin-eosin staining showed disordered cardiomyocytes and hypertrophy in the DCM group; however, no differences were found among the remaining groups. Transmission electron microscopy revealed that the numbers of autophagosomes in the DCM and OB-TP groups were obviously increased compared to the NC and OB groups; the number of autophagosomes in the DCM-TP group was reduced. Western blotting showed that the expression of LC3-II/I and Beclin-1 increased obviously, whereas the expression of SQSTM1/p62 was decreased in the DCM and OB-TP groups (P<0.05).

CONCLUSIONS

Tea polyphenols had an effect on diabetic cardiomyopathy in rat cardiac function and may alter the levels of autophagy to improve glucose and lipid metabolism in diabetes.