OBJECTIVES: To investigate the effects of quercetin on cuproptosis and L-type calcium currents in the myocardium of diabetic rats. METHODS: Forty SD rats were randomized into control group and diabetic model groups. The rat models of diabetes mellitus (DM) induced by high-fat and high-sugar diet combined with streptozotocin (STZ) injection were further divided into DM model group, quercetin treatment group, and empagliflozin treatment group (n=10). Blood glucose and body weight were measured every other week, and cardiac function of the rats was evaluated using echocardiography. HE staining, Sirius red staining, and wheat germ agglutinin (WGA) analysis were used to observe the changes in myocardial histomorphology, and serum copper levels and myocardial FDX1 expression were detected. In cultured rat cardiomyocyte H9c2 cells with high-glucose exposure, the effects of quercetin and elesclomol, alone or in combination, on intracellular CK-MB and LDH levels and FDX1 expression were assessed, and the changes in L-type calcium currents were analyzed using patch-clamp technique. RESULTS: The diabetic rats exhibited elevated blood glucose, reduced body weight, impaired left ventricular function, increased serum copper levels and myocardial FDX1 expression, decreased L-type calcium currents, and prolonged action potential duration. Quercetin and empagliflozin treatment significantly lowered blood glucose, improved body weight, and restored cardiac function of the diabetic rats, and compared with empagliflozin, quercetin more effectively reduced serum copper levels, downregulated FDX1 expression, and enhanced myocardial L-type calcium currents in diabetic rats. In H9c2 cells, high glucose exposure significantly increased myocardial expressions of FDX1, CK-MB and LDH, which were effectively lowered by quercetin treatment; Elesclomol further elevated FDX1, CK-MB and LDH levels in the exposed cells, and these changes were not significantly affected by the application of quercetin. CONCLUSIONS Quercetin ameliorates myocardial injury in diabetic rats possibly by suppressing myocardial cuproptosis signaling and restoring L-type calcium channel activity.
Animals ; Quercetin/pharmacology* ; Calcium Channels, L-Type/metabolism* ; Diabetes Mellitus, Experimental/metabolism* ; Rats, Sprague-Dawley ; Rats ; Myocytes, Cardiac/drug effects* ; Myocardium/pathology* ; Male

OBJECTIVES: To study the mechanism mediating the protective effect of asiaticoside (AS) against myocardial ischemia-reperfusion injury (MIRI) in rats. METHODS: Fifty SD rats were randomized into sham-operated group, MIRI model group and AS treatment group. AS treatment was administered at low, moderate and high doses by daily gavage for 2 weeks before MIRI modeling (n=10). Serum levels of lactate dehydrogenase (LDH), creatine kinase isoenzyme (CK-MB), interleukin-18 (IL-18) and IL-1β, the volume of myocardial infarction and ischemia, and myocardial pathologies of the rats were determined or observed. The protein expression levels of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1β and IL-18 in the myocardial tissues were detected using Western blotting. The changes in the expression levels of these proteins were also detected in H9C2 cells with AS pretreatment prior to hypoxia-reoxygenation (H/R) injury. RESULTS: The rats models of MIRI exhibited significant myocardial infarction and ischemia with increased serum levels of LDH and CK-MB and myocardial expressions of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1β and IL-18. AS pretreatment effectively reduced myocardial infarction volume in the rat models and significantly reduced serum LDH and CK-MB levels and the protein levels in the myocardial tissue in a dose-dependent manner. In the H9C2 cell model of H/R injury, AS pretreatment significantly suppressed the elevation of the protein expressions of NLRP3, ASC, caspase-1, GSDMD, GSDMD-N, IL-1β and IL-18. Molecular docking studies showed that AS had a strong binding affinity with NLRP3. CONCLUSIONS Asiaticoside can alleviate MIRI in rats possibly by inhibiting NLRP3 inflammasome-mediated pyroptosis.
Animals ; Myocardial Reperfusion Injury/metabolism* ; NLR Family, Pyrin Domain-Containing 3 Protein/metabolism* ; Pyroptosis/drug effects* ; Rats, Sprague-Dawley ; Rats ; Inflammasomes/metabolism* ; Triterpenes/pharmacology* ; Interleukin-18/metabolism* ; Male ; Interleukin-1beta/metabolism* ; Caspase 1/metabolism*

