Ferroptosis Contributes to Microvascular Dysfunction in Diabetic Retinopathy

Ferroptosis is a new form of cell death characterized by iron-dependent lipid peroxidation. Whether ferroptosis is involved in retinal microvascular dysfunction under diabetic condition is not known. The expression of ferroptosis-related genes in patients with proliferative diabetic retinopathy and in diabetic mice was determined with RT-qPCR. Reactive oxygen species, iron content, lipid peroxidation products, and ferroptosis-associated proteins in the cultured human retinal microvascular endothelial cells (HRMECs) and in the retina of diabetic mice were examined. The association of ferroptosis with the functions of endothelial cells in vitro was evaluated. After administration of ferroptosis-specific inhibitor, Fer-1, the retinal microvasculature in diabetic mice was assessed. Characteristic changes of ferroptosis-associated markers, including GPX4, FTH1, long-chain acyl-CoA synthetase 4, TFRC, and cyclooxygenase-2, were detected in the retinal fibrovascular membrane of patients with proliferative diabetic retinopathy, cultured HRMECs, and the retina of diabetic mice. Elevated levels of reactive oxygen species, lipid peroxidation, and iron content were found in the retina of diabetic mice and in cultured HRMECs. Ferroptosis was found to be associated with HRMEC dysfunction under high-glucose condition. Inhibition of ferroptosis with specific inhibitor Fer-1 in diabetic mice significantly reduced the severity of retinal microvasculopathy. Ferroptosis contributes to microvascular dysfunction in diabetic retinopathy, and inhibition of ferroptosis might be a promising strategy for the therapy of early-stage diabetic retinopathy.

Cost-effectiveness of artificial intelligence screening for diabetic retinopathy in rural China

BACKGROUND

Diabetic retinopathy (DR) has become a leading cause of global blindness as a microvascular complication of diabetes. Regular screening of diabetic retinopathy is strongly recommended for people with diabetes so that timely treatment can be provided to reduce the incidence of visual impairment. However, DR screening is not well carried out due to lack of eye care facilities, especially in the rural areas of China. Artificial intelligence (AI) based DR screening has emerged as a novel strategy and show promising diagnostic performance in sensitivity and specificity, relieving the pressure of the shortage of facilities and ophthalmologists because of its quick and accurate diagnosis. In this study, we estimated the cost-effectiveness of AI screening for DR in rural China based on Markov model, providing evidence for extending use of AI screening for DR.

METHODS

We estimated the cost-effectiveness of AI screening and compared it with ophthalmologist screening in which fundus images are evaluated by ophthalmologists. We developed a Markov model-based hybrid decision tree to analyze the costs, effectiveness and incremental cost-effectiveness ratio (ICER) of AI screening strategies relative to no screening strategies and ophthalmologist screening strategies (dominated) over 35 years (mean life expectancy of diabetes patients in rural China). The analysis was conducted from the health system perspective (included direct medical costs) and societal perspective (included medical and nonmedical costs). Effectiveness was analyzed with quality-adjusted life years (QALYs). The robustness of results was estimated by performing one-way sensitivity analysis and probabilistic analysis.

RESULTS

From the health system perspective, AI screening and ophthalmologist screening had incremental costs of $180.19 and $215.05 but more quality-adjusted life years (QALYs) compared with no screening. AI screening had an ICER of $1,107.63. From the societal perspective which considers all direct and indirect costs, AI screening had an ICER of $10,347.12 compared with no screening, below the cost-effective threshold (1-3 times per capita GDP of Chinese in 2019).

CONCLUSIONS

Our analysis demonstrates that AI-based screening is more cost-effective compared with conventional ophthalmologist screening and holds great promise to be an alternative approach for DR screening in the rural area of China.

Expression of Cx43 and Cx45 in Cardiomyocytes of an Overworked Rat Model

Abstract

Objective To study the effect of overwork stress response on the expression of connexin 43（Cx43） and connexin 45（Cx45） in cardiomyocytes and on cardiac function. Methods The experimental animals were divided into control group, overworked 1-month group and overworked 2-month group. A overworked rat model was established by forcing swimming of overworked group. The expressions of Cx43 and Cx45 in myocardial tissues of experimental animals were detected by Western blotting, while the corresponding myocardial tissues were stained with hematoxylin-eosin （HE） staining and Masson's staining, then histologically observed. Results Western blotting results showed that, compared with the control group, Cx43 expression in myocardial tissues of overworked rats decreased while Cx45 expression increased. HE staining and Masson's staining results showed that hypertrophy, rupture and interstitial fiber tissue hyperplasia were observed in myocardial fibers of overworked rats. Conclusion Overwork stress response may affect cardiac function as an independent factor and may even cause heart failure or arrhythmias and lead to death.

