Development of an energy spread analyzer for secondary ion mass spectrometry ion source.

The energy spread (ΔE) of an ion source is an important parameter in the production of a finely focused primary ion beam applied in secondary ion mass spectrometry (SIMS). A variable-focusing retarding field energy analyzer (RFEA) has been developed and tested with an Ar+ beam and an oxygen ion beam extracted from a 2.45 GHz microwave ion source, which is developed as a candidate ion source for SIMS applications. The simulation results show that the relative resolution ΔE/E of the designed RFEA reaches 7 × 10-5. The experimental results indicate that a focusing electrode can improve the ΔE measurement results, which is consistent with the simulation results. The ion energy distributions of the Ar+ beam and oxygen ion beam are of Gaussian distribution with the value of ΔE of 3.3 and 2.9 eV, respectively. These results indicate that the designed RFEA is reliable for measuring the ion beam energy spread. The developed RFEA is also used to study the plasma behavior in different settings, which reveals that plasma stability is critical to making a low energy spread ion beam. This paper will present the simulation, design, and test of the variable-focusing RFEA. Preliminary ion beam quality studies with this instrument will also be discussed.

A compact radio-frequency ion source for high brightness and low energy spread negative oxygen ion beam production.

A high brightness and low energy spread (∆E) ion source is essential to the production of a high-quality primary ion beam applied in secondary ion mass spectrometry (SIMS). A compact 13.56 MHz radio-frequency (RF) ion source with an external planar spiral antenna has been developed as a candidate ion source for the production of negative oxygen ion beams for SIMS application. This ion source is designed with a three-and-a-half-turn water-cooled planar antenna for RF power coupling, a multi-cusp magnetic field for effective plasma confinement, and a three-electrode extraction system. The experimental results show that more than 50 µA negative oxygen ion beams have been extracted, which consist of 56% O-, 25% O2-, and 19% O3-. The ion energy distribution of the negative oxygen ion beam exhibits a Gaussian distribution with a minimum ∆E of 6.3 eV. The brightness of the O- beam is estimated to be 82.4 A m-2 Sr-1 V-1. The simulation, design, and experimental study results of this RF ion source will be presented in this paper.

A minimized and efficient low temperature loading device for indentation.

A minimized and efficient low temperature loading device cooling with Peltier coolers for indentation test is developed. Both specimen and indentation tip are immersed in 50% methanol-water solution, totally eliminating the contact thermal drift problem. Low temperature indentation tests down to 253.8 K can be realized within 10 min. The size of the device is miniaturized within 50 × 40 × 30 mm3, and no vacuum environment is required. Monocrystalline copper is tested to perform the feasibility of the device. Based on the simple structure and stable experimental effect, the developed device can be integrated into various types of current indentation devices to attach low temperature testing ability.

[Study on the correlation between PPG and HVPG in patients with portal hypertension].

