Diabetic Cardiomyopathy Rats Research Articles

Anemarrhena asphodeloides Bunge total saponins ameliorate diabetic cardiomyopathy by modifying the PI3K/AKT/HIF-1α pathway to restore glycolytic metabolism

Ethnopharmacological relevanceBased on the theory of traditional Chinese medicine (TCM), diabetic cardiomyopathy (DCM) belongs to the category of "Xiaoke disease" according to the symptoms, and "stasis-heat" is the main pathogenesis of DCM. The Chinese medicine Anemarrhena asphodeloides Bunge (AAB), as a representative of heat-clearing and engendering fluid, is often used clinically in the treatment of DCM. Anemarrhena asphodeloides Bunge total saponins (RATS) are the main bioactive components of AAB, the modern pharmacologic effects of RATS are anti-inflammatory, hypoglycemic, and cardioprotective. However, the potential protective mechanisms of RATS against DCM remain largely undiscovered. Aim of the studyThe primary goal of this study was to explore the effect of RATS on DCM and its mechanism of action. Materials and methodsStreptozotocin and a high-fat diet were used to induce DCM in rats. UHPLC/Q-TOF-MS was used to determine the chemical components of RATS. The degenerative alterations and apoptotic cells in the heart were assessed by HE staining and TUNEL. Network pharmacology was used to anticipate the probable targets and important pathways of RATS. The alterations in metabolites and main metabolic pathways in heart tissue were discovered using 1 H-NMR metabolomics. Ultimately, immunohistochemistry was used to find critical pathway protein expression. ResultsFirst of all, UHPLC/Q-TOF-MS analysis showed that RATS contained 11 active ingredients. In animal experiments, we found that RATS lowered blood glucose and lipid levels in DCM rats, and alleviated cardiac pathological damage, and decreased cardiomyocyte apoptosis. Furthermore, the study found that RATS effectively reduced inflammatory factor release and the level of oxidative stress. Mechanistically, RATS downregulated the expression levels of PI3K, AKT, HIF-1α, LDHA, and GLUT4 proteins. Additionally, glycolysis was discovered to be a crucial pathway for RATS in the therapy of DCM. ConclusionsOur findings suggest that the protective effect of RATS on DCM may be attributed to the inhibition of the PI3K/AKT/HIF-1α pathway and the correction of glycolytic metabolism.

CircMAP3K5 promotes cardiomyocyte apoptosis in diabetic cardiomyopathy by regulating miR-22-3p/DAPK2 Axis.

Diabetic cardiomyopathy (DCM) is one of the serious complications of the accumulated cardiovascular system in the long course of diabetes. To date, there is no effective treatment available for DCM. Circular RNA (circRNA) is a novel r2egulatory RNA that participates in a variety of cardiac pathological processes. However, the regulatory role of circular RNA MAP3K5 (circMAP3K5) in DCM is largely unclear. Microarray analysis of DCM rats' heart circular RNAs was performed and the highly species-conserved circRNA mitogen-activated protein kinase kinase kinase 5 (circMAP3K5) was identified, which participates in DCM processes. High glucose-provoked cardiotoxicity leads to the up-regulation of circMAP3K5, which mechanistically contributes to cardiomyocyte cell death. Also, in high glucose-induced H9c2 cardiomyocytes, the level of apoptosis was significantly increased, as well as the expression of circMAP3K5. In contrast, the depletion of circMAP3K5 could reduce high glucose-induced apoptosis in cardiomyocytes. In terms of mechanism, circMAP3K5 acts as a miR-22-3p sponge and miR-22-3p directly target death-associated protein kinase 2 (DAPK2) in H9c2 cardiomyocytes, where in circMAP3K5 upregulates DAPK2 expression by targeting miR-22-3p. Moreover, we also found that miR-22-3p inhibitor and pcDNA DAPK2 could antagonize the protective effects brought by the depletion of circMAP3K5. CircMAP3K5 is a highly conserved noncoding RNA that is upregulated during DCM process. We concluded that circMAP3K5 promotes high glucose-induced cardiomyocyte apoptosis by regulating the miR-22-3p/DAPK2 axis. The results of this study highlight a novel and translationally important circMAP3K5-based therapeutic approach for DCM.

Aloe-Emodin Derivative, an Anthraquinone Compound, Attenuates Pyroptosis by Targeting NLRP3 Inflammasome in Diabetic Cardiomyopathy.