The Concept, Status Quo and Forensic Pathology of Karoshi

Abstract

"Karoshi" originates from Japan's economic take-off period in the 1960s and 1970s. It is generally believed that overwork lead to the accumulation of fatigue, which triggers the outbreak of potential diseases, and results in sudden death. Karoshi causes great harm to both the community and families because it occurs primarily in 30 to 60 year old young adults. Japan put Karoshi into the category of industrial injury for the first time in 2001 and started to undertake a series of studies in the sociological and pathological fields. However, there is a tremendous gap in the forensic pathological diagnosis domain. In China, research on Karoshi started from the 1990s and is closely related to the reform and opening up policy as well as economic development. According to the incomplete statistics, 600 thousand people die from overwork each year in China, the highest in the world. Karoshi has become one of the most serious social problems in China at the present stage, thus a systematic study in the sociology and forensic pathology fields is urgently required. This paper summarizes the past and present status of Karoshi, and puts forward the problems that need attention during the judicial expertise of Karoshi from forensic pathology perspective.

Karoshi May Be a Consequence of Overwork-Related Malignant Arrhythmia

Background

Karoshi, which is sudden death associated with overwork, has become a serious problem in China. Many studies have examined the relationship between cardiovascular risks and karoshi, but there is little evidence that explains the exact mechanism by which overwork induces sudden death. In these cases, there are few obvious positive findings from forensic autopsies except for histories of overwork prior to death. Therefore, we assume that abnormalities, such as cardiac arrhythmia, rather than organic changes are the cause of karoshi.

Material/Methods

In the present study, the forced swim test (FST) was used to establish models of overwork. The myocardial tissues of SD rats taking FST (1 h per day, for 30 consecutive days) were collected. The arrhythmia-related molecule CX43 as well as its upstream regulation molecule Cav-1 and cSrc were tested by Western blot (WB) and immunohistochemistry (IHC). HE staining and Masson‘s staining were performed in the myocardium tissue section.

Results

We observed downregulation of caveolin-1 (Cav1) followed by cSrc activation, resulting in the decrease of connexin43 (Cx43) levels in overwork models. Myocardial interstitial fibrosis, which is associated with electrophysiological aberrances that result in arrhythmia, was also found in the overwork models.

Conclusions

These data provide a mechanistic explanation for the speculated link between karoshi and cardiac arrhythmias.

Advances in exploring the role of microRNAs in the pathogenesis, diagnosis and therapy of cardiac diseases in China

Cardiovascular disease has become the most serious health threat and represents the major cause of morbidity and mortality in China, as in other industrialized nations. During the past few decades, China's economic boom has tremendously improved people's standard of living but has also changed their lifestyle, increasing the prevalence of cardiovascular disease, the so-called 'disease of modern civilization'. This new trend has attracted a significant amount of research. Many of the studies conducted by Chinese investigators are orientated towards understanding the molecular mechanisms of cardiovascular disease. At the molecular level, the long-standing consensus is that cardiovascular disease is associated with a sequence mutation (genetic anomaly) and expression deregulation (epigenetic disorder) of protein-coding genes. However, new research data have established the non-protein-coding genes microRNAs (miRNAs) as a central regulator of the pathogenesis of cardiac disease and a potential new therapeutic target for cardiovascular disease. These small non-coding RNAs have also been subjected to extensive, rigorous investigations by Chinese researchers. Over the years, a large body of studies on miRNAs in cardiovascular disease has been conducted by Chinese investigators, yielding fruitful research results and a better understanding of miRNAs as a new level of molecular mechanisms for the pathogenesis of cardiac disease. In this review, we briefly summarize the current status of research in the field of miRNAs and cardiovascular disease in China, highlighting the advances made in elucidating the role of miRNAs in various cardiac conditions, including cardiac arrhythmia, myocardial ischaemia, cardiac hypertrophy and heart failure. We have also examined the potential of miRNAs as novel diagnostic biomarkers and therapeutic targets.

