Dioscin alleviates lung ischemia/reperfusion injury by regulating FXR-mediated oxidative stress, apoptosis, and inflammation

Fatty acids metabolism in ozone-induced pulmonary inflammatory injury: Evidence, mechanism and prevention

Ozone (O3) is a major air pollutant that directly threatens the respiratory system, lung fatty acid metabolism disorder is an important molecular event in pulmonary inflammatory diseases. Liver kinase B1 (LKB1) and nucleotide-binding domain leucine-rich repeat-containing protein 3 (NLRP3) inflammasome not only regulate inflammation, but also have close relationship with fatty acid metabolism. However, the role and mechanism of LKB1 and NLRP3 inflammasome in lung fatty acid metabolism, which may contribute to ozone-induced lung inflammation, remain unclear, and effective strategy for preventing O3-induced pulmonary inflammatory injury is lacking. To explore these, mice were exposed to 1.00 ppm O3 (3 h/d, 5 days), and pulmonary inflammation was determined by airway hyperresponsiveness, histopathological examination, total cells and cytokines in bronchoalveolar lavage fluid (BALF). Targeted fatty acids metabolomics was used to detect medium and long fatty acid in lung tissue. Then, using LKB1-overexpressing adenovirus and NLRP3 knockout (NLRP3-/-) mice to explore the mechanism of O3-induced lung fatty acid metabolism disorder. Results demonstrated that O3 exposure caused pulmonary inflammatory injury and lung medium and long chain fatty acids metabolism disorder, especially decreased dihomo-γ-linolenic acid (DGLA). Meanwhile, LKB1 expression was decreased, and NLRP3 inflammasome was activated in lung of mice after O3 exposure. Additionally, LKB1 overexpression alleviated O3-induced lung inflammation and inhibited the activation of NLRP3 inflammasome. And we found that pulmonary fatty acid metabolism disorder was ameliorated of NLRP3 -/- mice compared with those in wide type mice after O3 exposure. Furthermore, administrating DGLA intratracheally prior to O3 exposure significantly attenuated O3-induced pulmonary inflammatory injury. Taken together, these findings suggest that fatty acids metabolism disorder is involved in O3-induced pulmonary inflammation, which is regulated by LKB1-mediated NLRP3 pathway, DGLA supplement could be a useful preventive strategy to ameliorate ozone-associated lung inflammatory injury.

Nano-enabled delivery of diosgenin and emodin ameliorates respirable silica dust-induced pulmonary fibrosis silicosis in rats

Oxidative stress and inflammation play a fundamental role in the beginning and advancement of silicosis. Hence, questing active phytocompounds (APCs) with anti-oxidative and anti-inflammatory properties such as diosgenin (DG) and emodin (ED) can be a therapeutic intervention targeting silica-induced pulmonary inflammation and fibrosis. Hydrophobicity and low bioavailability are the barriers that restrict the therapeutic efficacy of DG and ED against pulmonary defects. Encapsulating these APCs in polymeric nanoparticles can overcome this limitation. The present study has thus explored the anti-inflammatory and anti-fibrotic effects of polylactic-co-glycolic acid (PLGA) nanoparticles (NPs) individually loaded with DG (DGn) or ED (EDn) and in combine DG+ED [(DG+ED)n] in respirable silica dust (RSD)-induced pulmonary fibrosis silicosis rat model. Our study found that individual and combined NPs revealed physiochemical characteristics appropriate for IV administration with sustained-drug release purposes. Physiological evaluations of RSD-induced silicosis rats suggested that no treatment could improve the body weight. Still, they reduced the lung coefficient by maintaining lung moisture. Only (DG+ED)n significantly cleared free lung silica. All interventions were found to attribute the increased per cent cell viability in BALF, reduce cytotoxicity via minimizing LDH levels, and balance the oxidant-antioxidant status in silicotic rats. The expression of inflammatory cytokines (TNF-α, IL-1β, IL-6, MCP-1, and TGF-β1) were efficiently down-regulated with NPs interventions compared to pure (DG+ED) treatment. All drug treatments significantly declined, the 8-HdG and HYP productions indicate that RSD-induced oxidative DNA damage and collagen deposition were successfully repaired. Moreover, histopathological investigations proposed that individual or combined drugs NPs interventions could decrease the fibrosis and alveolitis grades in RSD-induced silicosis rats. However, (DG+ED)n intervention significantly inhibited pulmonary fibrosis and alveolitis compared to pure (DG+ED) treatment. In conclusion, the RSD can induce oxidative stress and inflammation in rats, producing reactive oxygen species (ROS)-mediated cytotoxicity to pulmonary cells and leading to silicosis development. The IV administration of combined NP suppressed lung inflammation and collagen formation by maintaining oxidant-antioxidant status and effectively interrupting the fibrosis-silicosis progression. These results may be attributed to the improved bioavailability of DG and ED through their combined nano-encapsulation-mediated targeted drug delivery.

