Search

Purpose Tinnitus is a phantom perception of sound in the absence of acoustic source. Previous evidence has indicated that miR-375-3p is downregulated in rats with tinnitus in comparison to the controls. Nevertheless, its molecular mechanism underlying tinnitus pathogenesis is unclarified. Methods SH-SY5Y cells were differentiated into neuronlike cells and stimulated with salicylate to mimic tinnitus in vitro. Immunofluorescence staining was utilized for measuring expression of NR2B (glutamate ionotropic receptor NMDA type subunit 2B). Intracellular reactive oxygen species (ROS) level was determined using DCFH-DA assay kit. Real-time quantitative polymerase chain reaction as well as western blotting was utilized for examining RNA and protein levels. Luciferase reporter assay was implemented for verifying the interaction between miR-375-3p and ELAVL4 (ELAV-like RNA-binding protein 4). Results Salicylate treatment enhanced levels of NR2B and the early immediate gene ARC as well as ROS production. miR-375-3p was downregulated in salicylate-treated group. Overexpressing miR-375-3p attenuated the effects induced by salicylate in SH-SY5Y cells. miR-375-3p targeted ELAVL4 and upregulating ELAVL4 reversed miR-375-3p upregulation–triggered effects on SH-SY5Y cells under salicylate treatment. Conclusion miR-375-3p mitigates salicylate-triggered neuronal injury in SH-SY5Y cells by regulating ELAVL4 expression.

Icariside II (ICAII) is a bioflavonoid compound which has demonstrated anti‑oxidative, anti‑inflammatory and anti‑apoptotic biological activities. However, to the best of our knowledge, whether ICAII can alleviate myocardial ischemia and reperfusion injury (MIRI) remains unknown. The aim of the present study was to determine whether ICAII exerted a protective effect on MIRI and to investigate the potential underlying mechanism of action. A rat MIRI model was established by ligation of the left anterior descending coronary artery for 30 min, followed by a 24 h reperfusion. Pretreatment with ICAII with or without a PI3K/AKT inhibitor was administered at the beginning of reperfusion. Morphological and histological analyses were detected using hematoxylin and eosin staining; the infarct size was measured using Evans blue and 2,3,5‑triphenyltetrazolium chloride staining; and plasma levels of lactate dehydrogenase (LDH) and creatine kinase‑myocardial band (CK‑MB) were analyzed using commercialized assay kits. In addition, the cardiac function was evaluated by echocardiography and the levels of cardiomyocyte apoptosis were determined using a TUNEL staining. The protein expression levels of Bax, Bcl‑2, cleaved caspase‑3, interleukin‑6, tumor necrosis factor‑α, PI3K, phosphorylated (p)‑PI3K, AKT and p‑AKT were analyzed using western blotting analysis. ICAII significantly reduced the infarct size, decreased the release of LDH and CK‑MB and improved the cardiac function induced by IR injury. Moreover, ICAII pretreatment significantly inhibited myocardial apoptosis and the inflammatory response. ICAII also upregulated the expression levels of p‑PI3K and p‑AKT. However, the protective effects of ICAII were abolished by an inhibitor (LY294002) of the PI3K/AKT signaling pathway. In conclusion, the findings of the present study suggested that ICAII may mitigate MIRI by activating the PI3K/AKT signaling pathway.

The 1‐year mortality and health consequences of COVID‐19 in cancer patients are relatively underexplored. In this multicenter cohort study, 166 COVID‐19 patients with cancer were compared with 498 non‐cancer COVID‐19 patients and 498 non‐COVID cancer patients. The 1‐year all‐cause mortality and hospital mortality rates in Cancer COVID‐19 Cohort (30% and 20%) were significantly higher than those in COVID‐19 Cohort (9% and 8%, both P

