Abstract:Aim To investigate the effect of alfentanil on myocardial ischemia-reperfusion injury (MIRI) in rats and its regulatory mechanism on the sphingosine kinase 1 (SphK1)/sphingosine-1-phosphate (S1P) signaling pathway during this process. Methods SPF grade SD male rats were randomly divided into sham surgery group, model group, positive drug group (compound salvia miltiorrhiza group), low dose alfentanil group, high dose alfentanil group, and high alfentanil+SphK1 agonist group (alfentanil+PMA group), with 20 rats in each group. Except the sham operation group, the MIRI model was reproduced by ligating the left anterior descending coronary artery and reperfusion. The activities of serum lactate dehydrogenase (LDH), creatine kinase (CK) and aspartate aminotransferase (AST) were detected by automatic biochemical analyzer; TTC was applied to detect the size of myocardial infarction in rats; HE staining was applied to observe the morphological characteristics of rat myocardial tissue; TUNEL staining was applied to detect myocardial cell apoptosis in rats; ELISA was applied to detect the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), and S1P; kits were applied to detect content of malondialdehyde (MDA) and activity of superoxide dismutase (SOD) in myocardial tissue; Western blot was applied to detect the expression level of SphK1 protein in myocardial tissue. Results Compared with the sham surgery group, the pathological damage to the myocardial tissue of rats was severe in the model group, the activities of serum central muscle injury markers LDH, CK, and AST, myocardial infarction area, myocardial cell apoptosis rate, the levels of TNF-α, IL-6, IL-1β, MDA, S1P and the expression of SphK1 protein all increased, the activity of SOD decreased (P＜0.05). Compared with the model group, the myocardial tissue damage of rats was reduced in the positive drug group and the low and high dose alfentanil groups, the activities of serum central muscle injury markers LDH, CK, and AST, myocardial infarction area, myocardial cell apoptosis rate, the levels of TNF-α, IL-6, IL-1β, MDA, S1P and the expression of SphK1 protein all decreased, the activity of SOD increased (P＜0.05). The SphK1 agonist was able to reverse the impact of high-dose alfentanil on the above indicators (P＜0.05). Conclusion Alfentanil has protective effect on MIRI rats, and its mechanism may be related to the inhibition of SphK1/S1P signaling pathway.

Abstract:Timely restoration of blood supply after myocardial infarction is crucial for saving the infarcted myocardium. So far, the most effective method is to restore myocardial oxygenation and coronary blood flow through coronary interventional therapy. However, reperfusion may also lead to greater heart damage due to the reintroduction of molecular oxygen. New treatments are needed to protect the heart from myocardial ischemia-reperfusion injury (MIRI) to improve clinical outcomes in patients with acute myocardial infarction and heart failure (HF). A deeper understanding of the mechanisms of MIRI and the search for new treatments could provide key evidence to mitigate myocardial damage and improve patient survival. At present, it has been found that copper, as a trace element in human body, can have a significant protective effect on MIRI. Copper can reduce apoptosis in cardiomyocytes, that is, control the self-destruction process of cell, so as to reduce the degree of myocardial injury. However, the potential relationship between abnormal copper ion metabolism as well as cuproptosis and MIRI as well as HF has not been explored. In this review, we focus on potential therapeutic strategies for MIRI and understand the metabolic pathways of copper in the human body, so as to provide more options and hope for the treatment of cardiovascular diseases.

Abstract:Myocardial ischemia-reperfusion injury (MIRI) is one of the reasons for the high mortality in patients with acute myocardial infarction after percutaneous coronary intervention, which is regulated by several cell death pathways including apoptosis, autophagy, and pyroptosis. Recently, it has been found that ferroptosis, a unique programmed cell death, appears to be a therapeutic target for MIRI. However, the mechanisms remain incompletely elucidated. This review summarizes the latest research progress on the role of ferroptosis in MIRI, including mitochondrial dysfunction, endoplasmic reticulum stress (ERS), oxidative stress, calcium overload, epigenetic modification, apoptosis, autophagy, etc. Moreover, the signaling pathways between ferroptosis and MIRI are elaborated, which will provide new insights for the prevention and treatment of MIRI.