Diabetic cardiomyopathy (DCM) is widely recognized as a major contributing factor to the development of heart failure in patients with diabetes. Previous studies have demonstrated the potential benefits of traditional herbal medicine for alleviating the symptoms of cardiomyopathy. We have chemically designed and synthesized a novel compound called aloe-emodin derivative (AED), which belongs to the aloe-emodin (AE) family of compounds. AED was formed by covalent binding of monomethyl succinate to the anthraquinone mother nucleus of AE using chemical synthesis techniques. The purpose of this study was to investigate the effects and mechanisms of AED in treating DCM. We induced type 2 diabetes in Sprague-Dawley (SD) rats by administering a high-fat diet and streptozotocin (STZ) injections. The rats were randomly divided into six groups: control, DCM, AED low concentration (50 mg/kg/day), AED high concentration (100 mg/kg/day), AE (100 mg/kg/day), and positive control (glyburide, 2 mg/kg/day) groups. There were eight rats in each group. The rats that attained fasting blood glucose of ˃16.7 mmol/L were considered successful models. We observed significant improvements in cardiac function in the DCM rats with both AED and AE following four weeks of intragastric treatment. However, AED had a more pronounced therapeutic effect on DCM compared to AE. AED exhibited an inhibitory effect on the inflammatory response in the hearts of DCM rats and high-glucose-treated H9C2 cells by suppressing the pyroptosis pathway mediated by the nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain 3 (NLRP3) inflammasome. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially expressed genes showed a significant enrichment in the NOD-like receptor signaling pathway compared to the high-glucose group. Furthermore, overexpression of NLRP3 effectively reversed the anti-pyroptosis effects of AED in high-glucose-treated H9C2 cells. This study is the first to demonstrate that AED possesses the ability to inhibit myocardial pyroptosis in DCM. Targeting the pyroptosis pathway mediated by the NLRP3 inflammasome could provide a promising therapeutic strategy to enhance our understanding and treatment of DCM.

Suberosin Alleviates Thiazolidinedione-Induced Cardiomyopathy in Diabetic Rats by Inhibiting Ferroptosis via Modulation of ACSL4-LPCAT3 and PI3K-AKT Signaling Pathways.

Thiazolidinediones are useful antidiabetic medications. However, their use is associated with adverse side effects like edema, heart failure and bone fractures. In this study, we investigated the anti-ferroptosis effects of suberosin (SBR; a prenylated coumarin) in diabetic Sprague Dawley rats. Further, we assessed the effects of co-administration of SBR (30 and 90mg/kg/day) with thiazolidinedione (TZ at 15mg/kg) to mitigate TZ-induced cardiomyopathy in diabetic rats. Our results showed that cardiac output, stroke volume, left ventricle systolic and diastolic pressures were aggravated in diabetic rats treated with TZ alone after 4weeks. TZ treatments induced ferroptosis as well as marked histoarchitecture disarrangements in rat cardiomyocytes. The study found that optimizing volume overload alleviated cardiac hypertrophy and mitigated left ventricular dysfunction in diabetic rats co-treated with SBR. SBR co-administration with TZ reduced MDA levels in heart tissue and serum iron concentration (biomarkers of ferroptosis), downregulated mRNA expressions of LOX, ACSL4, LPCAT3, and promoted GPX4 activity as well as upregulated mRNA levels of AKT/PI3K/GSK3β as compared to the group administered with TZ at 15mg/kg. SBR co-administration also helped to retain the normal histoarchitecture of cardiomyocytes in diabetic rats. Hence, our results suggested that SBR is an effective supplement and could be prescribed to diabetic patients along with TZ but this requires further clinical trials.

Fucoidan from Sargassum wightii reduces oxidative stress through upregulating Nrf2/HO-1 signaling pathway in alloxan-induced diabetic cardiomyopathy rats.