Purpose: Computed tomography (CT) characteristics associated with critical outcomes of patients with coronavirus disease 2019 (COVID-19) have been reported. However, CT risk factors for mortality have not been directly reported. We aim to determine the CT-based quantitative predictors for COVID-19 mortality.Methods: In this retrospective study, laboratory-confirmed COVID-19 patients at Wuhan Central Hospital between December 9, 2019, and March 19, 2020, were included. A novel prognostic biomarker, V-HU score, depicting the volume (V) of total pneumonia infection and the average Hounsfield unit (HU) of consolidation areas was automatically quantified from CT by an artificial intelligence (AI) system. Cox proportional hazards models were used to investigate risk factors for mortality.Results: The study included 238 patients (women 136/238, 57%; median age, 65 years, IQR 51–74 years), 126 of whom were survivors. The V-HU score was an independent predictor (hazard ratio [HR] 2.78, 95% confidence interval [CI] 1.50–5.17; p = 0.001) after adjusting for several COVID-19 prognostic indicators significant in univariable analysis. The prognostic performance of the model containing clinical and outpatient laboratory factors was improved by integrating the V-HU score (c-index: 0.695 vs. 0.728; p < 0.001). Older patients (age ≥ 65 years; HR 3.56, 95% CI 1.64–7.71; p < 0.001) and younger patients (age < 65 years; HR 4.60, 95% CI 1.92–10.99; p < 0.001) could be further risk-stratified by the V-HU score.Conclusions: A combination of an increased volume of total pneumonia infection and high HU value of consolidation areas showed a strong correlation to COVID-19 mortality, as determined by AI quantified CT.

The aim of the current study was to investigate the effect and mechanism of schisandrin B (Sch B) on myocardial hypertrophy induced by pressure overload in mice. Male C57BL/6J mice were randomly divided into three groups: i) Sham (n=12); ii) transverse aortic constriction (TAC) (n=12); and iii) Sch B-treated (n=12; 80 mg·kg-1·d-1 per gavage). The model of myocardial hypertrophy was established by constricting the descending branch of the aortic arch. Following a 4-week treatment period, cardiac remodeling was evaluated using echocardiography and pathological and molecular analysis. Sch B improved cardiac function in the Sch B-treated group compared with the TAC group. Moreover, the Sch B-treated group had a smaller myocardial cell cross-sectional area and less fibrosis compared with the TAC group. The protein expression levels of cardiac hypertrophy and fibrosis markers in the TAC group were significantly higher compared with those in the sham group. The same markers in the Sch B-treated group were significantly lower compared with those in the TAC group. Additionally, the phosphorylation levels of the mitogen-activated protein kinase (MAPK) signaling pathway-associated proteins extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase 1/2 and P38 mitogen-activated protein kinase were significantly lower in the Sch B-treated group compared with the TAC group. Further in vitro investigation demonstrated that Sch B prevented the adverse effects of angiotensin II-induced hypertrophy and fibrosis by inhibiting the MAPK signaling pathway in H9c2 cells. In conclusion, Sch B may improve pathological myocardial remodeling and cardiac function induced by pressure overload, and its underlying mechanism may be associated with inhibition of the MAPK signaling pathway.

Inflammation parameters were verified to predict clinical outcomes of metastatic renal cell carcinoma (mRCC) patients treated with tyrosine kinase inhibitors (TKIs). Here, we developed a novel marker, lactate dehydrogenase (tumor burden marker) to lymphocytes (inflammation marker) ratio (LLR), aimed to reveal the prognostic role of LLR for mRCC patients treated with TKIs. We collected clinical data of mRCC patients treated with TKIs. Receiver operating curve analysis was used to determine the optimal cut-off value. The c-index method was used to determine the best predictive marker for overall survival (OS). Clinicopathological characteristics on OS and progression-free survival (PFS) were evaluated by univariate analysis, and multivariate analyses. LLR provided the greatest improvement in the c-index, and displayed the best marker of the prognostic accuracy for OS. Univariate analysis revealed that LLR, ECOG PS and IMDC risks were significant predictors of OS and PFS. However, multivariate analysis indicated that IMDC risks failed to predict PFS, and only showed predictor of OS. We finally stratifed patients into low LLR (

Epidermal growth factor receptor (EGFR) is a therapeutic target in nasopharyngeal carcinoma (NPC). The optimal combined modality of optimal combined modality of anti-­EGFR monoclonal antibodies, induction chemotherapy (ICT), concurrent chemotherapy and radiotherapy for NPC remains poorly defined. None of previous studies have developed subsequent treatment strategies on the basis of stratification according to the efficacy following ICT plus anti-EGFR mAbs. This study aims to increase treatment intensity for patients with poor efficacy of ICT and reduce treatment toxicity for patients with favourable efficacy of ICT by assessing whether the efficacy of this treatment regimen is non-inferior to ICT plus concurrent chemoradiotherapy (historic controls).IntroductionMethods and analysisPathology-confirmed WHO type II/III NPC patients at clinical stage III–IVA (eighth American Joint Committee on Cancer/Union for International Cancer Control staging system) will be included in the study. They will receive ICT plus nimotuzumab (NTZ), followed by radiotherapy plus NTZ or concurrent chemoradiotherapy plus NTZ (stratified based on the efficacy of ICT plus NTZ). The primary endpoint is 3-year failure-free survival rate; while the secondary endpoints are 3-year overall survival rate, distant metastasis-free survival rate and locoregional recurrence-free survival rate, and short-term remission rate of tumour and treatment toxicity.Ethics and disseminationThe study protocol has been approved by the Ethics Committee of the Second Affiliated Hospital of Nanchang University. Our findings will be disseminated in a peer-reviewed journal. Implementation strategies are in place to ensure privacy and confidentiality of participants.Trial registration numberChiCTR2000041139.