Abstract:Myocardial ischemia-reperfusion injury (MIRI) is one of the main causes of high mortality in patients with myocardial infarction after active revascularization. It is of great significance to find effective intervention targets to alleviate MIRI and explore its protective mechanism. Cell pyroptosis is a form of inflammatory programmed cell death in addition to cell necrosis and apoptosis. In recent years, studies have found that pyroptosis is closely related to the occurrence and development of MIRI. This article reviews the pyroptosis and its mechanism of action in MIRI, and discusses the new research progress of small-molecule drugs, natural drugs and commonly used clinical drugs which affect cell pyroptosis and applied in the prevention and treatment of MIRI.

Abstract:Aim To investigate the effect of overexpression of Bax inhibitor-1(BI-1) gene in cardiomyocytes on ischemia-reperfusion injury and its mechanism. Methods Thirty SD rats were randomly divided into sham operation group (sham group), ischemia-reperfusion group (I/R group), adenovirus control group (Ad-EGFP group), overexpression of BI-1 genome group (Ad-BI-1 group), cyclosporine A group (CsA group). After the establishment of myocardial ischemia-reperfusion injury(MIRI)model in rats, TTC staining was used to observe myocardial infarction area, TUNEL staining was used to observe myocardial apoptosis, ultrastructural changes of myocardial cells were observed under electron microscope; qRT-PCR was used to detect the expression of BI-1 mRNA in the myocardium of rats in each group. The myocardial cells of neonatal rats were isolated and cultured and divided into control group, hypoxia/reoxygenation group (H/R group), adenovirus control group (Ad-EGFP group), overexpression of BI-1 genome group (Ad-BI-1 group) and cyclosporine A group (CsA group) according to different cell treatment. The subcellular localization of BI-1 was detected by immunocytochemistry, the expression of BI-1 protein was detected by Western blot, and the MPTP opening level of myocardial mitochondria was detected by Calcein-AM; and the expression of apoptosis related proteins Bcl-2, Bax, CytC, Caspase-3 and Caspase-9 were detected by Western blot. Results Compared with sham group, myocardial infarct area, apoptosis number, mitochondrial structure damage in I/R group, Ad-EGFP group, Ad-BI-1 group and CSA group increased significantly (P＜0.05), while those in Ad-BI-1 group and CsA group decreased significantly (P＜0.05) compared with I/R group. qRT-PCR results showed that compared with sham group, BI-1 mRNA expression decreased significantly in I/R group, Ad-EGFP group and CsA group, while it increased significantly in Ad-BI-1 group; Subcellular location showed that BI-1 was mainly located in the endoplasmic reticulum of cardiomyocytes, and the fluorescence intensity of Calcein-AM was significantly lower in H/R group, Ad-EGFP group, Ad-BI-1 and CsA group than that in control group, while that of Ad-BI-1 and CsA group was significantly higher than that of H/R group; Compared with control group, the expression level of BI-1 protein was significantly decreased in H/R group, Ad-EGFP group and CsA group, but it was significantly increased in Ad-BI-1 group. Western blot results showed that compared with sham group, the ratio of Bcl-2/Bax decreased significantly in I/R group, Ad-EGFP group, Ad-BI-1 group and CsA group (P＜0.05), the expression of Caspase-3 and Caspase-9 increased significantly (P＜0.05); while the ratio of Bcl-2/Bax increased significantly in Ad-BI-1 group and CsA group compared with I/R group (P＜0.05), and the expression of Caspase-3 and Caspase-9 decreased significantly (P＜0.05). The expression of CytC was significantly higher in I/R group, Ad-EGFP group, Ad-BI-1 group and CsA group than that of sham group (P＜0.05). However, the expression of CytC in the mitochondria of myocardial cells was significantly lower in I/R group, Ad-EGFP group, Ad-BI-1 group and CsA group than that of sham group (P＜0.05), and the expression of CytC was significantly higher in the Ad-BI-1 group and the CsA group than that of I/R group (P＜0.05). Conclusion Overexpression of BI-1 gene can reduce the myocardial infarct area of MIRI rats, reduce the apoptosis of myocardial cells and improve the mitochondrial structure and function damage. The mechanism may be that overexpression of BI-1 can play the above role by changing the Bcl-2/Bax ratio, inhibiting the opening of MPTP, reducing the release of CytC, and reducing the activation of Caspase-3 and Caspase-9.