Objective: To explore the correlation between portal vein pressure gradient (PPG) and hepatic vein pressure gradient (HVPG) in patients with portal hypertension (PHT). Methods: 752 cases with portal hypertension (PHT) who underwent transjugular intrahepatic portosystemic shunt (TIPS) and met the enrollment criteria between January 2016 to December 2019 were analyzed for hepatic vein, inferior vena cava and portal vein pressure. Paired t-test was used for analysis. Pearson correlation test was used to estimate correlation coefficient and coefficient of determination. P<0.05 were considered statistically significant. Results: Wedged hepatic vein pressure (WHVP), portal vein pressure (PVP), correlation coefficient, and coefficient of determination were 27.98±8.95 mmHg, 33.85±7.33 mmHg, 0.329 (P<0.001), and 0.108, respectively. HVPG, PPG,correlation coefficient, and coefficient of determination were 16.84±7.97 mmHg, 25.11±6.95 mmHg (P<0.001), 0.145, and 0.021 (P<0.001), respectively. The difference between HVPG and PPG was greater than 5 mmHg in 524 cases, accounting for 69.7%. The difference between HVPG and PPG was within 5 mmHg or basically equal in 228 cases, accounting for 30.3%. The correlation coefficient between free hepatic venous pressure (FHVP) and inferior vena cava pressure (IVCP) was 0.568 (P<0.001), and the coefficient of determination was 0.323. According to the presence or absence of hepatic venous collaterals after balloon occluded hepatic angiography, they were divided into two groups: 157 (20.9%) cases in the group with hepatic venous collaterals, and 595 (79.1%) cases in the group without hepatic venous collaterals. The parameters of the two groups were compared: WHVP (15.73±3.63) mmHg vs. (31.22±6.90) mmHg, P<0.001; PVP (31.69±8.70) mmHg vs. (34.42±6.81) mmHg, P<0.001; HVPG (7.18±4.40) mmHg vs. (19.40±6.62) mmHg, P<0.001; PPG (24.24±8.11) mmHg vs. (25.34±6.60) mmHg, P<0.001; free hepatic venous pressure (FHVP) (8.58±3.37) mmHg vs. (11.82±5.07) mmHg , P<0.001; inferior vena cava pressure (IVCP) (7.45±3.29) mmHg vs. (9.09±4.14) mmHg, P<0.001. Conclusion: The overall correlation is poor between HVPG and PPG. HVPG of most patients is not an accurate representation of PPG, and the former is lower than the latter. Hepatic venous collateral formation is one of the important reasons for the serious underestimation of HVPG values.

[Analysis of 53 cases of transjugular liver biopsy].

Objective: To investigate the practicability and safety of transjugular liver biopsy (TJLB). Methods: Data of 53 cases with transjugular liver biopsy from June 2015 to June 2020 were collected. LABS-100 was used in all patients who underwent transjugular liver biopsy. Among them, 45 cases and eight were biopsied via hepatic vein and intrahepatic segment of the inferior vena cava. The surgical indications, related complications, and postoperative pathological diagnosis were analyzed and summarized. Results: TJLB was successful in all patients, with an average of 2.8 punctures per case. Satisfactory liver tissue and histopathological diagnosis was obtained in all patients. Two cases developed a cervical hematoma that was improved spontaneously, and one patient developed an intrahepatic hematoma that was improved after conservative treatment. Conclusion: TJLB is a practical and safe method for patients with contraindications to percutaneous liver biopsy.

[Comparison of hereditary breast and ovarian cancer syndrome and sporadic ovarian cancer in ovarian cancer BRCA mutations].

