Follicular fluid exosome-derived miR-339-5p enhances in vitro maturation of porcine oocytes via targeting SFPQ, a regulator of the ERK1/2 pathway.

In this study, we aimed to investigate cytoplasmic maturation and miRNA expression of mature oocytes cultured in porcine follicular fluid exosomes. We also examined the effect of miR-339-5p on oocyte maturation. Twenty eight differentially expressed miRNAs were detected using miRNA-seq. We then transfected cumulus oocyte complexes with miR-339-5p mimics and inhibitor during culture. The results showed that exosomes increased endoplasmic reticulum levels and the amount of lipid droplets, and decreased ROS levels, lipid droplet size, and percentage of oocytes with abnormal cortical granule distribution. Overexpressing miR-339-5p significantly decreased cumulus expansion genes, oocyte maturation-related genes, target gene proline/glutamine-rich splicing factor (SFPQ), ERK1/2 phosphorylation levels, oocyte maturation rate, blastocyst rate, and lipid droplet number, but increased lipid droplet size and the ratio of oocytes with abnormal cortical granule distribution. Inhibiting miR-339-5p reversed the decrease observed during overexpression. Mitochondrial membrane potential and ROS levels did not differ significantly between groups. In summary, exosomes promote oocyte cytoplasmic maturation and miR-339-5p regulating ERK1/2 activity through SFPQ expression, thereby elevating oocyte maturation and blastocyst formation rate in vitro.

Alterations of large-scale functional network connectivity in patients with infantile esotropia before and after surgery.

BACKGROUND: Growing evidences have indicated neurodevelopmental disorders in infantile esotropia (IE). However, few studies have analyzed the characteristics of large-scale functional networks of IE patients or their postoperative network-level alterations. METHODS: Here, individuals with IE (n = 32) and healthy subjects (n = 30) accomplished the baseline clinical examinations and resting-state MRI scans. A total of 17 IE patients also underwent corrective surgeries and completed the longitudinal clinical assessments and resting-state MRI scans. Linear mixed effects models were applied for cross-sectional and longitudinal network-level analyses. Correlation analysis was performed to assess the relationship between longitudinal functional connectivity (FC) alterations and baseline clinical variables. RESULTS: In cross-sectional analyses, network-level FC were apparently aberrant in IE patients compared to controls. In longitudinal analyses, intra- and internetwork connectivity were observed with significant alterations in postoperative IE patients compared to the preoperative counterparts. Longitudinal FC changes are negatively correlated to the age at surgery in IE. CONCLUSIONS: Obviously, altered network-level FC benefiting from the corrective surgery serves as the neurobiological substrate of the observed improvement of stereovision, visuomotor coordination, and emotional management in postoperative IE patients. Corrective surgery should be performed as early as possible to obtain more benefits for IE in brain function recovery.

Effects of follicular fluid exosomes on in vitro maturation of porcine oocytes.

Exosomes are related to effective communication between cells. In this study we aimed to investigate the effect of porcine follicular fluid exosomes (FF-Exo) on cumulus expansion, oocyte mitochondrial membrane potential, and maturation in in vitro culture. We used different concentrations of FF-Exo (Exo-0, Exo-1, Exo-10, Exo-20, and Exo-40) and added them to an oocyte maturation medium. Transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blot (WB) showed that the isolated samples were exosomes. Immunofluorescence showed that exosomes could be taken up by cumulus cells. Compared with the Exo-0 group, there was no significant difference in oocyte maturation rate in the Exo-1 group (p > 0.05), while the Exo-10 group (p < 0.05), Exo-20 group (p < 0.01) and Exo-40 group (p < 0.01) significantly increased. The maturation rate of the Exo-20 and Exo-40 groups was the highest, and there was no significant difference between the two groups (p > 0.05). However, different concentrations of treatment could not effectively induce cumulus expansion and the results of JC1 showed that it had no significant effect on mitochondrial membrane potential (p > 0.05). In conclusion, the results suggest that porcine FF-Exo are involved in oocyte nuclear maturation.

Inhibition of 26S proteasome enhances AKAP3-mediated cAMP-PKA signaling during boar sperm capacitation.