Cardiovascular research is thriving in China

Cardiovascular disease has become the leading cause of death and constitutes a serious public health issue in China. Faced with the burgeoning epidemic of cardiovascular disease and the huge burden and economic losses it causes, the Chinese government has attached the utmost importance to cardiovascular research, increasing funding to support basic and clinical studies, integrating resources and recruiting outstanding talent from overseas. The continued and growing support from the government has yielded substantial changes in terms of new discoveries, scientific publications and drug research and development within the last decade. In spite of the advances in cardiovascular research, China still faces significant challenges ahead in encouraging innovation, developing the prevention-oriented health policies and strengthening international collaboration.

Ketamine-induced ventricular structural, sympathetic and electrophysiological remodelling: pathological consequences and protective effects of metoprolol

BACKGROUND AND PURPOSE

Growing evidence suggests that long-term abuse of ketamine does harm the heart and increases the risk of sudden death. The present study was performed to explore the cardiotoxicity of ketamine and the protective effects of metoprolol.

EXPERIMENTAL APPROACH

Rats and rabbits were divided into control, ketamine, metoprolol alone and ketamine plus metoprolol groups. Ketamine (40 mg·kg(-1) ·day(-1), i.p.) and metoprolol (20 mg·kg(-1) ·day(-1), p.o.) were administered continuously for 12 weeks in rats and 8 weeks in rabbits. Cardiac function, electrophysiological disturbances, cardiac collagen, cardiomyocte apoptosis and the remodelling-related proteins were evaluated.

KEY RESULTS

Rabbits treated with ketamine showed decreased left ventricular ejection fraction, slowed ventricular conduction velocity and increased susceptibility to ventricular arrhythmia. Metoprolol prevented these pathophysiological alterations. In ketamine-treated rats, cardiac collagen volume fraction and apoptotic cell number were higher than those of control animals; these effects were prevented by co-administration of metoprolol. Consistently, the expressions of poly (ADP-ribose) polymerases-1, apoptosis-inducing factor and NF-κB-light-chain-enhancer of activated B cells were all increased after ketamine treatment and sharply reduced after metoprolol administration. Moreover, ketamine enhanced sympathetic sprouting, manifested as increased growth-associated protein 43 and tyrosine TH expression. These effects of ketamine were prevented by metoprolol.

CONCLUSIONS AND IMPLICATIONS

Chronic treatment with ketamine caused significant ventricular myocardial apoptosis, fibrosis and sympathetic sprouting, which altered the electrophysiological properties of the heart and increased its susceptibility to malignant arrhythmia that may lead to sudden cardiac death. Metoprolol prevented the cardiotoxicity of ketamine, indicating a promising new therapeutic strategy.

Receptor tyrosine kinases as therapeutic targets in malignant glioma

Malignant gliomas have retained their dismal prognosis despite aggressive multimodal conventional therapeutic approaches, illustrating the need for novel therapeutic strategies. Recent advances in the cellular and molecular biology of gliomas have enhanced our understanding of the role of receptor tyrosine kinases (RTK) and RTK-mediated signal transduction pathways in tumor initiation, maintenance, angiogenesis, and vascular proliferation. Special attention has been focused on targets such as epidermal growth factor receptors (EGFR), platelet-derived growth factor receptors (PDGFR), vascular endothelial growth factor receptors (VEGFR), and on pathways such as the Ras/Raf/mitogen-activated protein (MAP)-kinase and phosphatidylinositol-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathways. Novel targeted drugs known as small molecule inhibitors have been shown to modify the activity of these receptors and signaling pathways. Thus far, however, small molecule RTK inhibitor development has concentrated on a few RTK only, and drug activity has been comprehensively evaluated only in a limited number of different malignancies. One of the limiting factors for novel drug design and development is the incomplete knowledge of RTK functions in malignant glioma. This review summarizes current basic and clinical knowledge on the role of RTK in malignant glioma and on their importance as targets for new forms of therapy.

Effects of matrine, artemisinin, tetrandrine on cytosolic [Ca2+]i in guinea pig ventricular myocytes

AIM

To compare the effects of matrine, artemisinin, and tetrandrine on intracellular Ca2+ concentration ([Ca2+]i) in guinea pig ventricular myocytes.