Abstract:Aim To explore the improvement effects of Urocortin-I on myocardial monophasic action potential and oxidative inflammatory response in ischemia-reperfusion (I/R) myocardium by activatingAkt/GSK-3 β pathway. Methods Langendorff perfusion model of isolated myocardium was prepared and then divided into control group, I/R group, Urocortin-I group and Urocortin-I+LY group. The control group was given routine perfusion, I/R group was given routine preconditioning, Urocortin-I group was given Urocortin-I preconditioning, Urocortin-I+LY group was given Urocortin-I and LY2942 preconditioning before ischemia-reperfusion. The differences of myocardial enzymes, infarct size, monophasic action potential, inflammatory factors, oxidative stress products and Akt/GSK-3 β pathway molecules among the four groups were compared. Results Compared with the control group, the contents of LDH, CK-MB, TNF-α, IL-6, ICAM-1, ROS, MDA and the size of myocardial infarction significantly increased, while the levels of APA, APD50, APD90 and the expression of p-Akt, p-GSK-3β significantly decreased in the I/R group (P<0.05). Compared with the I/R group, the contents of LDH, CK-MB, TNF-α, IL-6, ICAM-1, ROS, MDA and the size of myocardial infarction significantly decreased, while the levels of APA, APD50, APD90 and the expressions of p-Akt, p-GSK-3β significantly increased in the Urocortin-I group (P<0.05). Compared with the Urocortin-I group, the contents of LDH, CK-MB, TNF-α, IL-6, ICAM-1, ROS, MDA and the size of myocardial infarction significantly increased, while the levels of APA, APD50, APD90 and the expressions of p-Akt, p-GSK-3β significantly decreased in the Urocortin-I+LYgroup (P<0.05).Conclusion Urocortin-I improves monophasic action potential and oxidative inflammation in I/R myocardium by activating Akt/GSK-3 β pathway.

Abstract:Myocardial infarction is one of the leading causes of death in patients with coronary heart disease worldwide. In the early stage of acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass grafting, drugs and other treatment means can restore the blood supply of ischemic myocardial tissue, save the dying myocardium and reduce the mortality rate of patients. However, after the interruption of myocardial blood supply and the restoration of blood supply within a certain period of time, the original ischemic myocardium may suffer more serious damage than that of ischemia. This phenomenon is called myocardial ischemia-reperfusion injury (MIRI), and its mechanism has not been fully elucidated. In this paper, the research progress of MIRI mechanism in recent years is reviewed, and the pathophysiological mechanism of MIRI is expounded, which will help to develop new therapeutic interventions and provide help for clinical treatment of myocardial infarction.

Abstract:Aim To explore whether Wenyang Tongmai decoction can regulate JAK2/STAT3 signal transduction pathway and the expression of aquaporins(AQP) to protect myocardial ischemia-reperfusion tissue. Methods Thirty male SD rats were randomly divided into 5 groups, 6 in each group:sham operation group, ischemia-reperfusion group, low-dose treatment group, middle-dose treatment group, high-dose treatment group. After 14 days of intragastric administration, the model of myocardial ischemia-reperfusion injury was established by ligation of the left anterior descending coronary artery for 30 minutes and then releasing the ligated artery for 120 minutes. The serum levels of creatine kinase isoenzymes (CK-MB) and lactate dehydrogenase (LDH) were detected by automatic biochemical analyzer. The ST-segment elevation of the rats was counted in the electrocardiogram. Pathological changes in cardiac tissue were observed by HE staining. The expressions of AQP1 and AQP4 in myocardial tissue were detected by immunohistochemical staining. The protein expressions of JAK2, p-JAK2, STAT3, p-STAT3, AQP1 and AQP4 were detected by Western blot method. Results Compared with the sham group, the levels of CK-MB and LDH in the serum of the ischemia-reperfusion group were significantly increased (P＜0.01), and the ST-segments of the electrocardiogram were significantly elevated after ischemia for 30 minutes and reperfusion for 120 minutes(P＜0.01). HE staining showed that the myocardial cells in the ischemia-reperfusion group were severely damaged. The expressions of AQP1 and AQP4 in immunohistochemistry was significantly increased (P＜0.01). The results of Western blot showed that the expressions of JAK2, p-JAK2, STAT3, p-STAT3, AQP1 and AQP4 were significantly increased (P＜0.01). Compared with the ischemia-reperfusion group, the serum levels of CK-MB and LDH were significantly decreased in the treated rats (P＜0.01), and the ST-segments were decreased after 30 minutes ischemia and 120 minutes reperfusion (P＜0.01), myocardial cells’ damage was alleviated to varying degrees in HE staining, the protein expressions of AQP1 and AQP4 in immunohistochemistry were significantly reduced, the expressions of JAK2, p-JAK2, STAT3 and p-STAT3 were generally increased, especially the expressions of p-JAK2 and p-STAT3 (P＜0.01), AQP1 and AQP4 expression levels were reduced to varying degrees(P＜0.01). Conclusion The cardioprotective effect of Wenyang Tongmai decoction may be related to activation of JAK2/STAT3 signaling pathway and down-regulation of AQP1 and AQP4 expression.