This study investigates the effects of the ubiquitin-proteasome pathway (UPP) on porcine sperm capacitation and its interactions with the cAMP-PKA pathway. The semen of adult Landrace boars was divided into four groups: non-capacitated, capacitated, 10 µM/mL MG132, and 10 µM/mL DMSO groups. We characterized the parameters related to sperm dynamics using a computer-assisted sperm analysis system. The level of sperm protein tyrosine phosphorylation was detected using Western blotting, and the change of zinc ion signal was detected via flow cytometry. The relationship between A-kinase-anchor protein 3 (AKAP3), ubiquitin (Ub), and protein kinase A (PKA) was assessed by co-precipitation assays; to evaluate the interactions between the UPP and cAMP-PKA pathway, threonine, serine, and tyrosine phosphorylation were detected using Western blotting to evaluate the interaction between the UPP and cAMP-PKA pathway; Hoechst staining was used to detect the sperm-egg binding state and evaluate the effects of UPP inhibition. During capacitation, the levels of protein tyrosine, serine, and threonine phosphorylation and ubiquitination of porcine sperm increased, and sperm-egg binding was inhibited (P < 0.05). AKAP3 was degraded by UPP, and after inhibiting the 26 S proteasome, ubiquitinated AKAP3 accumulated in large quantities. Our findings indicate that, after the 26 S proteasome was inhibited, PKA was uncoupled from AKAP3 and degraded by UPP; the level of tyrosine phosphorylation induced by PKA-AKAP3 was reduced, the level of serine threonine phosphorylation increased, and the ubiquitination pathway interacted with the phosphorylation pathway and was involved in sperm capacitation.

Abnormal developmental trends of functional connectivity in young children with infantile esotropia.

Previous studies have shown that functional networks are present at birth and change dynamically throughout infancy and early childhood. However, the status of functional connectivity is still poorly understood in patients with infantile esotropia (IE). The aim of this study is to investigate the developmental trends of functional connectivity in patients with IE during a critical period of growth and development. A total of 17 patients with IE (9 males and 8 females; mean age: 3.36 ± 2.03 years, age range: 0.67-6.36 years) and 20 healthy subjects matched for age and gender were recruited and underwent resting-state functional magnetic resonance imaging. The whole-brain functional network connectivity was analyzed for the IE group and healthy control group. A general linear model was applied to assess the group-age interaction in terms of the functional connectivity. The discrepancy between the two groups in functional connectivity trajectories was also quantified across age and exhibited by the quadratic parabolic model. There were significant group-age interactions between the visual network and the default mode network, the visual network and the sensorimotor network, the limbic network and the default mode network, and within the limbic network in the functional connectivity. A U-shaped tendency across age, with an "inflection point" ranging from 3.1 to 4.0 years of age was exhibited in the difference between functional connectivity trajectories of the IE patients and normal controls. Abnormality in functional network connectivity could present in IE patients at birth, exhibiting aberrant developmental patterns over time. An abnormal functional network could reduce the ability of the cortex in visual information processing, further reactivating the subcortical visual information processing system, which is probably the pathogenesis of IE. Three to four years after birth is the critical time window for children with IE to establish normal network connections in the brain. Early surgery during this period may be helpful for affected children to have an opportunity to approach the normal development trajectory as early as possible.

MicroRNA-101 regulates oocyte maturation in vitro via targeting HAS2 in porcine cumulus cells.

RNA-seq technology can be used for the detection of miRNA transcripts in tissues and cells at specific periods and under specific treatment conditions, which can easily and effectively screen out differential transcripts. The purpose of this study was to compare miRNA expression in porcine cumulus cells before and after oocyte maturation, and to investigate the mechanism whereby cumulus cells may influence oocyte maturation. To that aim, cumulus cells surrounding GV- and MII-stage oocytes were isolated, and their differences in miRNA expression were examined using miRNA-seq. 143 differentially expressed miRNAs were identified, among which miR-101 was selected and further verified by qPCR. Moreover, miR-101 was found to target HAS2 through target gene prediction, luciferase-based co-transfection and cumulus cells transfection. Transfection of COCs with miR-101 mimics or inhibitor revealed that the miR-101 could inhibit oocyte IVM by regulating the expanding of CCSs, but had no effect on the embryo development competence. These findings demonstrated that miR-101 regulated oocyte maturation in vitro via targeting HAS2 in porcine cumulus cells.

Comparative proteomic identification of capacitated and non-capacitated sperm of Yanbian Yellow Cattle.

To investigate the proteomic differences between the capacitated and non-capacitated sperm of the Yanbian yellow cattle, semen was collected from three Yanbian yellow cattle, aged 3-5 years, pooled, and divided into capacitated and non-capacitated groups (n = 9) to be analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and liquid chromatography-mass spectrometry. Gene ontology enrichment, Kyoto Encyclopedia of Genes and Genomes pathway enrichment, and protein-protein interactions were used for bioinformatics analysis. The results showed that 598 were described as differentially expressed proteins during sperm capacitation. In the capacitated sperm, 89 proteins were up-regulated, and 509 proteins were downregulated, compared to the non-capacitated sperm. Western blot analysis confirmed that the expression of the Heat Shock 70-kDa Protein 5 (HSPA5) proteins was down-regulated. After HSPA5 inhibition, the level of tyrosine phosphorylation decreased, and the cleaved caspase 3 increased. The results showed that HSPA5 could regulate sperm capacitation and slow down apoptosis. Thus, providing a basis for studying the changes in protein expression during sperm capacitation, which can help identify the marker proteins potentially related to sperm capacitation. Hence, this study can deepen our understanding of the molecular processes involved in the sperm capacitation in Yanbian yellow cattle and provide a framework for future research.