Background The study aim was to investigate one-year all-cause mortality and health consequences of cancer COVID-19 patients in China, stratified by primary tumor subtype. Methods In this multicenter cohort study, 166 cancer COVID-19 patients were studied along with 498 gender- and age-matched non-cancer COVID-19 patients in four hospitals in Wuhan, China, admitted 2020/01/01-2020/03/18, as well as with 498 parallel gender-, age-, and cancer subtype- matched non-COVID cancer patients hospitalized between 2019/01/01-2020/03/17. All patients were followed-up with a telephone survey to assess health consequences. Cox proportional hazards regression were used for risk analysis. Results In the three cohorts of median age of 65 ± 1 year and 49% male, the one-year all-cause mortality and hospital mortality rates of Cancer COVID-19 Cohort, 30% and 20% respectively, were significantly higher than COVID-19 Cohort (9% and 8%), and Cancer Cohort (16% and 2%). The 12-month all-cause post-discharge mortality rate of Cancer COVID-19 Cohort (11%) was higher than COVID-19 Cohort (0.4%), but similar to Cancer Cohort (15%). The high 1-year all-cause mortality was among hematologic malignancies (65%) and then nasopharyngeal, brain and skin tumors (45%), digestive system (43%), and lung (32%). the rate was low among genitourinary (14%), female genital (13%), breast (11%), and thyroid (0). As for patients having at least one symptom at the 1-year follow-up, Cancer COVID-19 Cohort (23%, 26/114) is similar to COVID-19 Cohort (30%, 130/432). Discussion Cancer COVID-19 patients showed a high rate of hospitalization mortality, but not after discharged, signifying the strong acute adverse effect of COVID-19 on cancer patients while little was in long-term effect. Risk stratification showed that hematologic malignancies, nasopharyngeal, brain, digestive system and lung tumors were high risk, while genitourinary, female genital, breast and thyroid were low risk which was similar to non-cancer COVID-19. Conclusions COVID-19 had little effect of 1-year mortality and sequelae for cancer survivors discharged from SARS-CoV-2 virus infection. Different tumor subtypes had different effect of COVID-19. COVID-19 patients with thyroid, breast, female genital, genitourinary tumor had low risk mortality which was similar to non-cancer patients.

Endoplasmic reticulum stress (ERS)-induced apoptosis serves a crucial role in the pathogenesis of myocardial ischemia/reperfusion injury (MIRI). Previous studies have confirmed that pleckstrin homology-like domain family A member 3 (PHLDA3) is an important mediator in ERS-associated apoptosis. The aim of the current study focused on whether PHLDA3 served protective effects on hypoxia/reoxygenation (H/R)-injured cardiomyocytes by inhibiting ERS-induced apoptosis. Furthermore, the molecular mechanisms associated with the PI3K/AKT signaling pathway were investigated. Primary neonatal rat cardiomyocytes were isolated and randomized into four groups: i) Control + adenovirus encoding scrambled short hairpin RNA (AdshRNA); ii) control + adenoviral vectors encoding PHLDA3 shRNA (AdshPHLDA3); iii) H/R+ AdshRNA and iv) H/R+AdshPHLDA3. AdshPHLDA3 was used to knock down PHLDA3. An H/R injury model was constructed by treatment with hypoxia for 4 h followed by reoxygenation for 6 h. A PI3K/AKT inhibitor, LY294002, was supplemented in mechanistic studies. Cell viability and LDH/CK releases were detected to evaluate myocardial damage. Flow cytometry assays were used to assess apoptotic response. Western blotting assays were used to detect protein expression. The results demonstrated that H/R induced myocardial damage and increased PHLDA3 expression. ERS-induced apoptosis was significantly increased following H/R injury, as indicated by increased apoptotic rates and ERS-associated protein expression, including those of CHOP, 78 kDa glucose-regulated protein and caspase-12. However, PHLDA3 inhibition following AdshPHLDA3 transfection reversed cell damage and ERS-associated apoptosis on H/R injury. Studies for molecular mechanisms concluded that the apoptosis-inhibition effects and cardioprotective roles of PHLDA3 inhibition were induced partly by the activation of the PI3K/AKT pathway, which was verified by LY294002 treatment. In conclusion, in the process of H/R injury, PHLDA3 inhibition reduced ERS-induced apoptosis and H/R injury by activating the PI3K/AKT pathway. PHLDA3 may be a therapeutic target for the treatment of MIRI.