Objective: To study the difference between BRCA gene mutations in hereditary breast and ovarian cancer syndrome (HBOC) and in sporadic ovarian cancer (SOC). Methods: This study was for exploratory research, the inclusion criteria were 284 patients with ovarian cancer admitted at Shanxi Provincial Cancer Hospital from November 2018 to December 2019, with high-throughput DNA sequencing including the full coding regions and exon-intron link regions of BRCA1 and BRCA2 gene. Pathogenic mutations in the BRCA gene of patients with ovarian cancer were collected and mutation site analysis was performed to compare phenotypic differences in pathogenic mutations between HBOC syndrome and SOC patients. Results: (1) Of the 284 ovarian cancer patients, seventy-seven had BRCA pathogenic mutations with a mutation rate of 27.1% (77/284), with BRCA1 mutation rate of 19.7% (56/284), BRCA2 gene 6.7% (19/284) and BRCA1/2 common mutation rate of 0.7% (2/284). Of the 284 patients with ovarian cancer, the pathogenic mutation rate in the BRCA gene in HBOC syndrome patients was 43.8% (32/73), which were significantly higher than that in SOC patients [21.3% (45/211); χ²=13.905, P<0.01]. Among BRCA1 gene mutation, the mutation rate in HBOC syndrome was higher than that of SOC [87.5% (28/32) vs 62.2% (28/45)], the BRCA2 gene mutation rate in patients with HBOC syndrome was lower than that in SOC patients [6.2% (2/32) vs 37.8% (17/45)], and there were statistically significant differences (all P<0.05). Two of the 77 patients with pathogenic mutations in the BRCA gene were multisite mutations, including one simultaneous two site mutation, one simultaneous three site mutation. There were 80 mutation sites with frameshift deletion mutations (55.0%, 44/80) and nonsense mutations (31.2%, 25/80). (2) Of the 73 patients with HBOC syndrome, 32 cases had pathogenic mutations in BRCA gene, including 28 cases in BRCA1, mainly in exon 11 and 24 (9 and 7 cases, respectively), and only two cases in BRCA2, both in exon 11; another two had multiple locus mutations. Of the 211 patients with SOC, 45 cases had pathogenic mutants in BRCA gene, including 28 cases in BRCA1, mainly in exon 11 and 24 (15 and 2 cases, respectively), and 17 cases in BRCA2, mainly in exon 11 (11 cases). (3) Thirty-four pathogenic mutation sites in BRCA gene were found newly, twenty of them were located in the BRCA1 gene, including a locus located on the intron 6, 301+1G>A, and the remaining 19 sites were located on the exons, including 283_286delCTTG, 68_69delAG, 132C>T, 514_547+3del37, 742delA, 1126_1129delAATA, 1196delA, 1352_1364del, 1465G>T, 2171delC, 2341G>T, 3359_3363delTTAAT, 4085_4086ins11, 4161_4162delTC, 4165_4166delAG, 4258G>T, 4338_4339del8insAGAA, 4468G>T, and 4783delA; fourteen sites were located in the BRCA2 gene, including a locus located on the intron 7, 631+1G>A, and the remaining 13 sites were located on the exons, including 2648delT, 2914A>T, 2950_2951insG, 4357+1G>A, 5054C>T, 5257A>T, 5291_5292insTC, 5913delT, 3593delA, 6091_6092insA, 6135_6136delTT, 7452delT, 9097_9098insA. A tal of 28 repeat mutations were located in the BRCA1 gene; among them, the site 5470_5477del8 was repeated 6 times, while 3 times in 981_982delAT. Conclusions: Patients with HBOC syndrome have a significantly higher rate of pathogenic mutation in the BRCA gene than that in patients with SOC. BRCA gene pathogenic mutation sites in HBOC syndrome patients occur commonly in exon 11 and 24 of BRCA 1 gene, while SOC patients occur mainly in exon 11 and 24 of BRCA1 gene and exon 11 of BRCA2 gene. The two loci of BRCA1∶5470_5477del8, BRCA1∶981_982delAT may be ancestor mutations in Chinese ovarian cancer patients, and 34 newly discovered pathogenic mutations in the BRCA gene, enriching the BRCA gene mutation spectrum in the Chinese population.

Direct Measurement of the Astrophysical

Fluorine is one of the most interesting elements in nuclear astrophysics, where the ^{19}F(p,α)^{16}O reaction is of crucial importance for Galactic ^{19}F abundances and CNO cycle loss in first generation Population III stars. As a day-one campaign at the Jinping Underground Nuclear Astrophysics experimental facility, we report direct measurements of the essential ^{19}F(p,αγ)^{16}O reaction channel. The γ-ray yields were measured over E_{c.m.}=72.4-344 keV, covering the Gamow window; our energy of 72.4 keV is unprecedentedly low, reported here for the first time. The experiment was performed under the extremely low cosmic-ray-induced background environment of the China JinPing Underground Laboratory, one of the deepest underground laboratories in the world. The present low-energy S factors deviate significantly from previous theoretical predictions, and the uncertainties are significantly reduced. The thermonuclear ^{19}F(p,αγ)^{16}O reaction rate has been determined directly at the relevant astrophysical energies.

Production of metallic ion beams by electron cyclotron resonance ion sources equipped with inductive heating ovens at the Institute of Modern Physics.

