Capsaicin (Cap) has been reported to have beneficial effects on cardiovascular system, but the mechanisms underlying these effects are still poorly understood. Apoptosis has been shown to be involved in mitochondrial dysfunction, and upregulating expression of SIRT1 can inhibit the apoptosis of cardiomyocytes induced by anoxia/reoxygenation (A/R). Therefore, the aim of this study was to test whether the protective effects of Cap against the injury to the cardiomyocytes are mediated by SIRT1. The effects of Cap with or without coadministration of sirtinol, a SIRT1 inhibitor, on changes induced by A/R in the cell viability, activities of lactate dehydrogenase (LDH), creatine phosphokinase (CPK), levels of intracellular reactive oxygen species (ROS), and mitochondrial membrane potential (MMP), related protein expression, mitochondrial permeability transition pore (mPTP) opening, and apoptosis rate in the primary neonatal rat cardiomyocytes were tested. Cap significantly increased the cell viability, upregulated expression of SIRT1 and Bcl-2, and decreased the LDH and CPK release, generation of ROS, loss of MMP, mPTP openness, activities of caspase-3, release of the cytochrome c, and apoptosis of the cardiomyocytes. Sirtinol significantly blocked the cardioprotective effects of Cap. The results suggest that the protective effects of Cap against A/R-induced injury to the cardiomyocytes are involved with SIRT1.

Capsaicin(Cap) is an active component of chili peppers that is extracted from capsicum plants. Recent studies have reported that Cap can ameliorate myocardial ischemia/reperfusion(I/R) injury. Mitochondria play an important role in pathways of apoptosis induced by myocardial I/R injury. However, the underlying mechanisms of Cap that improve mitochondrial function during I/R injury is not yet understood. The aim of this study was to evaluate whether Cap regained normal mitochondrial function in myocardial I/R injury, and to further explore the underlying mechanisms of action involved. In this study, an acute myocardial anoxia/reoxygenation(A/R) injury model was established using H9c2 cells. The cell viability was detected by MTS assay. LDH activity, mitochondrial permeability transition pores(mPTP) opening, and caspase-3 activity were analyzed using an ultra violet spectrophotometer. Levels of intracellular reactive oxygen species and apoptosis were evaluated by flow cytometry. Western blot analysis was used to determine the expression of 14-3-3η, Bcl-2, and Bax. The data showed that pretreatment with Cap decreased LDH release and increased cell viability in H9c2 cells that underwent A/R. Cap pretreatment significantly attenuated generation of reactive oxygen species, inhibited mPTP opening and caspase-3 activation, downregulated Bax, upregulated 14-3-3η and Bcl-2, and ultimately reduced apoptosis in H9c2 cells that underwent A/R. Moreover, 14-3-3ηRNAi adenovirus markedly eliminated the protective effects of Cap in H9c2 cells that underwent A/R. In addition, ABT-737(inhibitor of Bcl-2) significantly eliminated Cap protection. Taken together, the present study suggested that the cardioprotective effect of Cap against A/R injury involves the 14-3-3η pathway and prevention of mitochondrial damage.

Tanshinone IIA is an important component that is isolated from danshen (Salvia miltiorrhiza), which is known to be beneficial for cardiovascular health. In this study, we determined the effects of Tanshinone IIA and its underlying mechanisms of action in an anoxia/reoxygenation (A/R) cell line model. Prior to inducing A/R injury, rat cardiomyocyte-derived cell line H9c2 was stimulated with 8 μM of Tanshinone IIA for 48 hours. When compared with the A/R group, the Tanshinone IIA treatment significantly increased cell viability and decreased lactate dehydrogenase activity. Tanshinone IIA upregulated 14-3-3η expression and facilitated Bcl-2 translocation to the mitochondrial outer membrane, which bound with voltage-dependent anion channel 1. In addition, pretreatment with Tanshinone IIA reduced the generation of reactive oxygen species and cytochrome c release, inactivated caspase-3, prevented mitochondrial permeability transition pore opening, and reduced the percentage of apoptotic cells. Moreover, treatment with Tanshinone IIA reduced the level of malondialdehyde, thereby increasing the activity of superoxide dismutase and glutathione peroxidase. Silencing the expression of 14-3-3η by adenovirus blocked the above-mentioned results. These novel findings showed that pretreatment with Tanshinone IIA alleviated H9c2 cell damage against A/R injury and was associated with upregulation of 14-3-3η, thereby facilitating Bcl-2 translocation to the mitochondrial outer membrane and preventing mitochondrial permeability transition pore opening, decreasing cytochrome c release, preventing caspase-3 activation, and restraining apoptosis.

