DL-3-n-butylphthalide improves the endothelium-dependent vasodilation in high-fat diet-fed ApoE-/- mice via suppressing inflammation, endothelial necroptosis and apoptosis.

Impaired endothelium-dependent vasodilation in atherosclerosis is a high-risk factor for myocardial infarction and ischemic stroke, and inflammation, necroptosis and apoptosis contribute to endothelial dysfunction in atherosclerosis. Although DL-3-n-butylphthalide (NBP) has been widely used in treating ischemic stroke, its effect on endothelium-dependent vasodilation remains unknown. This study aims to explore whether NBP is able to improve endothelium-dependent vasodilation in atherosclerosis and the underlying mechanisms. Male ApoE-/- mice were fed with a high-fat diet (HFD) for 9-16 weeks to establish a model of atherosclerosis. NBP were given to the mice after eating HFD for 6 weeks and atorvastatin served as a positive control. The endothelium-dependent vasodilation, the blood flow velocity, the atherosclerotic lesion area, the serum levels of lipids, inflammatory cytokines and necroptosis-relevant proteins (RIPK1, RIPK3 and MLKL), and the endothelial necroptosis and apoptosis within the aorta were measured. Human umbilical vein endothelial cells (HUVECs) were incubated with oxidized low-density lipoprotein (ox-LDL) for 48 h to mimic endothelial injury in atherosclerosis, lactate dehydrogenase release, the ratio of necroptosis and apoptosis and the expression of necroptosis-relevant proteins were examined. Similar to atorvastatin, NBP improves endothelium-dependent vasodilation, decreases aortic flow velocity and reduces atherosclerotic lesion area in HFD-fed ApoE-/- mice, concomitant with a reduction in serum lipids, inflammatory cytokines and necroptosis-relevant proteins, and endothelial necroptosis and apoptosis. Consistently, NBP inhibited necroptosis and apoptosis in ox-LDL-treated HUVECs. Based on these observations, we conclude that NBP exerts beneficial effects on improving the endothelium-dependent vasodilation in atherosclerosis via suppressing inflammation, endothelial necroptosis and apoptosis.

Inhibition of MALT1 reduces ferroptosis in rat hearts following ischemia/reperfusion via enhancing the Nrf2/SLC7A11 pathway.

The dysregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and/or solute carrier family 7 member 11 (SLC7A11) is believed to contribute to ferroptosis in the hearts suffered ischemia/reperfusion (I/R), but the mechanisms behind the dysregulation of them are not fully elucidated. Mucosa associated lymphoid tissue lymphoma translocation gene 1 (MALT1) can function as a paracaspase to cleave specified substrates and it is predicted to interact with Nrf2. This study aims to explore whether targeting MALT1 can reduce I/R-induced ferroptosis via enhancing the Nrf2/SLC7A11 pathway. The SD rat hearts were subjected to 1h-ischemia plus 3h-reperfusion to establish the I/R injury model, which showed myocardial injuries (increase in infarct size and creatine kinase release) and up-regulation of MALT1 while downregulation of Nrf2 and SLC7A11 concomitant with the increased ferroptosis, reflecting by an increase in glutathione peroxidase 4 (GPX4) level while decreases in the levels of acyl-CoA synthetase long chain family member 4 (ACSL4), total iron, Fe2+ and lipid peroxidation (LPO); these phenomena were reversed in the presence of MI-2, a specific inhibitor of MALT1. Consistently, similar results were achieved in the cultured cardiomyocytes subjected to 8h-hypoxia plus 12h-reoxygenation. Furthermore, micafungin, an antifungal drug, could also exert beneficial effect on mitigating myocardial I/R injury via inhibition of MALT1. Based on these observations, we conclud that inhibition of MALT1 can reduce I/R-induced myocardial ferroptosis through enhancing the Nrf2/SLC7A11 pathway; and MALT1 may be used as a potential target to seek novel or existing drugs (such as micafungin) for treating myocardial infarction.

Vascular peroxidase 1 promotes phenotypic transformation of pulmonary artery smooth muscle cells via ERK pathway in hypoxia-induced pulmonary hypertensive rats.