Penehyclidine hydrochloride alleviates lung ischemia-reperfusion injury by inhibiting pyroptosis

OBJECTIVE

The aim of this research was to examine how penehyclidine hydrochloride (PHC) impacts the occurrence of pyroptosis in lung tissue cells within a rat model of lung ischemia-reperfusion injury.

METHODS

Twenty-four Sprague Dawley (SD) rats, weighing 250 g to 270 g, were randomly distributed into three distinct groups as outlined below: a sham operation group (S group), a control group (C group), and a test group (PHC group). Rats in the PHC group received a preliminary intravenous injection of PHC at a dose of 3 mg/kg. At the conclusion of the experiment, lung tissue and blood samples were collected and properly stored for subsequent analysis. The levels of malondialdehyde, superoxide dismutase, and myeloperoxidase in the lung tissue, as well as IL-18 and IL-1β in the blood serum, were assessed using an Elisa kit. Pyroptosis-related proteins, including Caspase1 p20, GSDMD-N, and NLRP3, were detected through the western blot method. Additionally, the dry-to-wet ratio (D/W) of the lung tissue and the findings from the blood gas analysis were also documented.

RESULTS

In contrast to the control group, the PHC group showed enhancements in oxygenation metrics, reductions in oxidative stress and inflammatory reactions, and a decrease in lung injury. Additionally, the PHC group exhibited lowered levels of pyroptosis-associated proteins, including the N-terminal segment of gasdermin D (GSDMD-N), caspase-1p20, and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3).

CONCLUSION

Pre-administration of PHC has the potential to mitigate lung ischemia-reperfusion injuries by suppressing the pyroptosis of lung tissue cells, diminishing inflammatory reactions, and enhancing lung function. The primary mechanism behind anti-pyroptotic effect of PHC appears to involve the inhibition of oxidative stress.

Suppression of Lung Oxidative Stress, Inflammation, and Fibrosis following Nitrogen Mustard Exposure by the Selective Farnesoid X Receptor Agonist Obeticholic Acid

Nitrogen mustard (NM) is a cytotoxic vesicant known to cause pulmonary injury that can progress to fibrosis. NM toxicity is associated with an influx of inflammatory macrophages in the lung. Farnesoid X receptor (FXR) is a nuclear receptor involved in bile acid and lipid homeostasis that has anti-inflammatory activity. In these studies, we analyzed the effects of FXR activation on lung injury, oxidative stress, and fibrosis induced by NM. Male Wistar rats were exposed to phosphate-buffered saline (vehicle control) or NM (0.125 mg/kg) by intratracheal Penncentury-MicroSprayer aerosolization; this was followed by treatment with the FXR synthetic agonist, obeticholic acid (OCA, 15 mg/kg), or vehicle control (0.13-0.18 g peanut butter) 2 hours later and then once per day, 5 days per week thereafter for 28 days. NM caused histopathological changes in the lung, including epithelial thickening, alveolar circularization, and pulmonary edema. Picrosirius red staining and lung hydroxyproline content were increased, indicative of fibrosis; foamy lipid-laden macrophages were also identified in the lung. This was associated with aberrations in pulmonary function, including increases in resistance and hysteresis. Following NM exposure, lung expression of HO-1 and iNOS, and the ratio of nitrates/nitrites in bronchoalveolar lavage fluid (BAL), markers of oxidative stress increased, along with BAL levels of inflammatory proteins, fibrinogen, and sRAGE. Administration of OCA attenuated NM-induced histopathology, oxidative stress, inflammation, and altered lung function. These findings demonstrate that FXR plays a role in limiting NM-induced lung injury and chronic disease, suggesting that activating FXR may represent an effective approach to limiting NM-induced toxicity. SIGNIFICANCE STATEMENT: In this study, the role of farnesoid-X-receptor (FXR) in mustard vesicant-induced pulmonary toxicity was analyzed using nitrogen mustard (NM) as a model. This study's findings that administration of obeticholic acid, an FXR agonist, to rats reduces NM-induced pulmonary injury, oxidative stress, and fibrosis provide novel mechanistic insights into vesicant toxicity, which may be useful in the development of efficacious therapeutics.