Background The management of critically ill patients with coronavirus disease 2019 (COVID‐19), caused by a new human virus severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), is challenging. Recently, there have been several reports with inconsistent results after treatment with convalescent plasma (CP) on critically ill patients with COVID‐19, which was produced with a neutralizing antibody titer and tested in a P3 or P4 laboratory. However, due to the limitation of the conditions on mass production of plasma, most producers hardly had the capability to isolate the neutralizing antibody. Here, we report the clinical courses of three critically ill patients with COVID‐19 receiving CP treatments by total immunoglobulin G (IgG) titer collection. Methods Three patients with COVID‐19 in this study were laboratory confirmed to be positive for SARS‐CoV‐2, with radiographic and clinical features of pneumonia. CP was collected by total IgG titer of 160 (range, 200‐225 mL), and patients were transfused between 20 and 30 days after disease onset at the critical illness stage as a trial in addition to standard care. The clinical courses of these patients, including laboratory results and pulmonary functional and image studies after receiving convalescent plasma infusions, were reviewed. Results No therapeutic effect of CP was observed in any of the patients; instead, all three patients deteriorated and required extracorporeal membrane oxygenation treatment. A potential cytokine storm 4 hours after infusion of CP in Patient 2 was observed. No more patients were put on the trial of CP transfusion. Conclusions We recommend extreme caution in using CP in critically ill patients more than 2 weeks after the onset of COVID‐19 pneumonia.

Background: Our study investigated the diagnostic and prognostic role of serum antioxidant indexes in patients with acute pancreatitis (AP). Methods: This study included 708 AP patients from the Medical Information Mart for Intensive Care-III (MIMIC-III) database and 477 patients from the eICU Collaborative Research Database (eICU-CRD). X-tile software was applied to determine the best cutoff values for serum antioxidant indexes. Univariate and multivariate regression analyses were employed to select variables associated with severe AP (SAP) and in-hospital mortality. Finally, the nomograms were also externally validated in the eICU-CRD. Results: The best cutoff values for serum total bilirubin (TBIL) and albumin were 1.1 mg/dL and 2.1 g/dL in the training set, respectively. Multivariate logistical regression indicated that both TBIL (odds ratio [OR]=0.740, 95% confidence interval [CI]: 0.616-0.889, P=0.001) and albumin (OR=0.890, 95%CI: 0.819-0.967, P=0.006) were independent risk factors for SAP. Similarly, multivariate Cox analysis revealed that serum TBIL (hazard ratio [HR]=0.768, 95%CI:0.635-0.928, P=0.006) and albumin (HR=0.962, 95%CI:0.927-0.998, P=0.037) were independent risk factors for in-hospital mortality in AP patients. The diagnostic nomogram containing TBIL, albumin, Sequential Organ Failure Assessment (SOFA) score and urea nitrogen and prognostic nomogram combining TBIL, albumin, white blood count, SOFA score, and age obtained good discrimination, calibration and clinical utility in both the MIMIC-III and eICU-CRD. Conclusion: Serum TBIL and albumin were independent predictors for SAP and in-hospital mortality in AP patients. The nomograms combining serum TBIL and albumin with other significant features exerted favorable predictive performance for SAP and in-hospital mortality.