Local structural-functional connectivity decoupling of caudate nucleus in infantile esotropia.

Abnormal brain structural and functional properties were demonstrated in patients with infantile esotropia (IE). However, few studies have investigated the interaction between structural and functional connectivity (SC-FC) in patients with IE. Structural network was generated with diffusion tensor imaging and functional network was constructed with resting-state functional magnetic resonance imaging for 18 patients with IE as well as 20 age- and gender- matched healthy subjects. The SC-FC coupling for global connectome, short connectome and long connectome were examined in IE patients and compared with those of healthy subjects. A linear mixed effects model was employed to examine the group-age interaction in terms of the coupling metrics. The Pearson correlation between coupling measures and strabismus degree was evaluated in IE patients, on which the regulatory effect of age was also investigated through hierarchical regression analysis. Significantly decreased SC-FC coupling score for short connections was observed in left caudate nucleus (CAU) in IE patients, whereas no brain regions exhibited altered coupling metrics for global connections or long connections. The group-age interaction was also evident in local coupling metrics of left CAU. The age-related regulatory effect on coupling-degree association was distinguishing between brain regions implicated in visual processing and cognition-related brain areas in IE patients. Local SC-FC decoupling in CAU was evident in patients with IE and was initiated in their early postnatal period, possibly interfering the visual cortico-striatal loop and subcortical optokinetic pathway subserving visual processing and nasalward optokinesis during neurodevelopment, which provides new insight into underlying neuropathological mechanism of IE.

Effects of partially replacing glycerol with cholesterol-loaded cyclodextrin on protamine deficiency, in vitro capacitation and fertilization ability of frozen-thawed Yanbian Yellow cattle sperm.

Glycerol is widely used as a cryoprotectant to protect the sperm from freezing damage during cryopreservation. However, glycerol at a high concentration has toxic effects on the sperm. Therefore, we explored the effects of partially replacing glycerol with cholesterol-loaded cyclodextrin (CLC) in a cryoprotectant on protamine deficiency, in vitro capacitation, and fertilization ability of freeze-thawed Yanbian Yellow cattle sperm. We used fresh semen, control (6% glycerol), and four treatment-I, II, III, and IV (3% glycerol + 0, 0.75, 1.5, and 3 mg/mL CLC, respectively)-groups. Computer-assisted semen analysis; JC-1, CMA3, and FluoZin-3-AM staining; flow cytometry; and IVF were conducted. Replacing a portion of glycerol with 1.5 mg/mL CLC significantly improved sperm motility, viability, plasma membrane integrity, acrosome integrity, and membrane lipid disorders, mitochondrial membrane potential (MMP), capacitation, and fertilization ability (P < 0.05) compared with the control. Additionally, in group I and III, the protamine deficiency were significantly lower (P < 0.05) than in the control group. It was found that 6% glycerol has a higher degree of damage to sperm DNA integrity than 3% glycerol. Overall, this study revealed that partial replacement of glycerol with CLC can be used as a novel cryoprotection method to reduce the toxicity of glycerol and improve the quality of thawed Yanbian Yellow cattle sperm.

Evaluation of ubiquitination and sumoylation of acrosin inhibitor during in vitro capacitation of porcine sperm.

The main objective of this study was to investigate the expression of acrosin inhibitor (AI), ubiquitin (Ub), and small ubiquitin-related modifier 1 (SUMO1) proteins during in vitro capacitation of pig sperm. Duroc pig sperm was divided into fresh sperm and capacitation treatment groups. Protein expression was evaluated using computer-assisted sperm analysis (CASA) systems, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), western blotting, and immunofluorescence. The results showed that the expression of AI (30 kDa) incapacitated sperm was significantly lower than that in fresh sperm (P < 0.05), and that the levels of ubiquitinated and SUMO1-ylated proteins in capacitated sperm were significantly higher than those in fresh sperm (P < 0.05). Immunofluorescence results showed that AI, Ub, and SUMO1 were located in the acrosome region of the fresh and capacitated sperm heads. After capacitation, the fluorescence intensity of AI and SUMO1 decreased, while that of Ub increased. The protein band at 30 kDa represented the AI-Ub-SUMO1 complex, indicating that this complex was involved in sperm capacitation. Furthermore, SUMO1 increased the stability of AI at 30 kDa, preventing its complete decomposition, while at 46 kDa, in the absence of SUMO1, AI is bound to ubiquitin, and was completely degraded.

