Study on the relationship of cPLA2, CK-MB, and membrane phospholipid content in acute myocardial infarction

Effects of maslinic acid on cardiac function in ischemia-reperfusion injury rats

Maslinic acid (MA), a pentacyclic triterpenoid, has been reported to exert broad pharmacological properties. However, it is still unclear whether MA exhibits protective effects against ischemia/reperfusion (I/R) injury. Herein, we aimed to investigate the effects of MA on I/R injury and its underlying mechanisms. A rat model of I/R injury was established and administrated with MA by intraperitoneal injection. Cardiac function was assessed with a color ultrasound diagnosis system and PowerLab system. The levels of oxidative stress-related and I/R-related biomarkers were evaluated by using commercial kits. Apoptosis-related biomarkers and sirtuin (SIRT)1/AMP-activated protein kinase (AMPK) signaling proteins were determined by using quantitative reverse transcription PCR and western blotting, respectively. Treatment with MA improved cardiac performance and cardiac hemodynamic parameters in the I/R injury rat model. Besides, treatment with MA (20 mg/kg) ameliorated I/R injury-related biomarkers in serum. Interestingly, treatment with MA (20 mg/kg) also regulated myocardial apoptosis and inhibited oxidative-stress in left ventricular tissue. Mechanistic studies demonstrated that MA upregulated SIRT1 and AMPK phosphorylation in the left ventricular tissue. In summary, MA exerted protective effects against the impairments of cardiac function in I/R injury rats by the regulation of SIRT1/AMPK signaling pathways.

UPLC-QTOF/MS-based metabolomics analysis of plasma reveals an effect of Xue-Fu-Zhu-Yu capsules on blood-stasis syndrome in CHD rats

ETHNOPHARMACOLOGICAL RELEVANCE

Blood-stasis syndrome (BSS) is a specific ZHENG type of coronary heart disease (CHD) in traditional Chinese medicine (TCM). The Xue-Fu-Zhu-Yu (XFZY) decoction is a common herbal formula that has been used for several centuries to treat BSS, but its mechanism has not been thoroughly elucidated to date.

AIM OF THE STUDY

In this study, serum lipid, blood haemorheology and metabolomics analyses were performed to depict a complete profile of XFZY capsules for the treatment of CHD with BSS and to reveal the potential mechanism of the XFZY capsules.

MATERIALS AND METHODS

A rat model of CHD with BSS was generated by combining a high-fat diet (HFD) with a left anterior descending coronary artery (LAD) ligation. After four weeks of treatment with XFZY capsules or simvastatin pills, an echocardiography was performed for a therapeutic evaluation. Blood samples and heart tissues were then collected for further analyses. A UPLC-QTOF/MS-based metabolomics analysis of the plasma was performed, and all metabolic features were fit by PCA and OPLS-DA pattern for the biomarker screen. The identified biomarkers were later implemented into a metabolic pathway analysis. Furthermore, we used qRT-PCR and Western blot analyses to verify the treatment effects of the XFZY capsules.

RESULTS

A total of 49 metabolites (VIP>1.0, p < 0.05, RSD%<20%) were identified in the Model rats, and 27 metabolites (VIP>1.0, p < 0.05, RSD%<20%) were identified in the XFZY-H rats. The results of the pathway analysis indicated that the XFZY capsules treated CHD primarily by regulating cardiac energy, phospholipid, polyunsaturated fatty acid (PUFA) and amino acid metabolism. In addition, blood viscosity and serum lipid assays suggested that XFZY capsules could decrease serum triglycerides, total cholesterol, low-density lipoprotein cholesterol and whole blood viscosity at a low shear rate.

CONCLUSION

This study demonstrated that the XFZY capsule effectively decreases serum lipids and whole blood viscosity in CHD with BSS. The underlying metabolic mechanism mainly included improving cardiac energy supply, reducing phospholipid peroxide, maintaining the PUFA metabolic balance and regulating amino acid metabolism.