AIMS: Vascular peroxidase 1 (VPO1) plays an important role in mediation of vascular remodeling with pulmonary arterial hypertension (PAH). This study aims to determine whether VPO1 can promote phenotypic transformation of pulmonary artery smooth muscle cells (PASMCs) and the underlying mechanisms. MAIN METHODS: Sprague-Dawley (SD) rats were exposed to 10 % O2 for 21 days to establish the model of vascular remodeling in pulmonary arterial hypertension. PASMCs were incubated with 3 % O2 for 48 h to induce phenotypic transformation. Western blot was performed to detect the expressions of target proteins. The 5-ethynyl-2'-deoxyuridine (EdU) assay was conducted to measure the proliferation of PASMCs. KEY FINDINGS: In the rats exposed to hypoxia, there were increases in right ventricular systolic pressure, pulmonary vascular remodeling and phenotypic transformation of PASMCs (the down-regulated contractile proteins of α-smooth muscle actin, smooth muscle 22α while the up-regulated synthetic proteins of osteopontin, cyclinD1), accompanied by up-regulation of VPO1, increase of hypochlorous acid (HOCl) production and elevation of the phosphorylation of ERK. In the cultured PASMCs exposed to hypoxia, similar results were achieved but they were reversed by VPO1 small interfering RNA (VPO1 siRNA) or HOCl inhibitor. Replacement of hypoxia with NaOCl could induce PASMCs phenotypic transformation and activate the ERK signaling. Furthermore, ERK inhibitor (PD98059) could also attenuate hypoxia-induced PASMCs phenotypic transformation. SIGNIFICANCE: VPO1 play a pivotal role in promotion of phenotypic transformation of PASMCs under hypoxic condition through activation of VPO1/HOCl/ERK pathway. It might serve as a potential target for prevention of pulmonary vascular remodeling.

Involvement of miR-199a-3p/DDR1 in vascular endothelial cell senescence in diabetes.

Endothelial cell dysfunction is a prominent feature of diabetic cardiovascular complications, and endothelial cell senescence is considered to be an important contributor to endothelial dysfunction. Discoidin domain receptor 1 (DDR1) has been reported to be involved in atherogenesis and cerebral ischemia/reperfusion injury. In this study, we aimed to explore the role of DDR1 in endothelial cell senescence under diabetic conditions and elucidate the underlying mechanisms. A diabetic rat model was established by a single intraperitoneal injection of streptozocin (STZ) (60 mg/kg), which showed an increase in senescence-associated ß-galactosidase (SA-ß-gal) staining signal of thoracic aortic endothelium, impaired vascular structure and function, accompanied by an up-regulation of DDR1. Next, we verified the role of DDR1 in endothelial senescence and the underlying mechanisms in high glucose-treated human umbilical vein endothelial cells (HUVECs). Consistent with the in vivo findings, high glucose induced endothelial senescence, impaired endothelial function and elevated DDR1 expression, accompanied by the elevation of senescence-related genes p53 and p21 expression, and these effects were reversed by DDR1 siRNA. DDR1 has been documented to be a potential target of miR-199a-3p. Here, we found that miR-199a-3p was down-regulated by high glucose in the aorta tissue and HUVECs, while miR-199a-3p mimic significantly suppressed increased endothelial senescence and elevated DDR1 induced by high glucose. In conclusion, our data demonstrated that miR-199a-3p/DDR1/p53/p21 signaling pathway was involved in endothelial senescence under diabetic conditions, and therapeutic targeting DDR1 would be exploited to inhibit endothelial senescence owing to high glucose exposure.

Allopurinol attenuates oxidative injury in rat hearts suffered ischemia/reperfusion via suppressing the xanthine oxidase/vascular peroxidase 1 pathway.

Allopurinol, a xanthine oxidase (XO) inhibitor, is reported to alleviate myocardial ischemia/reperfusion (I/R) injury by reducing the production of reactive oxygen species (ROS). As an XO-derived product, H2O2 can act as a substrate of vascular peroxidase 1 (VPO1) to induce the generation of hypochlorous acid (HOCl), a potent oxidant. This study aims to explore whether the XO/VPO1 pathway is involved in the anti-oxidative effects of allopurinol on the myocardial I/R injury. In a rat heart model of I/R, allopurinol alleviated I/R oxidative injury accompanied by decreased XO activity, XO-derived products (H2O2 and uric acid), and VPO1 expression (mRNA and protein). In a cardiac cell model of hypoxia/reoxygenation (H/R), allopurinol or XO siRNA reduced H/R injury concomitant with decreased XO activity, VPO1 expression as well as the XO and VPO1-derived products (H2O2, uric acid, and HOCl). Although knockdown of VPO1 could also exert a beneficial effect on H/R injury, it did not affect XO activity, XO expression, and XO-derived products. Based on these observations, we conclude that the novel pathway of XO/VPO1 is responsible for, at least partly, myocardial I/R-induced oxidative injury, and allopurinol exerted the cardioprotective effects on myocardial I/R injury via inhibiting the XO/VPO1 pathway.