Repetitive Low-Level Blast Exposure via Akt/NF-κB Signaling Pathway Mediates the M1 Polarization of Mouse Alveolar Macrophage MH-S Cells

Repetitive low-level blast (rLLB) exposure is a potential risk factor for the health of soldiers or workers who are exposed to it as an occupational characteristic. Alveolar macrophages (AMs) are susceptible to external blast waves and produce pro-inflammatory or anti-inflammatory effects. However, the effect of rLLB exposure on AMs is still unclear. Here, we generated rLLB waves through a miniature manual Reddy-tube and explored their effects on MH-S cell morphology, phenotype transformation, oxidative stress status, and apoptosis by immunofluorescence, real-time quantitative PCR (qPCR), western blotting (WB) and flow cytometry. Ipatasertib (GDC-0068) or PDTC was used to verify the role of the Akt/NF-κB signaling pathway in these processes. Results showed that rLLB treatment could cause morphological irregularities and cytoskeletal disorders in MH-S cells and promote their polarization to the M1 phenotype by increasing iNOS, CD86 and IL-6 expression. The molecular mechanism is through the Akt/NF-κB signaling pathway. Moreover, we found reactive oxygen species (ROS) burst, Ca²⁺ accumulation, mitochondrial membrane potential reduction, and early apoptosis of MH-S cells. Taken together, our findings suggest rLLB exposure may cause M1 polarization and early apoptosis of AMs. Fortunately, it is blocked by specific inhibitors GDC-0068 or PDTC. This study provides a new treatment strategy for preventing and alleviating health damage in the occupational population caused by rLLB exposure.

Ferroptosis-modulating small molecules for targeting drug-resistant cancer: Challenges and opportunities in manipulating redox signaling

Ferroptosis is an iron-dependent cell death program that is characterized by excessive lipid peroxidation. Triggering ferroptosis has been proposed as a promising strategy to fight cancer and overcome drug resistance in antitumor therapy. Understanding the molecular interactions and structural features of ferroptosis-inducing compounds might therefore open the door to efficient pharmacological strategies against aggressive, metastatic, and therapy-resistant cancer. We here summarize the molecular mechanisms and structural requirements of ferroptosis-inducing small molecules that target central players in ferroptosis. Focus is placed on (i) glutathione peroxidase (GPX) 4, the only GPX isoenzyme that detoxifies complex membrane-bound lipid hydroperoxides, (ii) the cystine/glutamate antiporter system Xc - that is central for glutathione regeneration, (iii) the redox-protective transcription factor nuclear factor erythroid 2-related factor (NRF2), and (iv) GPX4 repression in combination with induced heme degradation via heme oxygenase-1. We deduce common features for efficient ferroptotic activity and highlight challenges in drug development. Moreover, we critically discuss the potential of natural products as ferroptosis-inducing lead structures and provide a comprehensive overview of structurally diverse biogenic and bioinspired small molecules that trigger ferroptosis via iron oxidation, inhibition of the thioredoxin/thioredoxin reductase system or less defined modes of action.

Anticancer Activity of Methyl Protodioscin against Prostate Cancer by Modulation of Cholesterol-Associated MAPK Signaling Pathway <i>via</i> FOXO1 Induction

Methyl protodioscin (MPD), a furostanol saponin found in the rhizomes of Dioscoreaceae, has lipid-lowering and broad anticancer properties. However, the efficacy of MPD in treating prostate cancer remains unexplored. Therefore, the present study aimed to evaluate the anticancer activity and action mechanism of MPD in prostate cancer. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound healing, transwell, and flow cytometer assays revealed that MPD suppressed proliferation, migration, cell cycle, and invasion and induced apoptosis of DU145 cells. Mechanistically, MPD decreased cholesterol concentration in the cholesterol oxidase, peroxidase and 4-aminoantipyrine phenol (COD-PAP) assay, disrupting the lipid rafts as detected using immunofluorescence and immunoblot analyses after sucrose density gradient centrifugation. Further, it reduced the associated mitogen-activated protein kinase (MAPK) signaling pathway protein P-extracellular regulated protein kinase (ERK), detected using immunoblot analysis. Forkhead box O (FOXO)1, a tumor suppressor and critical factor controlling cholesterol metabolism, was predicted to be a direct target of MPD and induced by MPD. Notably, in vivo studies demonstrated that MPD significantly reduced tumor size, suppressed cholesterol concentration and the MAPK signaling pathway, and induced FOXO1 expression and apoptosis in tumor tissue in a subcutaneous mouse model. These results suggest that MPD displays anti-prostate cancer activity by inducing FOXO1 protein, reducing cholesterol concentration, and disrupting lipid rafts. Consequently, the reduced MAPK signaling pathway suppresses proliferation, migration, invasion, and cell cycle and induces apoptosis of prostate cancer cells.