Objective To analyze the correlation of copper death inducer ferredoxin 1(FDX1)and lipoic acid(LA)with the occurrence and severity of coronary atherosclerosis and explore their roles in coronary heart disease(CHD).Methods We analyzed the data of 226 patients undergoing coronary artery angiography(CAG)in our hospital between October,2021 and October,2022,including 47 patients with normal CAG findings(control group)and 179 patients with mild,moderate or severe coronary artery stenosis(CHD group).Serum FDX1 and LA levels were determined with ELISA for all the patients.We also examined pathological changes in the aorta of normal and ApoE-/-mice using HE staining and observed collagen fiber deposition with Sirius red staining.Immunohistochemistry was used to detect the expression and distribution of FDX1 and LA in the aorta,and RT-PCR was performed to detect the expressions of FDX1,LIAS and ACO2 mRNAs in the myocardial tissues.Results Compared with the control patients,CHD patients had significantly lower serum FDX1 and LA levels,which decreased progressively as coronary artery stenosis worsened(P<0.01)and as the number of involved coronary artery branches increased(P<0.05).Serum FDX1 and LA levels were positively correlated(r=0.451,P<0.01)and they both negatively correlated with the Gensini score(r=-0.241 and-0.273,respectively;P<0.01).Compared with normal mice,ApoE-/-mice showed significantly increased lipid levels(P<0.01)and atherosclerosis index,obvious thickening,lipid aggregation,and collagen fiber hyperplasia in the aorta,and significantly reduced expressions of FDX1,LA,LIAS,and ACO2(P<0.05).Conclusion Serum FDX1 and LA levels decrease with worsening of coronary artery lesions,and theirs expressions are correlated with coronary artery lesions induced by hyperlipidemia.

Objective To investigate the effect of asiaticoside on blood pressure and relaxation of thoracic aorta in rats and explore the underlying mechanism.Methods SD rats treated with 50 and 100 mg/kg asiaticoside by daily gavage for 2 weeks were monitored for systolic blood pressure changes,and histological changes of the thoracic aorta were evaluated using HE staining.In isolated rat endothelium-intact and endothelium-denuded thoracic aorta rings,the effects of asiaticoside on relaxation of the aortic rings were tested at baseline and following norepinephrine(NE)-and KCl-induced constriction.The vascular relaxation effect of asiaticoside was further observed in NE-stimulated endothelium-intact rat aortic rings pretreated with L-nitroarginine methyl ester,indomethacin,zinc protoporphyrin Ⅸ,tetraethyl ammonium chloride,glibenclamide,barium chloride,Iberiotoxin,4-aminopyridine,or TASK-1-IN-1.The aortic rings were treated with KCl and NE followed by increasing concentrations of CaCl2 to investigate the effect of asiaticoside on vasoconstriction induced by external calcium influx and internal calcium release.Results Asiaticoside at 50 and 100 mg/kg significantly lowered systolic blood pressure in rats without affecting the thoracic aorta histomorphology.While not obviously affecting resting aortic rings with intact endothelium,asiaticoside at 100 mg/kg induced significant relaxation of the rings constricted by KCl and NE,but its effects differed between endothelium-intact and endothelium-denuded rings.In endothelium-intact aortic rings pretreated with indomethacin,ZnPP Ⅸ,barium chloride,glyburide,TASK-1-IN-1 and 4-aminopyridine,asiaticoside did not produce significant effect on NE-induced vasoconstriction,and tetraethylammonium,Iberiotoxin and L-nitroarginine methyl ester all inhibited the relaxation effect of asiaticoside.In KCl-and NE-treated rings,asiaticoside obviously inhibited CaCl2-induced vascular contraction.Conclusion Asiaticoside induces thoracic aorta relaxation by mediating high-conductance calcium-activated potassium channel opening,promoting nitric oxide release from endothelial cells and regulating Ca2+ influx and outflow,thereby reducing systolic blood pressure in rats.

Objective To explore the impact of diabetes on collateral circulation (CC) development in patients with chronic total coronary occlusion (CTO) and the underlying regulatory mechanism. Methods This study was conducted among 87 patients with coronary heart disease (CHD), who had CTO in at least one vessel as confirmed by coronary angiography. Among them 42 patients were found to have a low CC level (Cohen-Rentrop grades 0-1) and 45 had a high CC level (grades 2-3). In the 39 patients with comorbid diabetes mellitus and 48 non-diabetic patients, insulin resistance (IR) levels were compared between the subgroups with different CC levels. The steady-state mode evaluation method was employed for calculating the homeostatic model assessment for insulin resistance index (HOMA-IR) using a mathematical model. During the interventional procedures, collateral and peripheral blood samples were collected from 22 patients for comparison of the metabolites using non-targeted metabolomics analysis. Results NT-proBNP levels and LVEF differed significantly between the patients with different CC levels (P<0.05). In non-diabetic patients, HOMA-IR was higher in low CC level group than in high CC level groups. Compared with the non-diabetic patients, the diabetic patients showed 63 upregulated and 48 downregulated metabolites in the collateral blood and 23 upregulated and 14 downregulated metabolites in the peripheral blood. The differential metabolites in the collateral blood were involved in aromatic compound degradation, fatty acid biosynthesis, and steroid degradation pathways; those in the peripheral blood were related with pentose phosphate metabolism, bacterial chemotaxis, hexanoyl-CoA degradation, glycerophospholipid metabolism, and lysine degradation pathways. Conclusion The non-diabetic patients with a low level of CC had significant insulin resistance. The degradation pathways of aromatic compounds, fatty acid biosynthesis, and steroid degradation are closely correlated with the development of CC.