Background This present study aimed to investigate the correlation of long non‐coding RNA THRIL (lnc‐THRIL) with acute respiratory distress syndrome (ARDS) risk, disease severity, inflammation, and mortality in sepsis patients. Methods A total of 109 sepsis patients admitted to intensive care units were consecutively recruited, and their blood samples were collected. After admission, patients were supervised and screened daily to identify the occurrence of ARDS. Clinical characteristics, routine laboratory testing, and disease severity were recorded, and all enrolled patients were followed up until death in the hospital or discharge for mortality records. Lnc‐THRIL was detected by quantitative polymerase chain reaction, and inflammatory cytokine levels were measured by human enzyme‐linked immunoassay. Results A total of 32 (29.4%) sepsis patients occurred ARDS and 77 (71.6%) did not. Lnc‐THRIL was upregulated in ARDS group compared with non‐ARDS group, and it had good value in distinguishing ARDS from non‐ARDS in sepsis patients (AUC: 0.706; 95%CI: 0.602‐0.809). Besides, lnc‐THRIL, smoke, and chronic obstructive pulmonary disease independently predicted increased risk of ARDS. As for disease severity, lnc‐THRIL positively correlated with APACHE II score and SOFA score in sepsis patients. Regarding inflammation, lnc‐THRIL was positively associated with CRP, PCT, TNF‐α, and IL‐1β levels in sepsis patients. Additionally, the mortality rate was 30.2%, and lnc‐THRIL was upregulated in non‐survivors compared with survivors, presenting a good value (AUC: 0.780; 95%CI: 0.683‐0.876) in predicting mortality in sepsis patients. Conclusion Lnc‐THRIL predicts increased risk of ARDS and positively correlates with disease severity, inflammation, and mortality in sepsis patients.

Background: Cardiopulmonary resuscitation (CPR) strategies in COVID-19 patients differ from those in patients suffering from cardiogenic cardiac arrest. During CPR, both healthcare and non-healthcare workers who provide resuscitation are at risk of infection. The Working Group for Expert Consensus on Prevention and Cardiopulmonary Resuscitation for Cardiac Arrest in COVID-19 has developed this Chinese Expert Consensus to guide clinical practice of CPR in COVID-19 patients. Main recommendations: 1) A medical team should be assigned to evaluate severe and critical COVID-19 for early monitoring of cardiac-arrest warning signs. 2) Psychological counseling and treatment are highly recommended, since sympathetic and vagal abnormalities induced by psychological stress from the COVID-19 pandemic can induce cardiac arrest. 3) Healthcare workers should wear personal protective equipment (PPE). 4) Mouth-to-mouth ventilation should be avoided on patients suspected of having or diagnosed with COVID-19. 5) Hands-only chest compression and mechanical chest compression are recommended. 6) Tracheal-intubation procedures should be optimized and tracheal-intubation strategies should be implemented early. 7) CPR should be provided for 20-30 min. 8) Various factors should be taken into consideration such as the interests of patients and family members, ethics, transmission risks, and laws and regulations governing infectious disease control. Changes in management: The following changes or modifications to CPR strategy in COVID-19 patients are proposed: 1) Healthcare workers should wear PPE. 2) Hands-only chest compression and mechanical chest compression can be implemented to reduce or avoid the spread of viruses by aerosols. 3) Both the benefits to patients and the risk of infection should be considered. 4) Hhealthcare workers should be fully aware of and trained in CPR strategies and procedures specifically for patients with COVID-19.

Objective: To study the effect of rosuvastatin on serum cTnI, CK-MB, Myo, platelet activation and inflammatory factor with acute myocardial infarction after percutaneous coronary intervention(PCI). Methods: A total of 90 patients with acute myocardial infarction in our hospital from January 2013 to January 2016 were enrolled in this study. The subjects were divided into control group (n=45) and treatment group (n=45) randomly. The control group were treated with routine therapy before PCI, the treatment group were treated with rosuvastatincombined with routine therapy before PCI. The serum levels of cTnI, CK-MB, Myo, CD63, CD62p, MPA, TNF-α, hs-CRP and IL-10 of the two groups before and after treatment were compared. Results: There were no significantly differences of the levels of serum cTnI, CK-MB and Myo of the two groups before treatment (P>0.05). The levels of serum cTnI, CK-MB and Myo of the control group after treatment were significantly lower than before treatment (P0.05). The levels of CD63, CD62p and MPA of thetwo groups after treatment were significantly lower than before treatment (P0.05). The levels of serum TNF-α, hs-CRP and IL-10 of the control group after treatment were significantly lower than before treatment (P

BACKGROUND: To investigate the correlation of plasma lncRNA ANRIL expression with stroke risk, severity and inflammatory cytokines levels in acute ischemic stroke (AIS) patients. METHODS: A total of 126 AIS patients and 125 controls were consecutively recruited in this case‐control study. Blood samples from all participants were collected, and plasma was separated. Plasma lncRNA ANRIL expression was quantified by quantitative real‐time polymerase chain reaction (qRT‐PCR). Plasma tumor necrosis factor‐α (TNF‐α) and interleukin (IL)‐1β (IL‐1β), IL‐6, IL‐8, IL‐10, and IL‐17 levels were measured by enzyme‐linked immunosorbent assay (ELISA). National Institutes of Health Stroke Scale (NIHSS) scores were used to assess the stroke severity in AIS patients. RESULTS: Plasma lncRNA ANRIL expression was lower in AIS patients than in controls (P