Neuroprotective effect of a Keap1-Nrf2 Protein-Protein Inter-action inhibitor on cerebral Ischemia/Reperfusion injury

Oxidative stress has been confirmed to be closely related to the occurrence and development of cerebral ischemic/reperfusion (I/R). The Keap1-Nrf2 pathway is widely recognized as a defensive system to maintain cellular redox homeostasis. Targeting Keap1-Nrf2 interaction by small molecules to release Nrf2 should be a promising strategy to treat cerebral I/R injury. The piperazinyl-naphthalenesulfonamide 6 K was reported to be a Keap1-Nrf2 protein-protein interaction inhibitor, showing promising antioxidative effect. Herein, this study is to investigate whether 6 K could prevent brain from I/R injury. The related mechanism of oxidative stress was also elucidated using in vivo mice middle cerebral artery occlusion (MCAO) model and in vitro SH-SY5Y oxygen-glucose deprivation/reperfusion (OGD/R) model. The results indicated that treatment of 6 K markedly decreased infarct volume, apoptotic neurons and oxidative damage and promoted neurologic recovery in vivo. The cell model revealed that the reactive oxygen species (ROS) was decreased, and cell viability was increased. Western blots and immunofluorescence staining demonstrated that compound treatment promoted Nrf2 release and nuclear translocation. The downstream protective enzymes were significantly enhanced at both in vivo and in vitro levels. Collectively, 6 K is a promising protective agent against cerebral I/R injury through activation of Nrf2 to suppress oxidative stress.

Baicalin inhibits oxidative injures of mouse uterine tissue induced by acute heat stress through activating the Keap1/Nrf2 signaling pathway

Heat stress effect the physiological functions of body, and reproductive system is one of the most sensitive. It's imperative to find out suitable measures to alleviate harmful effects of heat stress. Baicalin is well-known with its antioxidative property. To examine whether Baicalin could reduce oxidative injures of uterine tissue in heat-stressed mice. The mice were divided into four groups: control (Con), Baicalin (Bai), heat stress (H) and heat stress plus Baicalin (H + Bai). The oxidative damage of uterine tissue was detected by ELISA, H&E staining, tunnel assay and immunohistochemical staining. The protein/mRNA expressions of Keap1/Nrf2 related factors were detected by Western blot or QPCR. The results showed that mice heat-stressed at 41 °C for 2 h induced macroscopic changes, significantly increased MDA content and reduced activities of antioxidant enzymes including SOD, CAT and GSH-Px of the uterine tissue. Compared with Con group, heat stress up-regulated caspase-3 and caspase-9, enhanced the apoptosis of endometrial epithelial and glandular epithelial cells, improved the HO-1 mRNA/protein and NQO1 protein expressions, while down-regulated the mRNA/protein of Keap1. Compared with H group, antioxidant enzyme activities, Nrf2 protein and Nrf2, NQO1 and GCLC mRNA expressions were significantly increased in the H + Bai group. While the uterine epithelial cells apoptosis, MDA contents, caspase-3, caspase-9 and Keap1 protein and HO-1 mRNA expressions were decreased in the H + Bai group of mice compared with that in H group. Briefly, acute heat stress causes oxidative injures and apoptosis of mouse uterine tissue and Baicalin protects uterine tissue from the damages possibly through Keap1/Nrf2 signaling pathway.