Ferroptosis occurs in phase of reperfusion but not ischemia in rat heart following ischemia or ischemia/reperfusion.

Ferroptosis is an iron-dependent regulated necrosis. This study aims to evaluate the contribution of ferroptosis to ischemia or reperfusion injury, and lay a basis for precise therapy of myocardial infarction. The Sprague-Dawley (SD) rat hearts were subjected to ischemia for different duration or the hearts were treated with 1 h-ischemia plus different duration of reperfusion. The myocardial injury was assessed by biochemical assays and hematoxylin & eosin (HE) staining. The ferroptosis was evaluated with the levels of acyl-CoA synthetase long-chain family member 4 (ACSL4), glutathione peroxidase 4 (GPX4), iron, and malondialdehyde. Iron chelator (deferoxamine) was applied to verify the contribution of ferroptosis to ischemia and reperfusion injury. The results showed that ischemic injury (infarction and CK release) was getting worse with the extension of ischemia, but no significant changes in ferroptosis indexes (ACSL4, GPX4, iron, and malondialdehyde) in cardiac tissues were observed. Differently, the levels of ACSL4, iron, and malondialdehyde were gradually elevated with the extension of reperfusion concomitant with a decrease of GPX4 level. In the ischemia-treated rat hearts, no significant changes in myocardial injury were observed in the presence of deferoxamine, while in the ischemia/reperfusion-treated rat hearts, myocardial injury was markedly attenuated in the presence of deferoxamine concomitant with a reduction of ferroptosis. Based on these observations, we conclude that ferroptosis occurs mainly in the phase of myocardial reperfusion but not ischemia. Thus, intervention of ferroptosis exerts beneficial effects on reperfusion injury but not ischemic injury, laying a basis for precise therapy for patients with myocardial infarction.

Ubiquitin-specific protease 7 promotes ferroptosis via activation of the p53/TfR1 pathway in the rat hearts after ischemia/reperfusion.

Iron overload triggers the ferroptosis in the heart following ischemia/reperfusion (I/R) and transferrin receptor 1 (TfR1) charges the cellular iron uptake. Bioinformatics analysis shows that the three molecules of ubiquitin-specific protease 7 (USP7), p53 and TfR1 form a unique pathway of USP7/p53/TfR1. This study aims to explore whether USP7/p53/TfR1 pathway promotes ferroptosis in rat hearts suffered I/R and the underlying mechanisms. The SD rat hearts were subjected to 1 h-ischemia plus 3 h-reperfusion, showing myocardial injury (increase in creatine kinase release, infarct size, myocardial fiber loss and disarray) and up-regulation of USP7, p53 and TfR1 concomitant with an increase of ferroptosis (reflecting by accumulation of iron and lipid peroxidation while decrease of glutathione peroxidase activity). Inhibition of USP7 activated p53 via suppressing deubiquitination, which led to down-regulation of TfR1, accompanied by the decreased ferroptosis and myocardial I/R injury. Next, H9c2 cells underwent hypoxia/reoxygenation (H/R) in vitro to mimic the myocardial I/R model in vivo. Consistent with the results in vivo, inhibition or knockdown of USP7 reduced the H/R injury (decrease of LDH release and necrosis) and enhanced the ubiquitination of p53 along with the decreased levels of p53 and TfR1 as well as the attenuated ferroptosis (manifesting as the decreased iron content and lipid peroxidation while the increased GPX activity). Knockdown of TfR1 inhibited H/R-induced ferroptosis without p53 deubiquitination. Based on these observations, we conclude that a novel pathway of USP7/p53/TfR1 has been identified in the I/R-treated rat hearts, where up-regulation of USP7promotes ferrptosis via activation of the p53/TfR1 pathway.