Diabetic cardiomyopathy (DCM) is a form of cardiac dysfunction caused by diabetes, increasing heart failure and death. Studies shown that hyperglycemia-induced oxidative stress significantly affects heart structure and functional changes during diabetic cardiomyopathy. Fucoidans are sulfated polysaccharide derived from naturally available seaweeds and reported for various biological functions such as antioxidant, anti-diabetic, and anti-inflammatory. However, the therapeutic potential of Indian seaweeds against DCM remains largely unexplored. Therefore, the current study aimed to work on the cardioprotective effect of extracted fucoidan from Sargassum wightii (SwF) in alloxan-induced DCM. Diabetes (DM) was induced with alloxan monohydrate (150mg/kg-1) dissolved in Nacl (0.9%) overnight-fasted rats. Group III, IV rats were DM induced, followed by treated with SwF (150mg/kg-1) and (300mg/kg-1). Group V and VI were non-diabetic rats and received SwF (150mg/kg-1) and (300mg/kg-1). SwF reduced classical progressive DM complications such as hyperglycemia, polydipsia, polyphagia, and polyurea in alloxan-induced diabetic rats. Biochemical analysis showed that SwF decreased blood glucose, cardiac markers enzymes, and lipid peroxidation levels compared to diabetic rats. SwF administration significantly increased Nrf2, HO-1, SOD, Catalase, and NQO1 gene expression. In addition, SwF-treated rats showed reduced heart tissue damage with increased Nrf2 and HO-1 protein expression. The current research concludes that targeting oxidative stress with SwF provided an effective role inthe prevention of DCM. Thus, fucoidan could be used to develop functional food ingredients for DCM.

Ultrasound-targeted semaglutide-loaded PEG-nanoliposomes microbubble destruction protects diabetic cardiomyopathy by activating PI3K/Akt/Nrf2 signaling pathway

ObjectiveTo investigate the ameliorative effect of Semaglutide-loaded PEG-nanoliposomes (Sem-PEG-lips) combined with ultrasound-targeted microbubble destruction (UTMD) on streptozotocin (STZ)-induced diabetic cardiomyopathy (DCM) in rodents and its potential mechanisms. MethodsSem-PEG-lips were prepared by the reverse phase evaporation method. Fifty STZ-induced diabetic rats were randomly divided into DCM model group, Sem or Sem-PEG-lips alone treatment group, UTMD + Sem group and UTMD + Sem-PEG-lips group (n = 10), respectively, and used the healthy rats as normal control. During the 12-week intervention, the weight and blood glucose levels of all rats were recorded. Myocardial injury and fibrosis were observed by using H&E and Masson staining. The activity of antioxidant enzymes and the expression levels of oxidative stress-related signaling pathway markers in myocardial tissues were measured by ELISA and western blotting method, respectively. ResultsCompared with DCM rats, the body weight and blood glucose levels of those in the UTMD + Sem-PEG-lips group were significantly increased and decreased, respectively (both p < 0.05). The results of H&E and Masson staining showed that myocardial fibrosis and apoptosis were both significantly improved in combination group (both p < 0.001). Further results of ELISA and Western blot analysis showed that the activity of antioxidant enzymes in ones received combination therapy were significantly higher than that in DCM model group (all p < 0.001), and the expression of PI3K/Akt/Nrf2 signaling pathway related proteins were significantly up-regulated (all p < 0.001), and all these changes were reversed by the treatment of PI3K inhibitor. results ConclusionUTMD combined Sem-PEG-lips can reduce the oxidative stress of myocardial tissue in DCM rats by activating PI3K/Akt/Nrf2 signaling pathway, thereby improving diabetic myocardial injury.

Artemisinin attenuates type 2 diabetic cardiomyopathy in rats through modulation of AGE-RAGE/HMGB-1 signaling pathway

Diabetes mellitus is a common metabolic disorder. About two-thirds of diabetic patients develop diabetic cardiomyopathy (DCM), which becomes a challenging issue as it severely threatens the patient’s life. Hyperglycemia and the resulting advanced glycated end products (AGE) and their receptor (RAGE)/High Mobility Group Box-1 (HMGB-1) molecular pathway are thought to be key players. Recently, artemisinin (ART) has gained more attention owing to its potent biological activities beyond its antimalarial effect. Herein, we aim to evaluate the effect of ART on DCM and the possible underlying mechanisms. Twenty-four male Sprague–Dawley rats were divided into: control, ART, type 2 diabetic and type 2 diabetic treated with ART groups. At the end of the research, the ECG was recorded, then the heart weight to body weight (HW/BW) ratio, fasting blood glucose, serum insulin and HOMA-IR were evaluated. Cardiac biomarkers (CK-MB and LDH), oxidative stress markers, IL-1β, AGE, RAGE and HMGB-1 expression were also measured. The heart specimens were stained for H&E as well as Masson’s trichrome. DCM induced disturbances in all studied parameters; contrary to this, ART improved these insults. Our study concluded that ART could improve DCM through modulation of the AGE-RAGE/HMGB-1 signaling pathway, with subsequent impacts on oxidative stress, inflammation and fibrosis. ART could therefore be a promising therapy for the management of DCM.