Objective: The traditional Chinese medicinal puerarin, has long been used to treat cardiovascular diseases, however, the mechanism underlying its effects remain unclear. Here, this study would to investigate the role of puerarin on cardiac angiogenesis and myocardial function induced by myocardial infarction. Methods: Puerarin was treated in rats after left anterior descending coronary artery (LAD) ligation and maintained for 4 weeks (diets containing about 50 mg/kg/day or 100 mg/kg/day). After treatment, cardiac function was evaluated by echocardiography and markers of heart failure. Paraffin sections of the heart tissues were used for isolect in GS-IB4 staining. The Mrna and protein expression levels of VEGFA, Ang-1 and Ang-2 were detected by real-time polymerase chain reaction and western blot. Results: Significantly damaged angiogenesis and slightly increase of VEGFA, Ang-1 and Ang-2 were showed after LAD ligation. Impaired angiogenesis and cardiac function were remarkably improved in puerarin treatment rats with great increase of VEGFA, Ang-1 and Ang-2. Conclusion: The above results demonstrated that puerarin could accelerate cardiac angiogenesis and improve cardiac function of myocardial infarction rats by upregulating VEGFA, Ang-1 and Ang-2.

Objective: The traditional Chinese medicinal berberine has long been used to treat cardiovascular diseases; however, the mechanism underlying its effects remains unclear. Here, this study would to investigate the effects of berberine on proliferation, collagen synthesis and cytokine secretion of cardiac fibroblasts. Methods: We assessed proliferation, collagen synthesis and cytokine secretion in cardiac fibroblasts subjected to angiotensin II (Ang II) subsequent to the consumption of berberine or a control treatment. And then we detected the role of AMPK/mTOR signaling pathway in berberine treatment of cardiac fibroblasts. Results: In the present study, the cellular behaviors of cardiac fibroblasts induced by Ang II were significantly activated including proliferation, transformation into myofibroblasts and collagen synthesis. Additionally, the ability of cytokine secretion was enhanced obviously. It was demonstrated that treatment of cardiac fibroblasts with berberine resulted in deceased proliferation, and attenuated fibroblast α-smooth muscle actin expression and collagen synthesis. And the protein secretion of TGFβ1 was inhibited; however, the protein secretion of IL-10 was increased in cardiac fibroblasts with berberine treatment. Mechanistically, the phosphorylation level of AMPK was increased; and the phosphorylation levels of mTOR and p70S6K were decreased in berberine treatment group. Conclusion: These results illustrated that the protective effects of berberine on cellular behaviors of cardiac fibroblasts were at least in part due to activate AMPK signaling pathway and downregulate mTOR/p70S6K signaling pathway. Berberine might become a new strategy for treating cardiac fibrosis in the future.

Klotho is a novel anti-aging hormone involved in human coronary artery disease. The present study aimed to detect the effects and mechanism of Klotho on cardiomyocytes in a hypoxia/reoxygenation (H/R) model in vitro. Neonatal Sprague-Dawley rat cardiomyocytes were randomly distributed into experimental groups as follows: Control group; H/R group, 4‑h hypoxia followed by 3‑h reoxygenation; and H/R+Klotho group, incubated with 0.1, 0.2 or 0.4 µg/ml Klotho protein for 16 h and then subjected to 4‑h hypoxia/3‑h reoxygenation. In order to evaluate cardiomyocyte damage, cell viability and lactate dehydrogenase (LDH) levels were measured. Cell apoptosis was measured by flow cytometry. The 2',7'-dichlorofluorescein diacetate reagent was used to estimate the intracellular generation of reactive oxygen species (ROS). Immunofluorescence staining was used to test whether Klotho induced decreased nuclear translocation of forkhead box protein O1 (FOXO1). Western blot analysis was performed to detect protein levels of FOXO1, phospho-FOXO1, Akt, phospho-Akt and superoxide dismutase 2 (SOD2). Cell viability was significantly decreased, levels of LDH in the cardiomyocyte culture medium were significantly increased and the apoptotic rate was enhanced in the H/R group when compared with those of the control group. Compared with the H/R group, cell viability of the H/R+Klotho groups was significantly higher (P