Arctiin protects rat heart against ischemia/reperfusion injury via a mechanism involving reduction of necroptosis.

RIPK1/RIPK3/MLKL (Receptor-interacting protein kinase 1/Receptor-interacting protein kinase 3/Mixed lineage kinase domain-like protein) pathway-mediated necroptosis contributes to myocardial ischemia/reperfusion (I/R) injury, and Arctiin can prevent myocardial fibrosis and hypertrophy. This study aims to explore the effect of Arctiin on myocardial I/R injury and the underlying mechanisms. SD rat hearts or cardiomyocytes were subjected to I/R or hypoxia/reoxygenation (H/R) to establish the I/R or H/R injury model. The methods of biochemistry, PI/DAPI (propidium iodide/4',6-Diamidino-2-Phenylindole) and H&E (Hematoxylin & eosin) staining were used to evaluate the I/R or H/R injury. The effects of Arctiin on necroptosis in I/R-treated hearts or H/R-treated cardiomyocytes were assessed. The results showed that Arctiin reduced myocardial I/R injury (decreases in myocardial infarction and creatine kinase release), concomitant with a decrease in levels of necroptosis-associated proteins (RIPK1/p-RIPK1, RIPK3/p-RIPK3 and MLKL/p-MLKL) in I/R-treated rat hearts. Consistently, the necrosis and LDH release in H/R-treated cardiomyocytes were attenuated in the presence of Arctiin, accompanied by suppression of necroptosis-relevant proteins. Furthermore, H/R-induced reactive oxygen species (ROS) generation and mitochondrial dysfunctions (increase in mitochondrial membrane potential and decrease in ATP production) were impaired by Arctiin. Using the program of the Molecular Operating Environment (MOE), we predict that RIPK1 and MLKL (but not RIPK3) might be the potential targets of Arctiin. Based on these observations, we conclude that Arctiin can protect the rat heart from I/R injury, and its beneficial effect is related to reduction of necroptosis via scavenging reactive oxygen species and restoring mitochondrial functions or targeting RIPK1 and/or MLKL.

Upregulation of mitochondrial E3 ubiquitin ligase 1 in rat heart contributes to ischemia/reperfusion injury.

Mitochondrial dysfunctions are responsible for myocardial injury upon ischemia/reperfusion (I/R), and mitochondrial E3 ubiquitin ligase 1 (Mul1) plays an important role in maintaining mitochondrial functions. This study aims to explore the function of Mul1 in myocardial I/R injury and the underlying mechanisms. The Sprague-Dawley rat hearts were subjected to 1 h of ischemia plus 3 h of reperfusion, which showed the I/R injury (increase in infarct size and creatine kinase release) and the elevated total and mitochondrial protein levels of Mul1 and p53 accompanied by the enhanced interactions between Mul1 and p53 as well as p53 and small a ubiquitin-like modifier (SUMO1). Consistently, hypoxia/reoxygenation (H/R) treated cardiac (H9c2) cells displayed cellular injury (apoptosis and necrosis), upregulation of total and mitochondrial protein levels of Mul1 and p53, and enhanced interactions between p53 and SUMO1 concomitant with mitochondrial dysfunctions (an increase in mitochondrial membrane potential and reactive oxygen species production with a decrease in ATP production); these phenomena were attenuated by knockdown of Mul1 expression. Based on these observations, we conclude that a novel role of Mul1 has been identified in the myocardial mitochondria, where Mul1 stabilizes and activates p53 through its function of SUMOylation following I/R, leading to p53-mediated mitochondrial dysfunction and cell death.

Mitochondrial E3 ubiquitin ligase 1 promotes brain injury by disturbing mitochondrial dynamics in a rat model of ischemic stroke.