Retraction Note: Polydatin and polydatin-loaded chitosan nanoparticles attenuate diabetic cardiomyopathy in rats.

Retraction Note: Polydatin and polydatin-loaded chitosan nanoparticles attenuate diabetic cardiomyopathy in rats.

TRPA1 deficiency attenuates cardiac fibrosis via regulating GRK5/NFAT signaling in diabetic rats

BackgroundTransient receptor potential ankyrin 1 (TRPA1) has been linked to the development of various cardiovascular diseases, but its role in diabetic cardiomyopathy is not well understood. This study aimed to investigate the protective effects of TRPA1 deficiency on diabetic cardiomyopathy in rats with streptozotocin-induced diabetes and in neonatal rat cardiac fibroblasts (CFs) exposed to high glucose (HG). MethodsCardiac TRPA1 expression levels were measured in diabetic rats. Cardiac function, remodeling, and fibrosis were analyzed in Sprague-Dawley (SD) rats and TRPA1-deficient rats with diabetic cardiomyopathy. In vitro, fibrosis was measured in CFs exposed to HG. Additionally, 1,8-cineole, a natural inhibitor of TRPA1, was used to treat SD rats with diabetic cardiomyopathy. ResultsTRPA1 expression was increased in the heart tissue of diabetic rats and in CFs treated with HG. TRPA1 deficiency significantly improved cardiac function in diabetic rats, as evidenced by improved echocardiography and reduced cardiac hypertrophy and fibrosis. In vitro, TRPA1 deficiency suppressed the transformation of HG-induced CFs into myofibroblasts. The cardioprotective effect of TRPA1 deficiency was found to inhibit cardiac fibrosis by regulating GRK5/NFAT signaling. Furthermore, inhibition of GRK5/NFAT signaling abolished the promotion of CF transformation into myofibroblasts by TRPA1 activation. Inhibition of TRPA1 activation by 1,8-cineole reduced cardiac dysfunction and remodeling in diabetic rats by regulating GRK5/NFAT signaling. ConclusionsTRPA1 deficiency reduced cardiac fibrosis in diabetic rats and inhibited HG-induced CF activation in vitro by regulating GRK5/NFAT signaling. The TRPA1 inhibitor 1,8-cineole may serve as a novel therapeutic agent for the treatment of diabetic cardiomyopathy.

Perillaldehyde improves diabetic cardiomyopathy by upregulating miR-133a-3p to regulate GSK-3β

Diabetic cardiomyopathy (DCM) is part of the most important causes of death from cardiovascular disease. Perillaldehyde (PAE), a major component of the herb perilla, has been shown to ameliorate doxorubicin-induced cardiotoxicity, but it is unclear whether PAE exerts beneficial effects on DCM. Exploring the potential molecular mechanisms of PAE for the treatment of DCM through network pharmacology and molecular docking. The SD rat type 1 diabetes model was established by a single intraperitoneal injection of streptozotocin (60 mg/kg), the cardiac function indexes of each group were detected by echocardiography; the morphological changes, apoptosis, protein expression of P-GSK-3β (S9), collagen I (Col-Ⅰ), collagen III (Col-Ⅲ) and alpha-smooth muscle actin (α-SMA), and miR-133a-3p expression levels were detected. An DCM model of H9c2 cells was established in vitro and transfected with Mimic and Inhibitor of miR-133a-3p. The results showed that PAE ameliorated cardiac dysfunction, reduced fasting glucose and cardiac weight index, and improved myocardial injury and apoptosis in DCM rats. It reduced high glucose-induced apoptosis, promoted migration and improved mitochondrial division injury in H9c2 cells. PAE decreased P-GSK-3β (S9), Col-Ⅰ, Col-Ⅲ and α-SMA protein expression and upregulated miR-133a-3p expression levels. After miR-133a-3p Inhibitor treatment, the expression of P-GSK-3β (S9) and α-SMA expression were significantly increased; after miR-133a-3p Mimic treatment, the expression of P-GSK-3β (S9) and α-SMA decreased significantly in H9c2 cells. It suggests that the mechanism of action of PAE to improve DCM may be related to the upregulation of miR-133a-3p and inhibition of P-GSK-3β expression.

