Effect of docosahexaenoic acid on hypoxia/reoxygenation injury in human coronary arterial smooth muscle cells

HMGB1 induces apoptosis and EMT in association with increased autophagy following H/R injury in cardiomyocytes

Hypoxia/reoxygenation (H/R) is a critical factor in the pathogenesis of tissue injury following myocardial infarction (MI) which can lead to tissue damage and pathological remodeling. Therefore, it is necessary to try and prevent myocardial H/R injury in order to optimize the treatment of MI. This study aimed to explore the functions and molecular mechanisms of action of high mobility group box 1 (HMGB1) and its role in H/R injury to H9c2 cells. The mRNA expression of levels genes were detected by RT-qPCR. The protein levels were examined by western blot analysis. The Beclin 1 expression level was further determined by immunocytochemistry (ICC). In addition, an HMGB1 overexpression vector and a shRNA lentiviral vector were constructed in order to induce the overexpression and silencing of HMGB1, respectively. The apoptotic rate of the H9c2 cells was determined by flow cytometry. The expression of miR-210 was markedly increased following the exposure of the cells to H/R, thus indicating that the cell model of H/R injury was successfully established. In addition, an in vivo model of MI was also created using rats. The mRNA and protein level of HMGB1 was found to be upregulated in the myocardial tissue of the rats with MI and in the H9c2 cells subjected to H/R injury. HMGB1 promoted apoptosis by increasing the expression of cleaved caspase-3 and the apoptotic rate of the cells, while decreasing the expression of Bcl-2 during H/R in the H9c2 cells. HMGB1 promoted epithelial-to-mesenchymal transition (EMT) by reducing the protein level of the epithelial marker, E-cadherin, while increasing the expression of the mesenchymal markers, vimentin and fibroblast-specific protein (FSP), during H/R in the H9c2 cells. HMGB1 induced the apoptosis of the H9c2 cells and EMT following H/R in association with the induction of autophagy. HMGB1 induced autophagy by upregulating the expression of discoidin domain receptor 1 (DDR1) and downregulating the phosphorylation levels of mammalian target of rapamycin (mTOR). In conclusion, the findings of our study suggest that HMGB1 promotes apoptosis and EMT in association with the induction of autophagy through the upregulation of the expression of DDR1 and the downregulation of the phosphorylation of mTOR following H/R injury in H9c2 cells.

Combined Salvianolic Acid B and Ginsenoside Rg1 Exerts Cardioprotection against Ischemia/Reperfusion Injury in Rats

Lack of pharmacological strategies in clinics restricts the patient prognosis with myocardial ischemia/reperfusion (I/R) injury. The aim of this study was to evaluate the cardioprotection of combined salvianolic acid B (SalB) and ginsenoside Rg1 (Rg1) against myocardial I/R injury and further investigate the underlying mechanism. I/R injury was induced by coronary artery ligation for Wistar male rats and hypoxia/reoxygenation injury was induced on H9c2 cells. Firstly, the best ratio between SalB and Rg1was set as 2:5 based on their effects on heart function detected by hemodynamic measurement. Then SalB-Rg1 (2:5) was found to maintain mitochondrial membrane potential and resist apoptosis and necrosis in H9c2 cell with hypoxia/reoxygenation injury. Companying with same dose of SalB or Rg1 only, SalB-Rg1 showed more significant effects on down-regulation of myocardial infarct size, maintenance of myocardium structure, improvement on cardiac function, decrease of cytokine secretion including TNF-α, IL-1β, RANTES and sVCAM-1. Finally, the SalB-Rg1 improved the viability of cardiac myocytes other than cardiac fibroblasts in rats with I/R injury using flow cytometry. Our results revealed that SalB-Rg1 was a promising strategy to prevent myocardial I/R injury.