Mitochondrial dysfunctions contribute to brain injury in ischemic stroke while disturbance of mitochondrial dynamics results in mitochondrial dysfunction. Mitochondrial E3 ubiquitin ligase 1 (Mul1) involves in regulation of mitochondrial fission and fusion. This study aims to explore whether Mul1 contributes to brain injury in ischemic stroke and the underlying mechanisms. First, a rat ischemic stroke model was established by middle cerebral artery occlusion (MCAO), which showed ischemic injuries (increase in neurological deficit score and infarct volume) and upregulation of Mul1 in brain tissues. Next, Mul1 siRNAs were injected intracerebroventricularly to knockdown Mul1 expression, which evidently attenuated brain injuries (decrease in neurological deficit score, infarct volume and caspase-3 activity), restored mitochondrial dynamics and functions (decreases in mitochondrial fission and cytochrome c release while increase in ATP production), and restored protein levels of dynamin-related protein 1 (Drp1, a mitochondrial fission protein) and mitofusin2 (Mfn2, a mitochondrial fusion protein) through suppressing their sumoylation and ubiquitination, respectively. Finally, PC12 cells were cultured under hypoxic condition to mimic the ischemic stroke. Consistently, knockdown of Mul1 significantly reduced hypoxic injuries (decrease in apoptosis and LDH release), restored protein levels of Drp1 and Mfn2, recovered mitochondrial dynamics and functions (decreases in mitochondrial fission, mitochondrial membrane potential, reactive oxygen species production and cytochrome c release while increase in ATP production). Based on these observations, we conclude that upregulation of Mul1 contributes to brain injury in ischemic stroke rats and disturbs mitochondrial dynamics through sumoylation of Drp1 and ubiquitination of Mfn2.

Magnesium Lithospermate B Derived from Salvia miltiorrhiza Ameliorates Right Ventricle Remodeling in Pulmonary Hypertensive Rats via Inhibition of NOX/VPO1 Pathway.

Right ventricle (RV) remodeling is a major pathological feature in pulmonary arterial hypertension (PAH). Magnesium lithospermate B (MLB) is a compound isolated from the roots of Salvia miltiorrhiza and it possesses multiple pharmacological activities such as anti-inflammation and antioxidation. This study aims to investigate whether MLB is able to prevent RV remodeling in PAH and the underlying mechanisms. In vivo, SD rats were exposed to 10% O2 for 21 d to induce RV remodeling, which showed hypertrophic features (increases in the ratio of RV weight to tibia length, cellular size, and hypertrophic marker expression), accompanied by upregulation in expression of NADPH oxidases (NOX2 and NOX4) and vascular peroxidase 1 (VPO1), increases in hydrogen peroxide (H2O2) and hypochlorous acid (HOCl) production and elevation in phosphorylation levels of ERK; these changes were attenuated by treating rats with MLB. In vitro, the cultured H9c2 cells were exposed to 3% O2 for 24 h to induce hypertrophy, which showed hypertrophic features (increases in cellular size and hypertrophic marker expression). Administration of MLB or VAS2870 (a positive control for NOX inhibitor) could prevent cardiomyocyte hypertrophy concomitant with decreases in NOX (NOX2 and NOX4) and VPO1 expression, H2O2 and HOCl production, and ERK phosphorylation. Based on these observations, we conclude that MLB is able to prevent RV remodeling in hypoxic PAH rats through a mechanism involving a suppression of NOX/VPO1 pathway as well as ERK signaling pathway. MLB may possess the potential clinical value for PAH therapy.

Inhibition of Phosphoglycerate Mutase 5 Reduces Necroptosis in Rat Hearts Following Ischemia/Reperfusion Through Suppression of Dynamin-Related Protein 1.

PURPOSE: Necroptosis is an important form of cell death following myocardial ischemia/reperfusion (I/R) and phosphoglycerate mutase 5 (PGAM5) functions as the convergent point for multiple necrosis pathways. This study aims to investigate whether inhibition of PGAM5 could reduce I/R-induced myocardial necroptosis and the underlying mechanisms. METHODS: The SD rat hearts (or H9c2 cells) were subjected to 1-h ischemia (or 10-h hypoxia) plus 3-h reperfusion (or 4-h reoxygenation) to establish the I/R (or H/R) injury model. The myocardial injury was assessed by the methods of biochemistry, H&E (hematoxylin and eosin), and PI/DAPI (propidium iodide/4',6-diamidino-2-phenylindole) staining, respectively. Drug interventions or gene knockdown was used to verify the role of PGAM5 in I/R (or H/R)-induced myocardial necroptosis and possible mechanisms. RESULTS: The I/R-treated heart showed the injuries (increase in infarct size and creatine kinase release), upregulation of PGAM5, dynamin-related protein 1 (Drp1), p-Drp1-S616, and necroptosis-relevant proteins (RIPK1/RIPK3, receptor-interacting protein kinase 1/3; MLKL, mixed lineage kinase domain-like); these phenomena were attenuated by inhibition of PGAM5 or RIPK1. In H9c2 cells, H/R treatment elevated the levels of PGAM5, RIPK1, RIPK3, MLKL, Drp1, and p-Drp1-S616 and induced mitochondrial dysfunctions (elevation in mitochondrial membrane potential and ROS level) and cellular necrosis (increase in LDH release and the ratio of PI+/DAPI+ cells); these effects were blocked by inhibition or knockdown of PGAM5. CONCLUSIONS: Inhibition of PGAM5 can reduce necroptosis in I/R-treated rat hearts through suppression of Drp1; there is a positive feedback between RIPK1 and PGAM5, and PGAM5 might serve as a novel therapeutic target for prevention of myocardial I/R injury.