Effect of artemisinin combined with allicin on improving cardiac function, fibrosis and NF-κB signaling pathway in rats with diabetic cardiomyopathy

Myocardial fibrosis and inflammation cause cardiac hypertrophy, arrhythmias, and heart failure in diabetics, a leading cause of mortality. Since it’s complicated, no drug treats diabetic cardiomyopathy. This research examined the effects of artemisinin and allicin on heart function, myocardial fibrosis, and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway in diabetic cardiomyopathy rats. A total of 50 rats were separated into 5 groups, 10 of which were the control group. 40 rats received 65 μg/g streptozotocin intraperitoneally. 37 of 40 animals fit the investigation. The artemisinin, allicin, and artemisinin/allicin groups each included nine animals. The artemisinin group received 75 mg/kg of artemisinin, the allicin group received 40 mg/kg of allicin, and the combination group received equal dosages of artemisinin and allicin gavage for four weeks. After the intervention, in each group cardiac functions, myocardial fibrosis, and NF-κB signaling pathway protein expression were assessed. All of the examined groups had greater levels of LVEDD, LVESD, LVEF, FS, E/A, and the NF-κB pathway proteins: NF-κB p65 and p-NF-κB p65 than the normal group, except for the combination group. Artemisinin and allicin did not vary statistically. Compared to the model group, the artemisinin, allicin, and combined groups showed various degrees of improvement from the pathological pattern, with more intact muscle fibers, neater arrangement, more normal cell morphology, artemisinin and allicin alleviated cardiac dysfunction and decreased myocardium fibrosis in diabetic cardiomyopathy rats by inactivating the NF-κB signaling cascade.

Effect of vinpocetine alone and in combination with enalapril in experimental model of diabetic cardiomyopathy in rats: possible involvement of PDE-1/TGF-β/ Smad 2/3 signalling pathways.

Diabetic cardiomyopathy (DC) is one of the severe secondary complications of diabetes mellitus in humans. Vinpocetine is an alkaloid having pleiotropic pharmacological effects. The present study is designed to investigate the effect of vinpocetine in DC in rats. Rats were fed a high-fat diet for nine weeks along with single dose of streptozotocin after the second week to induce DC. The haemodynamic evaluation was performed to assess the functional status of rats using the Biopac system. Cardiac echocardiography, biochemical, oxidative stress parameters and inflammatory cytokine level were analysed in addition to haematoxylin-eosin and Masson's trichome staining to study histological changes, cardiomyocyte diameter and fibrosis, respectively. Phosphodiesterase-1 (PDE-1), transforming growth factor-β (TGF-β) and p-Smad 2/3 expression in cardiac tissues were quantified using western blot/RT-PCR. Vinpocetine treatment and its combination with enalapril decreased the glucose levels compared to diabetic rats. Vinpocetine improved the echocardiographic parameters and cardiac functional status of rats. Vinpocetine decreased the cardiac biochemical parameters, oxidative stress, inflammatory cytokine levels, cardiomyocyte diameter and fibrosis in rats. Interestingly, expressions of PDE-1, TGF-β and p-Smad 2/3 were ameliorated by vinpocetine alone and in combination with enalapril. Vinpocetine is a well-known inhibitor of PDE-1 and the protective effect of vinpocetine in DC is exerted by inhibition of PDE-1 and subsequent inhibition of the expression of TGF-β/Smad 2/3.

Cyp2e1 knockdown attenuates high glucose-induced apoptosis and oxidative stress of cardiomyocytes by activating PI3K/Akt signaling.