Reactive oxygen species (ROS) are byproducts of a defective electron transport chain (ETC). The redox couples, GSH/GSSG and NAD+/NADH, play an essential role in physiology as internal defenses against excessive ROS generation by facilitating intracellular/mitochondrial (mt) redox homeostasis. Anoxia alone and anoxia/reoxygenation (A/R) are dissimilar pathological processes. In this study, we measured the impact of capsaicin (Cap) on these pathological processes using a primary cultured neonatal rat cardiomyocyte in vitro model. The results showed that overproduction of ROS was tightly associated with disturbed GSH/GSSG and NAD+/NADH suppressed mt complex I and III activities, decreased oxygen consumption rates, and elevated extracellular acidification rates. During anoxia or A/R period, these indices interact with each other causing the mitochondrial function to worsen. Cap protected cardiomyocytes against the different stages of A/R injury by rescuing NAD+/NADH, GSH/GSSG, and mt complex I/III activities and cellular energy metabolism. Importantly, Cap-mediated upregulation of 14-3-3η, a protective phosphoserine-binding protein in cardiomyocytes, ameliorated mt function caused by a disruptive redox status and an impaired ETC. In conclusion, redox pair, mt complex I/III, and metabolic equilibrium were significantly different in anoxia alone and A/R injury; Cap through upregulating 14-3-3η plays a protection against the above injury in cardiomyocyte.

Acute renal ischemia/reperfusion (I/R) injury often occurs during kidney transplantation and other kidney surgeries, and the molecular mechanism involves oxidative stress. We hypothesized that ginsenoside Rg1 (Rg1), a saponin derived from ginseng, would protect the renal tissue against acute renal I/R injury by upregulating 5' adenosine monophosphate-activated protein kinase α1 (AMPKα1) expression and inhibiting oxidative stress. The models of acute anoxia/reoxygenation (A/R) damage in normal rat kidney epithelial cell lines (NRK-52E) and acute renal I/R injury in mice were constructed. The results revealed that pretreatment with 25 μM Rg1 significantly increased NRK-52E viability, decreased lactate dehydrogenase (LDH) activity and apoptosis, suppressed reactive oxygen species generation and oxidative stress, stabilized mitochondrial membrane potential and reduced mitochondria permeability transition pore openness, decreased adenosine monophosphate/adenosine triphosphate ratio, and upregulated the expression of AMPKα1, cytochrome b-c1 complex subunit 2, NADH dehydrogenase (ubiquinone) 1 beta subcomplex subunit 8, and B-cell lymphoma 2, while downregulating BCL2-associated X protein expression. The effects of Rg1 pretreatment were similar to those of pAD/Flag-AMPKα1. After acute renal I/R injury, serum creatinine, blood urea nitrogen, LDH activity, and oxidative stress in renal tissue significantly increased. Rg1 pretreatment upregulated AMPKα1 expression, which protects against acute renal I/R injury by maintaining renal function homeostasis, inhibiting oxidative stress, and reducing apoptosis. Compound C, a specific inhibitor of AMPK, reversed the effects of Rg1. In summary, Rg1 pretreatment upregulated AMPKα1 expression, inhibited oxidative stress, maintained mitochondrial function, improved energy metabolism, reduced apoptosis, and ultimately protected renal tissue against acute renal I/R injury.

Vinegar is good for health. Tetramethylpyrazine (TMP) is the main component of its flavor, quality, and function. We hypothesized that vinegar/TMP pretreatment could induce myocardial protection of "nutritional preconditioning (NPC)" by low-dose, long-term supplementation and alleviate the myocardial injury caused by anoxia/reoxygenation (A/R). To test this hypothesis, TMP content in vinegar was detected by HPLC; A/R injury model was prepared by an isolated mouse heart and rat cardiomyocyte to evaluate the myocardial protection and mechanism of vinegar/TMP pretreatment by many enzymatic or functional, or cellular and molecular biological indexes. Our results showed that vinegar contained TMP, and its content was in direct proportion to storage time. Vinegar/TMP pretreatment could improve hemodynamic parameters, decrease lactate dehydrogenase (LDH) and creatine phosphokinase activities, and reduce infarct size and apoptosis in the isolated hearts of mice with A/R injury. Similarly, vinegar/TMP pretreatment could increase cell viability, decrease LDH activity, and decrease apoptosis against A/R injury of cardiomyocytes. Vinegar/TMP pretreatment could also maintain the mitochondrial function of A/R-injured cardiomyocytes, including improving oxygen consumption rate and extracellular acidification rate, reducing reactive oxygen species generation, mitochondrial membrane potential loss, mitochondrial permeability transition pore openness, and cytochrome c releasing. However, the protective effects of vinegar/TMP pretreatment were accompanied by the downregulation of VDAC1 expression in the myocardium and reversed by pAD/VDAC1, an adenovirus that upregulates VDAC1 expression. In conclusion, this study is the first to demonstrate that vinegar/TMP pretreatment could induce myocardial protection of NPC due to downregulating VDAC1 expression, inhibiting oxidative stress, and preventing mitochondrial dysfunction; that is, VDAC1 is their target, and the mitochondria are their target organelles. TMP is one of the most important myocardial protective substances in vinegar.