Magnesium lithospermate B prevents phenotypic transformation of pulmonary arteries in rats with hypoxic pulmonary hypertension through suppression of NADPH oxidase.

Magnesium lithospermate B (MLB) shows multiple biological activities including anti-oxidation and anti-proliferation in various diseases. However, the function of MLB in pulmonary arterial hypertension (PAH) is still unknown. This study aims to investigate the effect of MLB on hypoxia-induced phenotypic transformation of pulmonary arterial smooth muscle cells (PASMCs) and the underlying mechanisms. SD rats (or PASMCs) were exposed to 10% O2 for 3 weeks (or 3% O2 for 48 h) along with MLB or NADPH oxidase （NOX） inhibitor intervention. The effects of MLB on hemodynamics, pulmonary vascular remodeling and phenotypic transformation of PASMCs were observed first. Then, its effects on the protein levels of NOX (NOX2 and NOX4), ERK and p-ERK were examined. The results showed that MLB prevented the elevation in right ventricular systolic pressure and the increase in ratio of wall thickness to vessel external diameter of pulmonary arteries in PAH rats, and attenuated phenotypic transformation of PASMCs (decrease in α-smooth muscle actin while increase in osteopontin), accompanied by downregulation of NOX (NOX2 and NOX4) protein levels, decrease of ROS and H2O2 production, and suppression of the phosphorylation of ERK. NOX inhibitor (VAS2870) achieved similar results to that of MLB did in the hypoxia-treated PASMCs. Based on the observations, we conclude that MLB is able to prevent phenotypic transformation of pulmonary arteries in hypoxic PAH rats through suppression of NOX/ROS/ERK pathway, and MLB might have the potentials in PAH therapy.

Asymmetric dimethylarginine contributes to retinal neovascularization of diabetic retinopathy through EphrinB2 pathway.

Diabetic retinopathy (DR) is a leading cause of vision loss with retinal neovascularization. This study aims to investigate whether Asymmetric dimethylarginine (ADMA) impacts the pathogenesis of DR via focusing on promoting retinal neovascularization and its underlying molecular mechanisms. Diabetic rats were induced by a single intraperitoneal injection of streptozotocin (STZ) for 20 weeks. ADMA levels in aqueous and the influence of hypoxia on ADMA and angiogenesis in RF/6A cells were examined. The effects and underlying molecular mechanisms of ADMA on neovascularization of RF/6A cells were further evaluated by administration of ADMA, DDAH siRNA or ephrinB2 siRNA. Results showed that ADMA levels were elevated in both aqueous from diabetic rats and culture medium in RF/6A cells pretreated with hypoxia. Administration of ADMA directly promoted proliferation, migration, adhesion and tube formation of RF/6A cells, which was further confirmed by DDAH1 siRNA or DDAH2 siRNA. In addition, ephrinB2 expression was increased under diabetic conditions, and the angiogenic effects of ADMA were blocked by ephrinB2 siRNA. In conclusion, ADMA contributes to the neovascularization of retina in diabetic mellitus, which is regulated by ephrinB2.

[Protective effect of Dendrobium candidum on isoproterenol induced cardiac hypertrophy in rats].