Cyp2e1 is a crucial CYP450 enzyme participating in diabetes and cardiovascular disorder. However, the role of Cyp2e1 in diabetic cardiomyopathy (DCM) has never been reported. Thus, we intended to identify the effects of Cyp2e1 on cardiomyocytes under high glucose (HG) conditions. Identification of differentially expressed genes in DCM and control rats was performed using bioinformatics analysis based on GEO database. The Cyp2e1-knockdown H9c2 and HL-1 cells were established through transfection with si-Cyp2e1. Western blot analysis was performed to determine the expression levels of Cyp2e1, apoptosis-related proteins and PI3K/Akt signaling-associated proteins. TUNEL assay was performed to assess apoptotic rate. Reactive oxygen species (ROS) generation was examined by DCFH2-DA staining assay. From the bioinformatics analysis, Cyp2e1 was confirmed as an upregulated gene in DCM tissues. In vitro assays proved that Cyp2e1 expression was markedly increased in HG-induced H9c2 and HL-1 cells. Cyp2e1 knockdown attenuated HG-induced apoptosis in both H9c2 and HL-1 cells, as proved by deceased apoptotic rate, relative cleaved caspase-3/caspase-3 level, and caspase-3 activity. Cyp2e1 knockdown reduced ROS generation and elevated the expression level of nuclear Nrf2 in HG-induced H9c2 and HL-1 cells. Increased relative levels of p-PI3K/PI3K and p-Akt/Akt were found in Cyp2e1-knockdown H9c2 and HL-1 cells. Inhibition of PI3K/Akt using LY294002 reversed the inhibitory effects of Cyp2e1 knockdown on cell apoptosis and ROS generation on cardiomyocytes. Cyp2e1 knockdown attenuated HG-induced apoptosis and oxidative stress by activating PI3K/Akt signaling in cardiomyocytes. These findings suggested that Cyp2e1 might be potentially used as an effective therapeutic strategy for DCM.

Cardioprotective role of A-cycloglycosylated derivative of Rubiadin in diabetic cardiomyopathy in rats

Diabetic cardiomyopathy (DCM) is a kind of idiopathic heart disease, which is one of the main complications of diabetes and seriously threatens the life of diabetic patients. Rubiadin, an anthraquinone compound extracted from the stems and roots of rubiaceae, has been widely discussed for its anti-diabetes, anti-oxidation and other pharmacological effects. However, Rubiadin can cause drug-induced liver injury. Therefore, A-cycloglycosylated derivative of Rubiadin (ACDR) was obtained by modifying its structure. The purpose of this study was to investigate the effect of ACDR on DCM cardiac injury and its mechanism. The DCM animal model was established by streptozotocin, and the success of DCM was verified by blood glucose level, echocardiographic evidence of impaired myocardial functions along with enhanced myocardial fibrosis. We performed liver function tests, morphological staining of the heart and tests for oxidative stress to evaluate cardiac functional and structural changes. Finally, the expression of Na+/H+ exchanger (NHE1) protein was analyzed by immunohistochemistry and western bolt, and the expression of hairy/enhancer-of-split related with YRPW motif 1 (Hey1) and P-p38 protein was detected by immunofluorescence chemistry and western blotting. The results showed that ACDR can improve cardiac dysfunction, reduce myocardial injury, reduce oxidative stress, and protect the liver in DCM rats. Interestingly, all variations were countered by LiCl. Our study suggests that, along with controlling hyperglycemia, ACDR may improve DCM by reducing NHE1 expression, further inhibiting P-p38 activity and increasing Hey1 expression to reduce oxidative stress.

The Protective Effect of 11-Keto-β-Boswellic Acid against Diabetic Cardiomyopathy in Rats Entails Activation of AMPK

This study examined the protective effect of 11-keto-β-boswellic acid (AKBA) against streptozotocin (STZ)-induced diabetic cardiomyopathy (DC) in rats and examined the possible mechanisms of action. Male rats were divided into 5 groups (n = 8/each): (1) control, AKBA (10 mg/kg, orally), STZ (65 mg/kg, i.p.), STZ + AKBA (10 mg/kg, orally), and STZ + AKBA + compound C (CC/an AMPK inhibitor, 0.2 mg/kg, i.p.). AKBA improved the structure and the systolic and diastolic functions of the left ventricles (LVs) of STZ rats. It also attenuated the increase in plasma glucose, plasma insulin, and serum and hepatic levels of triglycerides (TGs), cholesterol (CHOL), and free fatty acids (FFAs) in these diabetic rats. AKBA stimulated the ventricular activities of phosphofructokinase (PFK), pyruvate dehydrogenase (PDH), and acetyl CoA carboxylase (ACC); increased levels of malonyl CoA; and reduced levels of carnitine palmitoyltransferase I (CPT1), indicating improvement in glucose and FA oxidation. It also reduced levels of malondialdehyde (MDA); increased mitochondria efficiency and ATP production; stimulated mRNA, total, and nuclear levels of Nrf2; increased levels of glutathione (GSH), heme oxygenase (HO-1), superoxide dismutase (SOD), and catalase (CAT); but reduced the expression and nuclear translocation of NF-κB and levels of tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6). These effects were concomitant with increased activities of AMPK in the LVs of the control and STZ-diabetic rats. Treatment with CC abolished all these protective effects of AKBA. In conclusion, AKBA protects against DC in rats, mainly by activating the AMPK-dependent control of insulin release, cardiac metabolism, and antioxidant and anti-inflammatory effects.