ALDA-1 TREATMENT ALLEVIATES LUNG INJURY AFTER CARDIAC ARREST AND RESUSCITATION IN SWINE

ABSTRACT

Introduction: Alda-1, an aldehyde dehydrogenase 2 (ALDH2) activator, has been shown to protect the lung against a variety of diseases including regional ischemia-reperfusion injury, severe hemorrhagic shock, hyperoxia, and so on. The present study was designed to investigate the effectiveness of Alda-1 treatment in alleviating lung injury after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) in swine. Methods: A total of 24 swine were randomized into three groups: sham (n = 6), CA/CPR (n = 10), and CA/CPR + Alda-1 (n = 8). The swine model was established by 8 min of electrically induced and untreated CA, and then 8 min of manual CPR. A dose of 0.88 mg/kg of Alda-1 was intravenously injected at 5 min after CA/CPR. After CA/CPR, extravascular lung water index (ELWI), pulmonary vascular permeability index (PVPI), and oxygenation index (OI) were regularly evaluated for 4 h. At 24 h after resuscitation, lung ALDH2 activity was detected, and its injury score, apoptosis, and ferroptosis were measured. Results: After experiencing the same procedure of CA and CPR, five swine in the CA/CPR group and six swine in the CA/CPR + Alda-1 group restored spontaneous circulation. Subsequently, significantly increased ELWI and PVPI, and markedly decreased OI were observed in these two groups compared with the sham group. However, all of them were gradually improved and significantly better in the swine treated with the Alda-1 compared with the CA/CPR group. Tissue analysis indicated that lung ALDH2 activity was significantly decreased in those swine experiencing the CA/CPR procedure compared with the sham group; nevertheless, its activity was significantly greater in the CA/CPR + Alda-1 group than in the CA/CPR group. In addition, lung injury score, and its apoptosis and ferroptosis were significantly increased in the CA/CPR and CA/CPR + Alda-1 groups compared with the sham group. Likewise, Alda-1 treatment significantly decreased these pathological damages in lung tissue when compared with the CA/CPR group. Conclusions: Alda-1 treatment was effective to alleviate lung injury after CA/CPR in a swine model, in which the protective role was possibly related to the inhibition of cell apoptosis and ferroptosis. It might provide a novel therapeutic target and a feasible therapeutic drug for lung protection after CA/CPR.

Farnesoid-X receptor as a therapeutic target for inflammatory bowel disease and colorectal cancer

Farnesoid-X receptor (FXR), as a nuclear receptor activated by bile acids, is a vital molecule involved in bile acid metabolism. Due to its expression in immune cells, FXR has a significant effect on the function of immune cells and the release of chemokines when immune cells sense changes in bile acids. In addition to its regulation by ligands, FXR is also controlled by post-translational modification (PTM) activities such as acetylation, SUMOylation, and methylation. Due to the high expression of FXR in the liver and intestine, it significantly influences intestinal homeostasis under the action of enterohepatic circulation. Thus, FXR protects the intestinal barrier, resists bacterial infection, reduces oxidative stress, inhibits inflammatory reactions, and also acts as a tumor suppressor to impair the multiplication and invasion of tumor cells. These potentials provide new perspectives on the treatment of intestinal conditions, including inflammatory bowel disease (IBD) and its associated colorectal cancer (CRC). Moreover, FXR agonists on the market have certain organizational heterogeneity and may be used in combination with other drugs to achieve a greater therapeutic effect. This review summarizes current data on the role of FXR in bile acid metabolism, regulation of immune cells, and effects of the PTM of FXR. The functions of FXR in intestinal homeostasis and potential application in the treatment of IBD and CRC are discussed.

Dioscin alleviates myocardial infarction injury via regulating BMP4/NOX1-mediated oxidative stress and inflammation

BACKGROUND

Dioscin, a steroidal saponin natural product, has various pharmacological activities, such as anti-inflammatory, antioxidant, lipid-lowering. However, little is known about its effects on myocardial infarction (MI) injury. Thus, the study aimed to investigate the protective effects and possible mechanisms of dioscin.

METHODS

We evaluated protective effects of Dioscin on HL-1 cells after hypoxia based on MTT and ROS in vitro. In vivo, we ligated left anterior descending (LAD) of C57BL/6 mice to establish MI model and assess serum levels of LDH, CK-MB, cTnI, SOD, MDA and CAT treated by dioscin. In addition, myocardial damages were reflected by H&E, masson and ultrastructural examination and Electrocardiograph (ECG) was detected in MI mice. And the BMP4/NOX1 pathway was measured by western blotting, immunofluorescence assay and Real-time PCR. Furthermore, to investigate cardio-protective effects of dioscin via targeting BMP4, we transfected siBMP4 into HL-1 cells in vitro and injected BMP4 siRNA though tail veins in vivo.