To study the effect and mechanism of Dendrobium candidum on isoproterenol-induced myocardial hypertrophy in rats, 60 healthy SD rats(30 males and 30 females) were randomly divided into 5 groups(12 in each group): normal group, model group, three D. candidum preventive administration groups(0.09, 0.18, 1.1 g·kg⁻¹). Except for the normal group, rats of other groups were injected back subcutaneously with ISO(5 mg·kg⁻¹) for 10 consecutive days. At the same time, preventive administration groups began to give different doses of the sample for 30 days and model group began to give normal saline. Left ventricular systolic pressure(LVSP) was measured in each group by common carotid artery cannulation, and the left ventricle(LW)/tibia length, heart weight index(HWI) and myocardial hydroxyproline(Hydro) content were calculated. Myocardial tissue HE staining and Masson staining were used to observe the myocardial structure and the degree of myocardial fibrosis respectively. Atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), and cardiac troponin I(cTN-I) concentration were measured by enzyme-linked immunosorbent assay(ELISA). The results showed that as compared with the normal group, the levels of ANP, BNP and cTN-I in plasma were significantly increased in ISO-induced hypertrophic rats; as compared with the model group, D. candidumcan inhibit ISO-induced ventricular pressure and ventricular hypertrophy, reduce myocardial collagen synthesis, improve myocardial fibrosis and ventricular remodeling, and significantly down-regulate ANP, BNP and cTN-I levels in plasma. This study shows that D. candidum has a protective effect on isoproterenol-induced cardiac hypertrophy.

Fasudil ameliorates the ischemia/reperfusion oxidative injury in rat hearts through suppression of myosin regulatory light chain/NADPH oxidase 2 pathway.

Fasudil is a potent Rho-kinase (ROCK) inhibitor and can relax smooth muscle or cardiac muscle contraction through decreasing the phosphorylation level of myosin regulatory light chain (p-MLC20 or p-MLC2v), while p-MLC2v can function as a transcription factor to promote the NADPH oxidase 2 (NOX2) expression in rat hearts subjected to ischemia/reperfusion (I/R). This study aims to explore whether fasudil can protect the rat hearts against I/R oxidative injury through suppressing NOX2 expression via reduction of p-MLC2v level. The SD rat hearts were subjected to 1h-ischemia plus 3h-reperfusion, which showed myocardial injuries (myocardial fiber loss and disarray, increase of creatine kinase release and myocardial infarction/apoptosis), increase in ROCK activity and nuclear p-MLC2v level concomitant with up-regulation of NOX2 and H2O2 production; these phenomena were attenuated by fasudil in a dose-dependent manner. Next, we verified the cardioprotective effect of fasudil and the underlying mechanisms in hypoxia-reoxygenation (H/R) -treated H9c2 cells. Consistent with the results in vivo, the H/R-treated H9c2 cells showed cellular injury (increase in apoptotic ratio), elevation in ROCK activity and nuclear p-MLC2v level, accompanied by up-regulation of NOX2 and H2O2 production; these effects were blocked in the presence of fasudil in a dose-dependent way. Based on these observations, we conclude that beneficial effect of fasudil against myocardial I/R or H/R oxidative injury is related to the suppression of NOX2 expression through decrease of the p-MLC2v level. Our findings also highlight that intervention of MLC2v phosphorylation by drugs may provide a novel strategy to protect heart from I/R oxidative injury.

Atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats through a mechanism involving down-regulation of miR-21-5p/203a-3p.

Statins are reported to exert benefits on endothelial function through a mechanism involving in prevention of endothelial senescence. This study aims to explore whether atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats or ox-LDL-treated HUVECs through a mechanism involving suppress of miR-21-5p/203a-3p expression and their downstream pathway. The rats were fed with high-fat diet to establish a hyperlipidemic model, which showed an increase in plasma lipids and endothelial senescence, accompanied by the elevation in plasma levels of miR-21-5p/203a-3p, down-regulation of Drp1 and up-regulation of p53 in the aorta of hyperlipidemic rats; these phenomena were reversed by atorvastatin. Next, HUVECs were incubated with ox-LDL to establish a senescent model in vitro. Consistent with the finding in vivo, atorvastatin treatment decreased the level of miR-21-5p and miR-203a-3p in the ox-LDL-treated HUVECs, restored Drp1 expression and mitochondrial function, as well as suppressed p53 and p16 expression and endothelial senescence. Based on these observations, we conclude that atorvastatin exerts inhibitory effect on endothelial senescence in hyperlipidemic rats through a mechanism involving down-regulation of miR-21-5p/203a-3p, which leads to the restoration of Drp1 level and recovery of mitochondrial function. Our findings highlight a novel non-lipid effect for atorvastatin besides its function in modulation of lipids.