Bio-tea prevents membrane destabilization during Isoproterenol-induced myocardial injury

The present study was undertaken to determine the membrane-stabilizing effect of Bio-tea in the prevention of myocardial injury caused by isoproterenol in rats. The efficiency of Bio-tea pretreatment was compared against black tea pretreatment and the positive control (rats with isoproterenol-induced myocardial infarction) and negative control (normal control rats). For this purpose, biochemical analysis of the in vivo antioxidants (superoxide dismutase, catalase, and reduced glutathione), glycoprotein components (hexose, hexosamine, sialic acid, and fucose), lipids (total, ester and free cholesterol, triglycerides, free fatty acids, and phospholipids), and transmembrane protein activities (Na+/K+ ATPase, Ca2+ ATPase, and Mg2+ ATPase) was carried out along with the histological and ultrastructural study of the myocardial tissue. Induction of myocardial infarction using isoproterenol resulted in a significant decrease in tissue antioxidants and an increase in the levels of total, ester and free cholesterol, triglycerides, free fatty acids, and glycoprotein components in plasma and heart. The phospholipid content showed an increase in plasma and a simultaneous decrease in the heart tissue, while the Na+/K+ ATPase activity decreased and Ca2+ ATPase and Mg2+ ATPase activities increased, resulting in destabilization of the membranes. Pretreatment with Bio-tea was able to bring these components to near normal, indicating its reactive-oxygen-species-scavenging, lipid-lowering, membrane-stabilizing and glycoprotein-modulating effects and lending credibility to the regular use of Bio-tea.

Cardioprotective effect of Salvianolic acid B on acute myocardial infarction by promoting autophagy and neovascularization and inhibiting apoptosis

OBJECTIVES

The aim of this study was to investigate the cardioprotective effect of salvianolic acid B (Sal B) on acute myocardial infarction (AMI) in rats and its potential mechanisms.

METHODS

The AMI model was established in rats to study the effect of Sal B on AMI. Haematoxylin-eosin (HE) staining was used to evaluate the pathological change in AMI rats. Immunofluorescence and TUNEL staining were used to detect autophagy and apoptosis of myocardial cells in hearts of AMI rats, respectively. Protein expression of apoptosis-related, autophagy-related and angiogenesis-related proteins were examined by Western blot.

KEY FINDINGS

Sal B attenuated myocardial infarction significantly compared with that of the model group. Rats administered with Sal B showed higher inhibition rate of infarction and lower infarct size than those of the model group. Moreover, Sal B decreased the serum levels of creatine kinase, lactate dehydrogenase and malondialdehyde, while increased such level of superoxide dismutase significantly compared with those of the model group. Sal B inhibited the expression of Bax, cleaved caspase-9 and cleaved PARP, while promoted the expression of Bcl-2, LC3-II, Beclin1 and VEGF.

CONCLUSIONS

Sal B has cardioprotective effect on AMI and Sal B may be a promising candidate for AMI treatment.

Window current through the T-type Ca2+ channel triggers the mechanism for cellular apoptosis via mitochondrial pathways

We hypothesized that Ca(2+) entry through the window T-type Ca(2+) current causes apoptosis. To test this hypothesis, we transfected human embryonic kidney (HEK) 293 cells to express recombinant Cav3.2 T-type Ca(2+) channels (hereafter called HEK-Cav3.2 cells). After incubation in media containing a high concentration (7.2 mM) of Ca(2+), intracellular Ca(2+) levels increased in HEK-Cav3.2 cells without electrical stimulation but not in untransfected HEK293 cells. In quiescent HEK-Cav3.2 cells exposed to high Ca(2+) media, apoptosis, as indicated by the appearance of hypodiploid cells, loss of mitochondrial transmembrane potential, and activation of caspases-3 and -9 was observed, while caspase-8 was not activated. These apoptosis-associated changes were blunted by pretreatment with the R(-)-isomer of efonidipine, a selective blocker of T-type Ca(2+) channels. High Ca(2+) did not induce apoptosis in untransfected HEK293 cells. Our findings show that Ca(2+) entry through the steady-state window current of T-type Ca(2+) channels causes apoptosis via mitochondrial pathways, and suggests that T-type Ca(2+) channels may be novel therapeutic targets for several diseases associated with abnormal apoptosis.