Protective effects of polyunsatutared fatty acids supplementation against testicular damage induced by intermittent hypobaric hypoxia in rats

BACKGROUND

Intermittent hypobaric hypoxia (IHH) induces changes in the redox status and structure in rat testis. These effects may be present in people at high altitudes, such as athletes and miners. Polyunsaturated fatty acids (PUFA) can be effective in counteracting these oxidative modifications due to their antioxidants properties. The aim of the work was to test whether PUFA supplementation attenuates oxidative damage in testis by reinforcing the antioxidant defense system. The animals were divided into four groups (7 rats per group): normobaric normoxia (~750 tor; pO2 156 mmHg; Nx); Nx + PUFA, supplemented with PUFA (DHA: EPA = 3:1; 0.3 g kg(-1) of body weight per day); hypoxic hypoxia (~428 tor; pO2 90 mmHg; Hx) and, Hx + PUFA. The hypoxic groups were exposed in 4 cycles to 96 h of HH followed by 96 h of normobaric normoxia for 32 days. Total antioxidant capacity (FRAP) and lipid peroxidation (malondialdehyde, MDA) in plasma and reduced (GSH)/oxidized glutathione (GSSG) ratio, tissue lipid peroxidation (TBARS) and antioxidant enzymes activity were assessed at the end of the study in testis. Also, SIRTUIN 1 and HIF-1 protein expression in testis were determined.

RESULTS

IHH increased lipid peroxidation in plasma and HIF-1 protein levels in testis. In addition, IHH reduced FRAP levels in plasma, antioxidant enzymes activities and SIRTUIN 1 protein levels in testis. PUFA supplementation attenuated these effects, inducing the increases in FRAP, in the antioxidant enzymes activity and HIF-1 levels.

CONCLUSIONS

These results suggest that the IHH model induces a prooxidant status in plasma and testis. The molecular protective effect of PUFA may involve the induction of an antioxidant mechanism.

Association of serum phospholipid PUFAs with cardiometabolic risk: beneficial effect of DHA on the suppression of vascular proliferation/inflammation

OBJECTIVES

Blood or dietary polyunsaturated fatty acids (PUFAs), particularly ω3-PUFAs were known for cardiovascular protective effect. However, the results are still controversial. We aimed to investigate the association of serum phospholipid PUFAs with cardiometabolic risk through cross-sectional/experimental studies.

DESIGN/METHODS

Serum phospholipid FA compositions and cardiometabolic risk parameters were measured in controls [healthy: n=987, metabolic syndrome (MetS): n=214] and CAD patients (CAD-only: n=152, CAD+MetS: n=56). Experimental assays were performed in vascular smooth muscle cells (VSMCs).

RESULTS

Major cardiometabolic risk markers, i.e. insulin resistance, hs-C-reactive proteins, and malondialdehyde were higher, and adiponectin and LDL particle size were lower in CAD patients, particularly those with MetS than in healthy controls. Serum linoleic acid (LA, C18:2ω-6) was lowest and dihomo-γ-linolenic acids (DGLAs, C20:3ω-6) were highest in CAD patients with MetS among the 4 groups. Docosahexaenoic acid (DHA, C22:6ω-3) was lower and arachidonic acid (AA, C20:4ω-6) and ω6/ω3-PUFAs were higher in CAD patients than in controls. ω3-PUFAs were significantly lower in CAD patients, particularly those with MetS than in healthy controls. Multiple regression analysis revealed that AA and DHA among serum FAs were mainly associated with the cardiometabolic risk (β'-coefficients for AA:0.336; DHA: -0.296) together with age, MetS factors, LA, DGLA and gender (r=0.529, p<0.001). Under LPS-induced stress condition, LA and DHA significantly suppressed VSMC proliferation. DHA also up-regulated the phosphorylation of p38 and ERK, and dramatically inhibited nuclear translocation of NF-κB-p65 in VSMCs.

CONCLUSION

AA and DHA were mainly associated with cardiometabolic risk. Particularly, DHA may be effective on suppression of vascular proliferation and inflammation.