Abstract:Aim To investigate whether modified Zhishi Xiebai Guizhi decoction activates MitoKATP channel during myocardial ischemia-reperfusion to produce mitochondrial protection, thereby inhibiting mitochondrial apoptosis pathway and alleviating myocardial ischemia-reperfusion injury. Methods Twenty-four Sprague-Dawley rats were randomly divided into 3 groups:sham operation group (n=6), ischemia reperfusion model group (IR group, n=9), modified Zhishi Xiebai Guizhi decoction group (M group, n=9). After 14 days of administration, coronary artery anterior descending was performed. The model was established, and the ST segment of myocardial electrocardiogram, myocardial enzyme (CK-MB, LDH) and mitochondrial ultrastructural changes were observed. The myocardial infarct size of IR group and M group was compared by Evans blue/TTC staining. After rhodamine 123 staining, the mitochondrial membrane potential was detected by flow cytometry. The expressions of connexin43 (Cx43), protein kinase C-ε (PKC-ε) and inward-rectifier potassium channel 6.2 (Kir6.2) subunits in mitochondria of each group were detected by Western blot. Methylthymol blue microplate assay was used to detect calcium content in mitochondria of rats in each group. Results Modified Zhishi Xiebai Guizhi decoction can effectively alleviate ST segment and myocardial enzyme changes caused by myocardial ischemia-reperfusion, reduce myocardial infarct size, reduce mitochondrial ultrastructure and membrane potential changes, enhance the expression of Cx43, PKC-ε and Kir6.2 in mitochondrial and mitigating mitochondrial calcium overload. Conclusion Modified Zhishi Xiebai Guizhi decoction can activate MitoKATP channel to activate mitochondrial protective effect by up-regulating the expression of Cx43 and PKC-ε in mitochondria, thereby reducing the release of cytochrome C from mitochondria, inhibiting the cascade response of caspase-related proteins to reduce myocardial cells apoptosis rate, and to reduce myocardial ischemia-reperfusion injury.

Abstract:Aim To observe the protective effect of pioglitazone (PIO) on myocardial cell membrane in hyperlipemia rats with myocardial ischemia/reperfusion. Methods Establish hyperlipemia rat model and conduct intragastric administration with PIO. 4 weeks later, myocardial ischemia/reperfusion model was made on the basis of hyperlipemia. Then the myocardial cell membrane was separated through low temperature and high speed centrifugal preparation and the level of cholesterol(C), phospholipid (P) and the value of C/P and the activity of phospholipase A2(PLA2), the Na+-K+-ATPase, Mg2+-ATPase and Ca2+-ATPase were detected. Results ① At the end of the 4th week, the levels of serum triglycerides (TG), total cholesterol (TC) and high density lipoprotein cholesterol (HDLC) were significantly higher in hyperlipemia group than in control group (P＜0.05). At the 8th week, the levels of serum TG,TC were significantly lower in HL+PIO group than in HL group(P＜0.01 and P＜0.05). ② Myocardial membrane phospholipids in HL group were lower than in control group and HL+PIO group (P＜0.01 and P＜0.05). ③ The values of C/P in HL group were higher than in control group (P＜0.01) and HL+PIO group (P＜0.01). ④ The activity of PLA2 were higher in HL group(P＜0.05)and HL+PIO group(P＜0.05) than in control group. ⑤ Compared with the control group, the activity of Na+-K+-ATPase in HL group and Mg2+-ATPase in HL+PIO group differed respectively. Conclusion Pioglitazone protected myocardial cell membrane through maintaining the value of C/P, the activity of PLA2 and the activity of ion pump.