METHODS

A single ventricular myocyte was loaded with Fluo 3-acetoxymethyl (Fluo 3-AM). [Ca2+]i was recorded by laser scanning confocal microscope and represented by fluorescence intensity (FI).

RESULTS

1) KCl 60 mmol . L-1 elevated the FI from 299 +/ -19 to 1389 +/- 325 (P < 0.01) in the presence of extracellular Ca2+ 1.8 mmol . L-1. 2) Both matrine and artemisinin at the concentration of 100 micromol . L-1 could enhance the increase of FI by KCl 60 mmol . L-1. The FI values reached 1495 +/- 320 and 1646 +/- 308 from 301 +/- 14 and 299 +/- 16 (P < 0.01), respectively. 3) Both tetrandrine 1, 10, and 100 micromol . L-1 and verapamil 10 micromol . L-1 inhibited the influx of extracellular Ca2+ induced by KCl 60 mmol . L-1. 4) Matrine 1, 10, and 100 micromol . L-1 could elevate the FI in the presence of extracellular Ca2+. The FI values reached 441 +/- 96, 504 +/- 112, and 643 +/- 126 from 303 +/- 27, 300 +/- 32, and 296 +/- 19 (P < 0.05), respectively. 5) Tetrandrine 1 and 10 micromol . L-1 could apparently inhibited Ca2+ release from intracellular calcium stores induced by caffeine 20 mmol . L-1 (P < 0.05).

CONCLUSION

Effects of matrine, artemisinin, and tetrandrine on [Ca2+ )]i in ventricular

[Effects of fluid percussion injury on intracellular [Ca2+]i and pH in cultured rat neurons]

AIM

To study the change of intracellular [Ca2+]i and pH in cultured neurons after fluid percussion injury, and the therapeutic effect of drugs.

METHODS

The neurons of Sprague Dawley rats were cultured for 8-14 days, then treated them with fluid percussion injury (2.5 kPa, 20 ms). Alterations of [Ca2+]i and pH in single neural cells following fluid percussion injury were measured by a laser scanning confocal microscope. After being injured for several hours the cultured neurons were treated with nimodipine or D-(-)-2-amino-5-phosphonovaleric acid (D-AP-5). Two hours later, the effects of drugs on intracellular [Ca2+]i and pH were studied.

RESULTS

The Intracellular [Ca2+]i increased quickly after brain injury and reached peak in 12 hours. It then decreased gradually and became normal at 48 hours. The pH decreased slowly, reached minimum in 12 hours, and then kept at a lower level. It did not recover normal at 48 hours. Nimodipine and D-AP-5 decreased significantly the ascension of [Ca2+]i and the descent of pH. But nimodipine and D-AP-5 must be given within 10 hours after injury for a good therapeutic effect.

CONCLUSION

According to the change of intracellular [Ca2+]i and pH, early use of nimodipine and D-AP-5, will get a better therapeutic effect.

Effects of erysimin G on renal tubular function and 70-pS K+ channel activity of thick ascending limb

AIM

To study the effect of erysimin G (CH35H52O13) on the thick ascending limb (TAL) 70-pS K+ channel of rat kidney and its effect on diuresis.

METHODS

The patch-clamp cell-attached recording technique was used to record the single potassium channel current, and the urine volume (UV) was measured by urethral intubation to determine the diuretic effect.

RESULTS

Erysimin G can increase the urine volume and decrease the 70-pS potassium channel activity of TAL.

CONCLUSION

Erysimin G has a diuretic effect and its inhibition on the activity of apical 70-pS potassium channel may be the mechanism of its diuretic effect.

Inhibitory effects of berberine on IK1, IK, and HERG channels of cardiac myocytes

AIM

To study the effects of berberine on inward rectifier potassium current (IK1) and outward delayed rectifier potassium current (IK) of guinea pig ventricular myocytes, and on human ether-a-go-go related gene (HERG) channel expressed in Xenopus oocytes.

METHODS

Whole cell patch-clamp and geneclamp techniques were used to record ionic currents.