A high-temperature oven based on the inductive heating technology was developed successfully at the Institute of Modern Physics in 2019. This oven features a durable operation temperature of over 2000 °C inside the tantalum susceptor. By carefully designing the oven structure, the material compatibility issue at high temperature has been successfully solved, which enables the production and routine operation of refractory metal ions with SECRAL-II (Superconducting Electron Cyclotron Resonance ion source with Advanced design in Lanzhou No. 2). To further apply this type of oven to the room temperature ECR ion sources LECR4 and LECR5 (Lanzhou Electron Cyclotron Resonance ion source No. 4 and 5), a mini-inductive heating oven has been fabricated and tested in 2020. By directly evaporating calcium oxide, some high charge state calcium beams have been produced successfully, such as 52 euA of 40Ca16+, 30 euA of 40Ca17+, and 12 euA of 40Ca18+. The detailed design and testing results will be presented and discussed.

Influence of electron cyclotron resonance ion source parameters on high energy electrons.

In order to diagnose the electron cyclotron resonance (ECR) plasma, a high-efficiency collimation system has been developed at the Institute of Modern Physics, and the bremsstrahlung spectra in the range of 10 keV-300 keV were measured on a third generation superconducting ECR ion source, SECRAL-II, with a CdTe detector. Used as a comparative index of the mean energy of the high energy electron population, the spectral temperature, Ts, is derived through a linear fitting of the spectra in a semi-logarithmic representation. The influences of some main source parameters, such as the neutral gas pressure, extraction voltage, microwave power, and bias disk voltage, on the high energy electrons are systemically investigated.

[Predictive value of vascular health indicators on newly cardiovascular events: Preliminary validation of Beijing vascular health stratification system].

OBJECTIVE: To explore the predictive value of carotid femoral artery pulse wave velocity (CF-PWV), carotid radial artery pulse wave velocity (CR-PWV), cardio-ankle vascular index (CAVI), and ankle brachial index (ABI) on coronary heart disease (CHD) and cerebral infarction (CI), and the preliminary validation of Beijing vascular health stratification (BVHS). METHODS: Subjects with at least 2 in-patient records were included into the study between 2010 and 2017 from Vascular Medicine Center of Peking University Shougang Hospital. Subjects with CHD or CI, and without data of vascular function at baseline were excluded. Eventually, 467 subjects free of CHD [cohort 1, mean age: (63.4±12.3) years, female 42.2%] and 658 subjects free of CI [cohort 2, mean age: (64.3±12.2) years, female 48.7%] at baseline were included. The first in-patient records were as the baseline data, the second in-patient records were as a following-up data. Cox proportional hazard regression was used to establish the predictive models of CHD or CI derived from BVHS by multivariable-adjusted analysis. RESULTS: The median follow-up time of cohort 1 and cohort 2 was 1.9 years and 2.1 years, respectively. During the follow-up, 164 first CHD events occurred in cohort 1 and 117 first CI events occurred in cohort 2. Four indicators were assessed as continuous variables simultaneously by multivariable-adjusted analysis. In cohort 1, CF-PWV, CR-PWV, ABI, and CAVI reached statistical significance in the multivariable-adjusted models (P<0.05). In cohort 2, only CAVI (P<0.05) was of statistical significance. In addition, the higher CF-PWV became a protector of CHD or CI (P<0.05). The prediction value of BVHS reached the statistical significance for CHD and CI in the unadjusted models (all P<0.05), however, BVHS could only predict the incidence of CHD (P<0.05), but not the incidence of CI (P>0.05) in the multivariable-adjusted models. CF-PWV, CR-PWV, ABI, and CAVI were associated factors of CHD independent of each other (P<0.05), only CAVI (P<0.05) was the risk factor of CI independent of the other three. CONCLUSION: The different vascular indicators might have different effect on CHD or CI. CAVI might be a stable predictor of both CHD and CI. Higher baseline CF-PWV was not necessarily a risk factor of CHD or CI because of proper vascular health management. BVHS was a potential factor for the prediction of CHD, and further research is needed to explore the prediction value for CI.