Pomegranate peel extract protects against the development of diabetic cardiomyopathy in rats by inhibiting pyroptosis and downregulating LncRNA-MALAT1.

Background: Pyroptosis is an inflammatory programmed cell death accompanied by activation of inflammasomes and maturation of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18. Pyroptosis is closely linked to the development of diabetic cardiomyopathy (DC). Pomegranate peel extract (PPE) exhibits a cardioprotective effect due to its antioxidant and anti-inflammatory properties. This study aimed to investigate the underlying mechanisms of the protective effect of PPE on the myocardium in a rat model of DC and determine the underlying molecular mechanism. Methods: Type 1 diabetes (T1DM) was induced in rats by intraperitoneal injection of streptozotocin. The rats in the treated groups received (150mg/kg) PPE orally and daily for 8weeks. The effects on the survival rate, lipid profile, serum cardiac troponin-1, lipid peroxidation, and tissue fibrosis were assessed. Additionally, the expression of pyroptosis-related genes (NLRP3 and caspase-1) and lncRNA-MALAT1 in the heart tissue was determined. The PPE was analyzed using UPLC-MS/MS and NMR for characterizing the phytochemical content. Results: Prophylactic treatment with PPE significantly ameliorated cardiac hypertrophy in the diabetic rats and increased the survival rate. Moreover, prophylactic treatment with PPE in the diabetic rats significantly improved the lipid profile, decreased serum cardiac troponin-1, and decreased lipid peroxidation in the myocardial tissue. Histopathological examination of the cardiac tissues showed a marked reduction in fibrosis (decrease in collagen volume and number of TGF-β-positive cells) and preservation of normal myocardial structures in the diabetic rats treated with PPE. There was a significant decrease in the expression of pyroptosis-related genes (NLRP3 and caspase-1) and lncRNA-MALAT1 in the heart tissue of the diabetic rats treated with PPE. In addition, the concentration of IL-1β and caspase-1 significantly decreased in the heart tissue of the same group. The protective effect of PPE on diabetic cardiomyopathy could be due to the inhibition of pyroptosis and downregulation of lncRNA-MALAT1. The phytochemical analysis of the PPE indicated that the major compounds were hexahydroxydiphenic acid glucoside, caffeoylquinic acid, gluconic acid, citric acid, gallic acid, and punicalagin. Conclusion: PPE exhibited a cardioprotective potential in diabetic rats due to its unique antioxidant, anti-inflammatory, and antifibrotic properties and its ability to improve the lipid profile. The protective effect of PPE on DC could be due to the inhibition of the NLRP3/caspase-1/IL-1β signaling pathway and downregulation of lncRNA-MALAT1. PPE could be a promising therapy to protect against the development of DC, but further clinical studies are recommended.

Astragaloside IV attenuates myocardial dysfunction in diabetic cardiomyopathy rats through downregulation of CD36-mediated ferroptosis.

Diabetic cardiomyopathy (DCM), one of the major complications of type 2 diabetes, is a leading cause of heart failure and death in advanced diabetes. Although there is an association between DCM and ferroptosis in cardiomyocytes, the internal mechanism of ferroptosis leading to DCM development remains unknown. CD36 is a key molecule in lipid metabolism that mediates ferroptosis. Astragaloside IV (AS-IV) confers various pharmacological effects such as antioxidant, anti-inflammatory, and immunomodulatory. In this study, we demonstrated that AS-IV was able to recover the dysfunction of DCM. In vivo experiments showed that AS-IV ameliorated myocardial injury and improved contractile function, attenuated lipid deposition, and decreased the expression level of CD36 and ferroptosis-related factors in DCM rats. In vitro experiments showed that AS-IV decreased CD36 expression and inhibited lipid accumulation and ferroptosis in PA-induced cardiomyocytes. The results demonstrated that AS-IV decreased cardiomyocyte injury and myocardial dysfunction by inhibiting ferroptosis mediated by CD36 in DCM rats. Therefore, AS-IV regulated the lipid metabolism of cardiomyocytes and inhibited cellular ferroptosis, which may have potential clinical value in DCM treatment.