RESULTS

In vitro, dioscin significantly increased the viability of HL-1 cells and inhibited ROS level under hypoxia. In vivo, dioscin markedly reduced the elevation of ST segment and alleviated myocardial infarct area in mice. In terms of serology, dioscin evidently decreased LDH, CK-MB, cTnI, MDA levels, and increased SOD level. In addition, dioscin improved the pathological status of myocardial tissue and restrained the production of collagen fibers. Mechanism study proved that dioscin notablely regulated the levels of Nrf2, Keap1, HO-1, p-NF-κB, nNF-κB, TNF-α, IL-1β and IL-6 by down-regulating the protein levels of BMP4 and NOX1 against oxidative stress and inflammation. Further investigation showed that siBMP4 transfection diminished hypoxia and MI-induced oxidative and inflammation injury. The transfection decreased LDH, CK-MB and cTnI levels, improved ischemia T-wave inversion and reduced striated muscle necrosis, nucleus dissolution, collagen fibrosis and mitochondrial swelling in mice. In addition, siBMP4 decreased ROS and MDA levels, increased SOD and CAT levels and down-regulated mRNA levels of TNF-α, IL-1β and IL-6. Moreover, BMP4, NOX1 and nNF-κB protein levels were decreased and Nrf2 levels were increased by siBMP4.

CONCLUSION

Our study confirmed that dioscin showed an outstanding anti-myocardial infarction effect via regulating BMP4/NOX1-mediated oxidative stress and inflammation, which has a promising application value and development prospect against MI injury in the future.

Oyster (Crassostrea gigas) Polysaccharide Ameliorates High-Fat-Diet-Induced Oxidative Stress and Inflammation in the Liver via the Bile Acid-FXR-AMPKα Pathway

Oyster polysaccharides (OPS) have a variety of biological activities. In this study, we aimed to investigate the potential mechanisms of OPS to ameliorate hepatic oxidative stress and inflammation in mice induced by a high-fat diet (HFD). The results showed that OPS reduced the HFD-induced increases in serum transaminase levels and alleviated hepatic oxidative stress and inflammation. Moreover, OPS regulated bile acid metabolism and increased bile acid content in the liver, serum, and feces. Serum bile acid profile results indicated that OPS reduced levels of chenodeoxycholic acid, deoxycholic acid, and lithocholic acid associated with high-affinity agonists of Farnesol X receptor (FXR). Western blot analysis showed that OPS accelerated bile acid metabolism by downregulating hepatic FXR expression and promoting its downstream CYP7A1, CYP27A1, and CYP8B1 protein expression. Meanwhile, OPS ameliorated oxidative stress and inflammation in the liver by modulating FXR-AMPKα-Nrf2/NF-κB signaling to reduce p-IκBα/IκBα, p-NF-κB p65/NF-κB p65, IL-1β, and TNF-α expression and increase p-Nrf2/Nrf2, HO-1, and NQO-1 expression. This study was the first to explore the possible mechanism of OPS in improving liver oxidative stress and inflammation from the perspective of bile acid metabolism, providing a theoretical basis for OPS as a new source of functional food.

Dioscin Alleviates Cardiac Dysfunction in Acute Myocardial Infarction via Rescuing Mitochondrial Malfunction

Myocardial infarction is one of the most severe heart diseases, leading to sudden death. Currently, angiography and stenting are widely performed in clinics, yet more effective treatment is still needed. Herein, we presented that dioscin, a natural product, showed protective effect on infarcted hearts via mitochondrial maintenance. Upon dioscin treatment, cardiac dysfunction was alleviated, and remodeling is prevented. Mechanistically, disocin maintains mitochondria function through the maintenance of Kreb's cycle, and suppresion of ROS accumulation. In this way, by targeting mitochondrial dysfunction, dioscin is a potential drug for infarcted hearts.

Metformin attenuates high glucose-induced injury in islet microvascular endothelial cells

As one of the most frequently prescribed antidiabetic drugs, metformin can lower glucose levels, improve insulin resistance manage body weight. However, the effect of metformin on islet microcirculation remains unclear. In the present study, to explore the effect of metformin on islet endothelial cells and investigated the underlying mechanism, we assessed the effects of metformin on islet endothelial cell survival, proliferation, oxidative stress and apoptosis. Our results suggest that metformin stimulates the proliferation of pancreatic islet endothelial cells and inhibits the apoptosis and oxidative stress caused by high glucose levels. By activating farnesoid X receptor (FXR), metformin increases the expression of vascular endothelial growth factor-A (VEGF-A) and endothelial nitric oxide synthase (eNOS), improves the production of nitric oxide (NO) and decreases the production of ROS. After the inhibition of FXR or VEGF-A, all of the effects disappeared. Thus, metformin appears to regulate islet microvascular endothelial cell (IMEC) proliferation, apoptosis and oxidative stress by activating the FXR/VEGF-A/eNOS pathway. These findings provide a new mechanism underlying the islet-protective effect of metformin.