Objective To explore the effect of quercetin on renal inflammation and cell apoptosis in diabetic rats and its possible mechanisms.Methods Twenty-four adult male SD rats were randomized equally into normal control group,high-glucose and high-fat feeding group,streptozotocin(STZ)-induced diabetic model group,and quercetin treatment(daily dose 100 mg/kg)group.Pathological changes of the renal tissues of the rats were observed with HE staining,serum inflammatory factor levels were determined with ELISA,and renal expression of NF-κB was observed by immunohistochemistry.Fast blood glucose(FBG),serum levels of triglyceride(TG),BUN,and Scr,and 24-h urine protein content of the rats were measured,and renal expressions of HMGB1,RAGE,NF-κB,Bax,Bcl-2,and caspase-3 were detected with Western blotting.Results The diabetic rats showed significantly increased levels of FBG,TG,BUN,and Scr,renal hypertrophy index,24-h urinary protein content,serum IL-1β,IL-6 and TNF-α levels and renal expressions HMGB1,RAGE,NF-κB,Bax,and caspase-3 with decreased renal expression of Bcl-2.All these changes were significantly alleviated by quercetin treatment of the rats.Conclusion Quercetin can ameliorate kidney injury in diabetic rats possibly by inhibiting the HMGB1/RAGE/NF-κB inflammatory signaling pathway to reduce renal inflammation and renal cell apoptosis.

Objective To investigate whether activation of mitochondrial acetal dehydrogenase 2(ALDH2)alleviates hypoxic pulmonary hypertension by regulating the SIRT1/PGC-1α signaling pathway.Methods Thirty 8-week-old C57 BL/6 mice were randomized into control,hypoxia,and hypoxia+Alda-1(an ALDH2 activator)group(n=10),and the mice in the latter two groups,along with 10 ALDH2 knockout(ALDH2-/-)mice,were exposed to hypoxia(10%O2,90%N2)with or without daily intraperitoneal injection of Alda-1 for 4 weeks.The changes in right ventricular function and pressure(RVSP)of the mice were evaluated by echocardiography and right ventricular catheter test,and pulmonary artery pressure was estimated based on RVSP.Pulmonary vascular remodeling,right ventricular injury,myocardial α-SMA expression,distal pulmonary arteriole muscle normalization,right ventricular cross-sectional area,myocardial cell hypertrophy,and right cardiac hypertrophy index were assessed with HE staining,immunofluorescence staining and WGA staining,and the expressions of ALDH2,SIRT1,PGC-1α,P16INK4A and P21CIP1 were detected.In pulmonary artery smooth muscle cells with hypoxic exposure,the effect of Alda-1 and EX527 on cell senescence and protein expressions was evaluated using β-galactose staining and Western blotting.Results The wild-type mice with hypoxic exposure showed significantly increased RVSP,right ventricular free wall thickness and myocardial expressions of P16INK4A and P21CIP1,which were effectively lowered by treatment with Alda-1 but further increased in ALDH2-/-mice.In cultured pulmonary artery smooth muscle cells,hypoxic exposure significantly increased senescent cell percentage and cellular expressions of P16INK4A and P21CIP1,which were all lowered by treatment with Alda-1,but its effect was obviously attenuated by EX527 treatment.Conclusion ALDH2 alleviates hypoxia-induced senescence of pulmonary artery smooth muscle cells by upregulating the SIRT1/PGC-1α signaling pathway to alleviate pulmonary hypertension in mice.

Objective To analyze the correlation of copper death inducer ferredoxin 1(FDX1)and lipoic acid(LA)with the occurrence and severity of coronary atherosclerosis and explore their roles in coronary heart disease(CHD).Methods We analyzed the data of 226 patients undergoing coronary artery angiography(CAG)in our hospital between October,2021 and October,2022,including 47 patients with normal CAG findings(control group)and 179 patients with mild,moderate or severe coronary artery stenosis(CHD group).Serum FDX1 and LA levels were determined with ELISA for all the patients.We also examined pathological changes in the aorta of normal and ApoE-/-mice using HE staining and observed collagen fiber deposition with Sirius red staining.Immunohistochemistry was used to detect the expression and distribution of FDX1 and LA in the aorta,and RT-PCR was performed to detect the expressions of FDX1,LIAS and ACO2 mRNAs in the myocardial tissues.Results Compared with the control patients,CHD patients had significantly lower serum FDX1 and LA levels,which decreased progressively as coronary artery stenosis worsened(P<0.01)and as the number of involved coronary artery branches increased(P<0.05).Serum FDX1 and LA levels were positively correlated(r=0.451,P<0.01)and they both negatively correlated with the Gensini score(r=-0.241 and-0.273,respectively;P<0.01).Compared with normal mice,ApoE-/-mice showed significantly increased lipid levels(P<0.01)and atherosclerosis index,obvious thickening,lipid aggregation,and collagen fiber hyperplasia in the aorta,and significantly reduced expressions of FDX1,LA,LIAS,and ACO2(P<0.05).Conclusion Serum FDX1 and LA levels decrease with worsening of coronary artery lesions,and theirs expressions are correlated with coronary artery lesions induced by hyperlipidemia.