RESULTS

Berberine prolonged action potential duration (APD) and inhibited IK1 and IK in a concentration-dependent manner. Berberine 100 micromol/L increased APD90 from (450 +\- 48) ms to (888 +\- 90) ms (n = 6, P < 0.01), and inhibited IK1 by 65 % +\- 7 % (n = 6, P < 0.01). Berberine 50 micromol/L inhibited IK by 57 % +\- 6 %, IKtail by 53 % +\- 6 % (n = 6, P < 0.01). Berberine produced a voltage-dependent block on IK that increased with stronger depolarization, and once all channels were activated, there was no further block at positive potentials. Berberine blocked the HERG channels potently with an IC50 value of approximately 75 micromol/L. This block was voltage-dependent, suggesting that it probably bind to either open or inactivated HERG channels.

CONCLUSION

Berberine prolonged APD and possessed blocking effect on IK1, IK, and HERG channel expressed in Xenopus oocytes. The antiarrhythmic mechanism of berberine is related to its inhibitory effects on IK1, IK, and HERG channel.

[Cardiac-hemodynamic effects of M3 receptor agonist on rat and rabbit hearts]

AIM

To study the activation of choline on M3-R in heart and observe the hemodynamic changes of rat and rabbit.

METHODS

A cardiac catheter was inserted into the left ventricular cavity via the right carotid artery, then the HR, LVSP, LVEDP, and +/- dp/dt were measured using a polygraph system.

RESULTS

Choline was shown to decrease the hemodynamic assessments, such as HR, + dp/dt, LVSP and LVEDP. while the M3-R antagonist 4-DAMP (4-diphenylacetoxy-N-methylpiperidine-methiodide) showed little effect on these assessments. It was found to reverse the hemodynamic effects of choline.

CONCLUSION

M3 receptor agonist can produce negative inotropic and chronotropic effects on the heart of rat and rabbit.

[Inhibition of transmembrane K(+) currents in mammalian ventricular myocytes by antiarrhythmic agent RP62719]

The effect of RP62719 on the inward rectifier K(+) current (I(K1)),transient outward K(+) current (I(to)) and delayed outward K(+) current (I(K)) in isolated cardiac myocytes was determined using the whole cell patch clamp technique in guinea pig and dog. RP62719 decreased I(K1) with an inhibitory concentration 50 (IC(50) ) of 5.0+/-1.0 micromol/L at -100 mV in guinea pig ventricular cells. In dog ventricular myocytes, RP62719 inhibited Ito by 84+/-4.4% with an IC(50) of 1.2+/-0.51 micromol/L at +40 mV. In guinea pig ventricular cells, RP62719 decreased I(K): I(Kstep) by 50.0+/-8.3%%and I(Ktail) by 56.0+/-4.9% at +40 mV, respectively. RP62719 inhibited I(Kstep) with an IC(50) of 4.2+/-0.8 micromol/L and I(Ktail) with an IC(50) of 3.3+/-0.75 micromol/L. Thus it is suggested that the ionic mechanism of antiarrhymic effect by RP62719 may be due to its inhibition of I(K1),I(to) and I(K).

Effects of RP58866 on transmembrane K+ currents in mammalian ventricular myocytes

AIM

To determine effects of RP58866 on inward rectifier K+ current (IKl), transient outward K+ current (Ito) and delayed outward rectifier K+ current (IK) in isolated cardiac myocytes.

METHODS

In isolated ventricular myocytes of guinea pig and dog, the effect of RP58866 on IKl, Ito, and IK were observed by the whole cell voltage-clamp technique.

RESULTS

RP58866 decreased IKl in a concentration-dependent manner, with an IC50 of (3.4 +/- 0.8) micromol.L-1 (n = 6) at -100 mV in guinea pig ventricular cells. In dog ventricular myocytes, RP58866 inhibited Ito with IC50 of (2.3 +/- 0.5) micromol.L-1 at +40 mV. In guinea pig ventricular cells, RP58866 at 100 micromol.L-1 decreased IK: IKstep by (58 +/- 13)% at +40 mV, and IKtail by (86 +/- 17)%, respectively. RP58866 inhibited IKstep with an IC50 of (7.5 +/- 0.8) micromol.L-1, and IKtail with an IC50 of (3.5 +/- 0.9) micromol.L-1. The envelope of tail analysis suggested that both IKr and IKs were inhibited.

CONCLUSION

RP58866 inhibits IKl, Ito, and IK in cardiac myocytes with a similar potency, and is not a specific IKl inhibitor.