Metformin reduces pancreatic cancer cell proliferation and increases apoptosis through MTOR signaling pathway and its dose-effect relationship.

OBJECTIVE: To study the influences of metformin on the proliferation and apoptosis of pancreatic cancer cells and its dose-effect relationship and crucial molecular mechanism. MATERIALS AND METHODS: With human pancreatic cancer cell line PANC-1 as the study object, different concentrations of metformin were added for intervention. Then, the proliferation of PANC-1 cells was detected via methyl thiazolyl tetrazolium (MTT) assay to determine the dose-effect relationship of metformin in PANC-1 cell proliferation. PANC-1 cells were treated with metformin at three appropriate concentrations as Metformin treatment groups, and an equal amount of dimethyl sulfoxide (DMSO) was added in Control group. Flow cytometry was performed to detect PANC-1 cell cycle and apoptosis, and the apoptosis of PANC-1 cells was also evaluated via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Caspase-3 protein localization and expression in PANC-1 cells were detected using immunofluorescence assay. Besides, the expressions of the apoptosis-associated proteins Caspase-3, B-cell lymphoma 2 (Bcl-2), and Bcl-2 associated X protein (Bax) and phosphatidylinositol 3-hydroxy kinase (PI3K), phosphorylated protein kinase B (p-Akt), and p-mammalian target of rapamycin (mTOR) proteins related to the mTOR pathway were detected using Western blotting. RESULTS: Metformin repressed the proliferation of human pancreatic cancer PANC-1 cells in a concentration-dependent and time-dependent manner. Compared with Control group, Metformin treatment groups (0, 20 and 40 mM) exhibited a higher proportion of PANC-1 cells in G0/G1 phases, and a lower proportion of PANC-1 cells in S phase (p<0.05), and the change in the proportion of cells in G2/M phase was not statistically significant (p>0.05). Moreover, Metformin treatment groups (0, 20, and 40 mM) had more apoptotic PANC-1 cells, higher expression levels of pro-apoptosis proteins Caspase-3 and Bax and lower expression levels of anti-apoptosis protein Bcl-2 and the mTOR pathway-related proteins PI3K, p-Akt, and p-mTOR in cells than Control group (p<0.05). CONCLUSIONS: Metformin modulates the mTOR signaling pathway to reduce the proliferation of pancreatic cancer cell, but increase their apoptosis.

Overview of high intensity ion source development in the past 20 years at IMP.

Ion source development over the last 20 years at the IMP is reviewed. For versatile purposes, several types of ion sources have been involved in the research and development work at the IMP, i.e., the highly charged ECR (Electron Cyclotron Resonance) ion source, intense microwave ion source or the 2.45 GHz intense beam ECR ion source, and laser ion source (LIS). In the development of ECR ion sources, SECRAL (Superconducting ECR ion source with Advanced design in Lanzhou), Lanzhou ECR ion source, and Lanzhou all permanent magnet ECR ion source series have been made, which can cover the operation microwave frequency range of 10-28 GHz. The LIS with an Nd:YAG laser with a maximum output energy of 8 J in 8 ns pulse duration has been developed for very intense short pulse ion beams from solid materials such as C, Ti, Ni, Ag, and so on. Microwave ion sources have been built to produce intense pulsed or direct current beams from several mA to 100 mA for either high intensity accelerators or applications. This paper will give an overview of the high intensity ion source development at the IMP, especially on the recent progress and new results, such as the status of the fourth generation ECR ion source (first fourth generation ECR ion source), the production of recorded highly charged ion beams with SECRAL sources, key technology research studies, and so on.

A new room temperature LECR5 ion source for the SESRI project.