Objective To investigate the effect of asiaticoside on blood pressure and relaxation of thoracic aorta in rats and explore the underlying mechanism.Methods SD rats treated with 50 and 100 mg/kg asiaticoside by daily gavage for 2 weeks were monitored for systolic blood pressure changes,and histological changes of the thoracic aorta were evaluated using HE staining.In isolated rat endothelium-intact and endothelium-denuded thoracic aorta rings,the effects of asiaticoside on relaxation of the aortic rings were tested at baseline and following norepinephrine(NE)-and KCl-induced constriction.The vascular relaxation effect of asiaticoside was further observed in NE-stimulated endothelium-intact rat aortic rings pretreated with L-nitroarginine methyl ester,indomethacin,zinc protoporphyrin Ⅸ,tetraethyl ammonium chloride,glibenclamide,barium chloride,Iberiotoxin,4-aminopyridine,or TASK-1-IN-1.The aortic rings were treated with KCl and NE followed by increasing concentrations of CaCl2 to investigate the effect of asiaticoside on vasoconstriction induced by external calcium influx and internal calcium release.Results Asiaticoside at 50 and 100 mg/kg significantly lowered systolic blood pressure in rats without affecting the thoracic aorta histomorphology.While not obviously affecting resting aortic rings with intact endothelium,asiaticoside at 100 mg/kg induced significant relaxation of the rings constricted by KCl and NE,but its effects differed between endothelium-intact and endothelium-denuded rings.In endothelium-intact aortic rings pretreated with indomethacin,ZnPP Ⅸ,barium chloride,glyburide,TASK-1-IN-1 and 4-aminopyridine,asiaticoside did not produce significant effect on NE-induced vasoconstriction,and tetraethylammonium,Iberiotoxin and L-nitroarginine methyl ester all inhibited the relaxation effect of asiaticoside.In KCl-and NE-treated rings,asiaticoside obviously inhibited CaCl2-induced vascular contraction.Conclusion Asiaticoside induces thoracic aorta relaxation by mediating high-conductance calcium-activated potassium channel opening,promoting nitric oxide release from endothelial cells and regulating Ca2+ influx and outflow,thereby reducing systolic blood pressure in rats.

Objective To explore the impact of diabetes on collateral circulation (CC) development in patients with chronic total coronary occlusion (CTO) and the underlying regulatory mechanism. Methods This study was conducted among 87 patients with coronary heart disease (CHD), who had CTO in at least one vessel as confirmed by coronary angiography. Among them 42 patients were found to have a low CC level (Cohen-Rentrop grades 0-1) and 45 had a high CC level (grades 2-3). In the 39 patients with comorbid diabetes mellitus and 48 non-diabetic patients, insulin resistance (IR) levels were compared between the subgroups with different CC levels. The steady-state mode evaluation method was employed for calculating the homeostatic model assessment for insulin resistance index (HOMA-IR) using a mathematical model. During the interventional procedures, collateral and peripheral blood samples were collected from 22 patients for comparison of the metabolites using non-targeted metabolomics analysis. Results NT-proBNP levels and LVEF differed significantly between the patients with different CC levels (P<0.05). In non-diabetic patients, HOMA-IR was higher in low CC level group than in high CC level groups. Compared with the non-diabetic patients, the diabetic patients showed 63 upregulated and 48 downregulated metabolites in the collateral blood and 23 upregulated and 14 downregulated metabolites in the peripheral blood. The differential metabolites in the collateral blood were involved in aromatic compound degradation, fatty acid biosynthesis, and steroid degradation pathways; those in the peripheral blood were related with pentose phosphate metabolism, bacterial chemotaxis, hexanoyl-CoA degradation, glycerophospholipid metabolism, and lysine degradation pathways. Conclusion The non-diabetic patients with a low level of CC had significant insulin resistance. The degradation pathways of aromatic compounds, fatty acid biosynthesis, and steroid degradation are closely correlated with the development of CC.