MicroRNA-494 regulates high glucose-induced cardiomyocyte apoptosis and autophagy by PI3K/AKT/mTOR signalling pathway.

Diabetic cardiomyopathy (DCM) is one of the major cardiovascular complications of diabetes. However, the mechanism of DCM is not fully understood. Studies have confirmed that certain microRNAs (miRNAs/miRs) are key regulators of DCM. The aim of this study was to investigate the role and mechanism of microRNA (miR)-494 in cardiomyocyte apoptosis and autophagy induced by high glucose (HG). By establishing a rat DCM model and an HG-treated H9c2 cells injury model, cardiac function was detected by echocardiography, myocardial tissue was stained by immunohistochemistry, and Cell Counting Kit-8 assay and lactate dehydrogenase assay were used to detect the cardiomyocyte injury. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labelling staining, and western blotting was used to detect death and autophagy. The results showed that the expression level of miR-494 was higher in the myocardial tissue of DCM rats and the myocardial cells of H9c2 treated with HG. Compared with the corresponding negative control groups, miR-494 mimics enhanced HG-induced apoptosis and autophagy, whereas miR-494 inhibitors showed the opposite effect, corresponding PI3K, AKT, and mTOR phosphorylation level has changed. These findings identify that miR-494 could regulate cell apoptosis and autophagy through PI3K/AKT/mTOR signalling pathway, participating in the regulation of cardiomyocyte cell damage after HG. These findings provide new insights for the further study of the molecular mechanism and treatment of DCM.

Salvianolic acid A improve mitochondrial respiration and cardiac function via inhibiting apoptosis pathway through CRYAB in diabetic cardiomyopathy

Salvianolic acid A (SAA) is a traditional Chinese medicine that has a good therapeutic effect on cardiovascular disease. However, the underlying mechanisms by which SAA improves mitochondrial respiration and cardiac function in diabetic cardiomyopathy (DCM) remain unknown. This study aims to elucidate whether SAA had any cardiovascular protection on the pathophysiology of DCM and explored the potential mechanisms. Diabetes was induced in rats by 30 mg/kg of streptozotocin (STZ) treatment. After a week of stability, 5 mg/kg isoprenaline (ISO) was injected into the rats subcutaneously. 3 mg/kg SAA was orally administered for six weeks and 150 mg/kg Metformin was selected as a positive group. At the end of this period, cardiac function was assessed by ultrasound, electrocardiogram, and relevant cardiac injury biomarkers testing. Treatment with SAA improved cardiac function, glucose, and lipid levels, mitochondrial respiration, and suppressed myocardial inflammation and apoptosis. Furthermore, SAA treatment inhibits the apoptosis pathway through CRYAB in diabetic cardiomyopathy rats. As a result, this study not only provides new insights into the mechanism of SAA against DCM but also provides new therapeutic ideas for the discovery of anti-DCM compounds in the clinic.

Polygonatum polysaccharide attenuates inflammation through inhibiting NLRP3 inflammasome in diabetic cardiomyopathy rats

Polygonatum polysaccharide (PP) has good myocardial protection. This study aims to find whether PP can relieve inflammation and play a protective role in diabetic cardiomyopathy (DCM). Intraperitoneal injection of streptozotocin was used to induce DCM in rats, which were then separated into four groups: model group, PP-200 group (200 mg/kg PP), PP-400 group (400 mg/kg PP), and Met group (120 mg/kg metformin). Both control (NC) and model groups of rats were administered normal saline. According to the kit instructions mentioned on the kit, the levels of blood glucose, glycosylated hemoglobin, insulin (INS), and myocardial enzymes (creatinine kinase, B-type natriuretic peptide, and cardiac troponin I) were measured after 8 weeks. Cardiac function was detected by echocardiography. Hematoxylin and eosin (HE) and Masson staining were used to observe pathological changes. Myocardial RNA and protein levels of NLR family pyrin domain containing 3 (NLRP3), caspase-1, and Gasdermin D (GSDMD) were quantified through reverse transcription-polymerase chain reaction and Western blotting analysis. The in vivo findings showed that PP could reduce blood glucose, glycosylated hemoglobin, and INS levels, enhance heart functioning, restore histological alterations and myocardial enzymes, and relieve myocardial fibrosis. Furthermore, PP suppressed the expressions of NLRP3, caspase-1, and GSDMD. PP could reduce inflammation in DCM rats by suppressing NLRP3 inflammasome.