The Space Environment Simulation and Research Infrastructure project, which uses various ion beams as irradiated materials in life science research, is being built at the Harbin Institute of Technology. A new room temperature electron cyclotron resonance ion source, the Lanzhou Electron Cyclotron Resonance Ion Source No. 5 (LECR5), has been designed and constructed. It is an intense, highly charged, heavy ion beam injector which generates ion beams from H to Bi, typically ∼50 eµA 209Bi32+. The LECR5 is designed to operate at microwave frequencies in the range of 14.5-18 GHz. The typical magnetic parameters are designed based on those optimized for SECRAL, which operates at 18 GHz. This paper presents the LECR5 ion source, its test bench, and the preliminary beam results.

Intense carbon beams production with an all permanent magnet electron cyclotron resonance ion source for heavy ion medical machine.

LAPECR3 (Lanzhou All Permanent magnet Electron cyclotron Resonance ion source No. 3) had been developed as an ion injector of Heavy Ion Medical Machine (HIMM) accelerator facility since 2009. The first HIMM accelerator facility was built in Wuwei city in 2015, and the LAPCER3 ion source has delivered C5+ ion beam to HIMM for more than 1000 days in the past four years. In order to improve the performance of the LAPECR3 ion source for intense carbon beams production, continuous research and development work has been made. The recently developed LAPECR3 ion source together with the new low-energy beam transportation can provide better performance in terms of both beam intensity and quality. This paper will generally review the LAPECR3 ion source operation status for HIMM, and the recent improvement will be presented, especially the stable beams production of C4+ and C5+.

Emittance study of the high intensity highly charged heavy ion beams extracted from electron cyclotron resonance ion source.

According to the requirements of ion beams extracted from an electron cyclotron resonance ion source transverse phase space coupling research and the afterglow beam property effective measurement, a pepper pot type meter called PEMiL (Pepper Pot Emittance Meter in Lanzhou) has been designed, fabricated, and commissioned to obtain the emittance of high intensity highly charged heavy ion beams. The direct current beam emittance measurement results verify the coupling property caused by the semisolenoid field. This paper also describes the scheme of multiple exposure accumulation which was applied to measure the afterglow beam property, and the transverse phase space distribution of the oxygen afterglow beam which was measured for the first time is presented.

A new microwave coupling scheme for high intensity highly charged ion beam production by high power 24-28 GHz SECRAL ion source.

The efficiency of the microwave-plasma coupling is a key issue to enhance the performance of electron cyclotron resonance ion sources (ECRISs) in terms of higher ion beam intensity yield. The coupling properties are affected by the microwave coupling scheme, especially for the high frequency (f > 20 GHz) and high power (P > 5 kW) ECR ion sources. Based on the study of 24 GHz SECRAL ion source performances working at different launching systems, a new microwave coupling scheme, called the Vlasov launcher, is proposed, which can not only realize efficient power matching and feeding but also enhance the microwave power distribution on the ECR surface. The first promising results are presented in this article. Then, a prototype dedicated to the next generation ECRIS is described.

Laser ablation plasma with solenoid field confinement.

A Laser Ion Source (LIS) can produce high charge state and high intensity ion beams (∼emA), especially, refractory metallic ion beams, which makes it a promising candidate as an ion source for heavy ion cancer therapy facilities and future accelerator complexes, where pulsed high intensity and high charged heavy ion beams are required. However, it is difficult for the LIS to obtain a long pulse width while ensuring high current intensity, thus limiting the application of the LIS. To solve the conflict, magnetic fields are proposed to confine the expansion of the laser produced plasma. With a solenoid along the normal direction to the target surface, the lateral adiabatic expansion of the laser ablation plasma is suppressed which extends the pulse width of the ion beam effectively. The characteristics of laser ablation plasma with solenoid field confinement will be presented and discussed in this paper.

Production of intense uranium beams with inductive heating oven at Institute of Modern Physics.