Combination of Emricasan with Ponatinib Synergistically Reduces Ischemia/Reperfusion Injury in Rat Brain Through Simultaneous Prevention of Apoptosis and Necroptosis.

Apoptosis and receptor-interacting protein kinase 1/3(RIPK1/3)-mediated necroptosis contribute to the cerebral ischemia/reperfusion (I/R) injury. Emricasan is an inhibitor of caspases in clinical trials for liver diseases while ponatinib could be a potential inhibitor for RIPK1/3. This study aims to investigate the effect of emricasan and/or ponatinib on cerebral I/R injury and the underlying mechanisms. Firstly, we evaluated the status of apoptosis and necroposis in a rat model of cerebral I/R under different conditions, which showed noticeable apoptosis and necroptosis under condition of 2-h ischemia and 24-h reperfusion; next, the preventive or therapeutic effect of emricasan or ponatinib on cerebral I/R injury was tested. Administration of emricasan or ponatinib either before or after ischemia could decrease the neurological deficit score and infarct volume; finally, the combined therapeutic effect of emricasan with ponatinib on I/R injury was examined. Combined application of emricasan and ponatinib could further decrease the I/R injury compared to single application. Emricasan decreased the activities of capase-8/-3 in the I/R-treated brain but not the protein levels of necroptosis-relevant proteins: RIPK1, RIPK3, and mixed lineage kinase domain-like (MLKL), whereas ponatinib suppressed the expressions of these proteins but not the activities of capase-8/-3. Combination of emricasan with ponatinib could suppress both capase-8/-3 and necroptosis-relevant proteins. Based on these observations, we conclude that combination of emricasan with ponatinib could synergistically reduce I/R injury in rat brain through simultaneous prevention of apoptosis and necroptosis. Our findings might lay a basis on extension of the clinical indications for emricasan and ponatinib in treating ischemic stroke.

Lipoic acid protects gastric mucosa from ethanol-induced injury in rat through a mechanism involving aldehyde dehydrogenase 2 activation.

Numerous studies demonstrate that reactive aldehydes are highly toxic and aldehyde dehydrogenase 2 (ALDH2)-mediated detoxification of reactive aldehydes is thought as an endogenous protective mechanism against reactive aldehydes-induced cell injury. This study aims to explore whether lipoic acid, a potential ALDH2 activator, is able to protect gastric mucosa from ethanol-induced injury through a mechanism involving clearance of reactive aldehydes. The rats received 60% of acidified ethanol through intragastric administration and held for 1 h to establish a mucosal injury model. Lipoic acid (10 or 30 mg/kg) or Alda-1 (a positive control, 10 mg/kg) was given 45 min before the ethanol treatment. The gastric tissues were collected for analysis of gastric ulcer index, cellular apoptosis, 4-hydroxy-2-nonenal (4-HNE) and malondialdehyde (MDA) contents, and ALDH2 activity. The results showed that acute administration of ethanol led to an increase in gastric ulcer index, cellular apoptosis, 4-HNE and MDA contents concomitant with a decrease in ALDH2 activity; these phenomena were reversed by lipoic acid or Alda-1. The gastric protection of lipoic acid was attenuated in the presence of ALDH2 inhibitor. Based on these observations, we conclude that lipoic acid exerts the beneficial effects on ethanol-induced injury through a mechanism involving, at least in part, ALDH2 activation. As a dietary supplement or a medicine already in some countries, lipoic acid can be used to treat the ethanol - induced gastric mucosal injury.

Role of Asymmetrical Dimethylarginine in Diabetic Microvascular Complications.

Microvascular complications are the leading causes of acquired blindness, end-stage renal failure, and varieties of neuropathy associated with diabetes. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, is involved in endothelial dysfunction, oxidative stress, and inflammation associated with the progression of diabetic microvascular complications. Elevated ADMA has been detected in experimental animals and patients with diabetic microangiopathy like retinopathy, nephropathy, and neuropathy. In the review, we focus on the role of ADMA in the pathobiology of major microvascular complications of diabetes.