Artemisinin blocks activating and slowly activating K+ current in guinea pig ventricular myocytes

AIM

To study the effect of artemisinin (Art) on outward rectifier potassium current in ventricular myocytes.

METHODS

In isolated guinea pig ventricular myocytes, the effects of Art on the two components of delayed outward rectifier K+ current (IK), the rapidly activating inward K+ current (IKr), and the slowly rectifying outward K+ current (IKs) were observed by the whole cell patch-clamp technique.

RESULTS

Art decreased IK in a concentration-dependent manner. The IKstep and IKtail were reduced from 387 +/- 46 pA to 240 +/- 48 pA and from 299 +/- 30 pA to 130 +/- 38 pA, respectively at holding potential of +40 mV by Art 50 mumol.L-1. The envelope of tail analysis suggested that both IKr and IKs were inhibited.

CONCLUSION

Art blocked the two components of delayed outward rectifier K+ current (IKr and IKs) in guinea pig ventricular cells.

Inhibitory effect of tetrahydropalmatine on calcium current in isolated cardiomyocyte of guinea pig

AIM

To study the effect of tetrahydropalmatine (THP) on calcium channels in ventricular single cells of guinea pig heart.

METHODS

Patch-clamp technique (whole cell recording) was used to observe calcium current in ventricular myocytes.

RESULTS

THP decreased ICa in ventricular myocytes with a dose and frequency-dependent manner. THP (0.1, 1, and 10 mumol.L-1) decreased ICa from 1.15 +/- 0.22, 0.91 +/- 0.18, and 1.60 +/- 0.42 nA (control) to 0.9 +/- 0.21 (P < 0.01), 0.56 +/- 0.21 (P < 0.01), and 0.83 +/- 0.21 nA (P < 0.05), respectively, number of cells is five in each group (n = 5), and the rates of the depression of ICa were 22%, 38%, and 48%, respectively. The effect was easily reduced by washing the cell with the Tyrode's solution. The current-voltage relation curve showed that the potential producing peak value of ICa was 0 mV at which THP had the most markedly inhibited action on ICa. When the stimulating frequency was changed, ICa varied in a frequency-dependent manner 5 min after THP was given, and the inhibition of THP was stronger at 2 Hz than that at 0.1 Hz.

CONCLUSION

THP possessed a Ca2+ channel blocking effect.

Frequency- and voltage-dependent inhibition of delayed outward potassium current by flecainide in isolated atrial cell of guinea pig heart

Effects of flecainide (Fle) on membrane currents were studied using an isolated single atrial cell from guinea pig hearts. The tight-seal cell clamp technique was used. In the current clamp condition, Fle prolonged significantly the atrial action potential (APD) with frequency dependence. Delayed outward K+ current and outward tail current were specifically inhibited by Fle in a frequency- and concentration-dependent fashion. Fle inhibited Ik more strongly as the membrane potential became more positive from +10 mV to +60 mV. The value of Ik was attenuated to 973 pA from 1105 pA of control and the value of tail current was reduced to 113 pA from 288 pA of control at 60 mV. The drug did not affect the holding current. The effects of Fle on the action potential and transmembrane ionic currents strongly suggested that the main mechanism of action of this agent was to inhibit the voltage-dependent potassium current. In the voltage clamp condition, Fle affected neither the conventional L type Ca2+ current nor the Ik1 current significantly. Our research proved that Fle was not completely consistent with the class Ic agents, because Fle could markedly increase the APD in the experiment.

Effects of berbamine on hemodynamics and myocardial reperfusion injury in isolated working rabbit hearts

The isolated working rabbit hearts perfused with Tyrode's buffer solution persisted working in good condition at least up to 70 min. Berbamine (Ber) 3 mumol.L-1 significantly changed the hemodynamic parameters and reduced cardiac functions. The effects of Ber appeared in a dose-dependent manner. Reperfusion following 30-min of global ischemia aggravated the myocardial damages induced by ischemia, and the parameters of cardiac functions in working hearts markedly reduced and did not restore even at 20 min of reperfusion. Ber 1 mumol.L-1 reduced the myocardial ischemic reperfused damages and restored all parameters to the level of preischemia within 10 min of reperfusion, and this situation of working hearts also lasted 40-50 min. The present results showed that Ber could protect myocardium against ischemic reperfused damages, promote the recovery of cardiac functions and prolong the efficient working period in isolated working rabbit hearts.