HIAF (High Intensity heavy ion Accelerator Facility) is a new accelerator complex under construction at the Institute of Modern Physics. As the main injector of this project, the high-charge-state ECR ion source needs to provide intense uranium beams, such as 700 eµA of U35+. This requires the performance of metal ovens to be further improved so that the crucible can operate at an ultrahigh temperature for a long time without damage in a high magnetic field (>3 T). In order to meet these requirements, an inductive oven with special thermal shielding and support has been developed in the past two years. The off-line test result has shown that this oven can reach up to 2000 °C with ∼1.2 kW of heating power. After ∼5 days of continuous running on the SECRAL-II platform, the tantalum crucible survived. In this contribution, we will discuss the structure of this inductive oven and analyze the test results as well.

Production of O- and O2 - beams with the negative ion source at Institute of Modern Physics.

A negative oxygen ion source is under development to produce O- and O2 - beams used for a secondary ion mass spectrometer at Institute of Modern Physics (IMP), and both filament and radio frequency (RF) schemes are tested. The filament driven ion source, which was initially designed for H- production, has a 10-pole multicusp plasma chamber, two sets of virtual magnetic filters, and a 3-electrode extraction system. The RF scheme, which is improved by changing a RF back plate from the filament ion source, has an external planar spiral RF antenna behind an AlN window. The RF power system consists of a continuous wave (CW) 13.56 MHz/2 kW power supply, a capacitive automatching network and a water-cooled flat RF antenna made from a 6-mm copper tube. Oxygen and carbon dioxide gases are used to produce O- and O2 - ion beams, and ion composition is analyzed by using a Wien filter. However, the lifetime of filaments sustains from several minutes to hours before fracture occurred while the RF one can work stably with no maintenance, and the experiment results will be given on O- ion production with two different technologies using our ion source test facility.

Morphine alleviates myocardial ischemia/reperfusion injury in rats by inhibiting TLR4/NF-κB signaling pathway.

OBJECTIVE: The aim of this study was to investigate the effect of morphine on myocardial ischemia/reperfusion (I/R) injury in rats and its underlying mechanism, thereby providing a reference for the prevention and treatment of myocardial I/R injury in clinical practice. MATERIALS AND METHODS: A total of 60 male Sprague-Dawley (SD) rats were randomly divided into 3 groups, including: Sham group (n=20), I/R group (n=20) and I/R + morphine group (n=20) using a random number table. The left anterior descending coronary artery (LAD) of rat was ligated and re-canalized, and the I/R model was established in rats. Rats in I/R + sevoflurane (SEV) group were pretreated with 2.5% SEV. Infarction area of heart in each group was detected using triphenyltetrazolium chloride (TTC) test. Ejection fraction % (EF%) and fraction shortening % (FS%) were determined by echocardiography. Hematoxylin-eosin (HE) staining assay was performed to detect the morphological changes of cardiac myocardial cells in each group. Meanwhile, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) staining was adopted to detect the apoptosis of myocardial cells and fibroblasts. In addition, the expression levels of toll-like receptor 4 (TLR4) and p65 in heart samples of rats in each group were measured via immuno-histochemical staining. Finally, the influence of morphine on TLR4/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway was detected using Western blotting. RESULTS: Morphine significantly alleviated I/R-induced cardiac dysfunction in rats, whereas significantly increased EF% and FS% (p<0.05). In addition, morphine evidently inhibited myocardial infarction caused by I/R injury. Meanwhile, it reduced the infarction area from [(59.61±3.41) %] to [(26.67±3.62) %] (p<0.05). The results of HE staining showed that compared with I/R group, I/R + morphine group exhibited remarkably tidier cardiac myofilament, less degradation and necrosis, as well as significantly relieved cellular edema. Immuno-histochemical staining results revealed that morphine overtly reversed decreased expressions of TLR4 and p65 induced by I/R in rats (p<0.05). Furthermore, Western blotting found that morphine significantly inhibited the protein expressions of TLR4 and phosphorylated p65. CONCLUSIONS: Morphine clearly alleviates I/R-induced myocardial injury in rats. The possible mechanism may be associated with the inhibition on TLR4/NF-κB signaling pathway.