Effects of the E1 activating enzyme UBA2 on porcine oocyte maturation, apoptosis, and embryonic development in vitro.

The purpose of this study was to investigate the effect of the E1 activating enzyme UBA2 on the expression of the SUMO-1 protein during in vitro maturation (IVM) of pig oocytes and embryonic development. In the 5 µg/ml UBA2 treatment group, the expression of the anti-apoptotic gene Bcl-2 and the embryo cleavage rate was significantly increased, while the proapoptotic gene Bax was significantly reduced. When 10 µg/ml UBA2 was added, the in vitro maturation rate, blastocyst rate, and SUMO-1 protein content of oocytes increased significantly (p < .05), and the expression of proapoptotic gene Caspase3 was significantly decreased (p < .05), while the viability of cumulus cells was extremely significantly reduced (p < .01). In summary, UBA2 can regulate the content of the SUMO-1 protein in mature pig oocytes in vitro, which in turn affects the maturation rate of oocytes, expression of apoptosis genes, cumulus cell viability, and the development of embryos after fertilization.

BrrICE1.1 is associated with putrescine synthesis through regulation of the arginine decarboxylase gene in freezing tolerance of turnip (Brassica rapa var. rapa).

BACKGROUND: In the agricultural areas of Qinghai-Tibet Plateau, temperature varies widely from day to night during the growing season, which makes the extreme temperature become one of the limiting factors of crop yield. Turnip (Brassica rapa var. rapa) is a traditional crop of Tibet grown in the Tibet Plateau, but its molecular and metabolic mechanisms of freezing tolerance are unclear. RESULTS: Here, based on the changes in transcriptional and metabolic levels of Tibetan turnip under freezing treatment, the expression of the arginine decarboxylase gene BrrADC2.2 exhibited an accumulative pattern in accordance with putrescine content. Moreover, we demonstrated that BrrICE1.1 (Inducer of CBF Expression 1) could directly bind to the BrrADC2.2 promoter, activating BrrADC2.2 to promote the accumulation of putrescine, which was verified by RNAi and overexpression analyses for both BrrADC2.2 and BrrICE1.1 using transgenic hair root. The function of putrescine in turnip was further analyzed by exogenous application putrescine and its inhibitor DL-α-(Difluoromethyl) arginine (DFMA) under freezing tolerance. In addition, the BrrICE1.1 was found to be involved in the ICE1-CBF pathway to increase the freezing stress of turnip. CONCLUSIONS: BrrICE1.1 could bind the promoter of BrrADC2.2 or CBFs to participate in freezing tolerance of turnip by transcriptomics and targeted metabolomics analyses. This study revealed the regulatory network of the freezing tolerance process in turnip and increased our understanding of the plateau crops response to extreme environments in Tibet.

Effects of E2 binding enzyme UBC9 on porcine oocyte maturation, apoptosis and embryo development.

SUMOylation is a dynamic post-translational modification process. However, the function of small ubiquitin-like modifiers (SUMOs) in the maturation of porcine oocytes and embryo growth is not well known. Therefore, the aim of this study was to investigate the effect of E2 binding enzyme UBC9 on the expression of SUMO-1 protein during the in vitro maturation of porcine oocytes and embryo development after in vitro fertilization. Four groups were used: 0 (Control), 5, 10 and 15 µg/ml UBC9. Western blotting, flow cytometry and RT-qPCR were used to detect the in vitro maturation of porcine oocytes, SUMO-1 content, viability and the expression of apoptotic genes. Compared to those in the control treatment, the maturation rate (p < .05) and viability (p < .01) of oocytes in the 5 µg/ml treatment group decreased significantly. SUMO-1 protein markers appeared at 59 and 71 kDa and the content of SUMO-1 protein in the 10 µg/ml treatment group decreased significantly (p < .05). In the expression of apoptosis-related genes, Bcl-2 gene expression was significantly downregulated in the 10 µg/ml treatment group (p < .05). However, Bax and Caspase-3 were significantly upregulated in the 5 µg/ml treatment group (p < .05). During embryonic development, the cleavage rate of oocytes in the 10 µg/ml treatment group was significantly reduced (p < .05), whereas blastocyst formation rate in the 5 µg/ml treatment group was significantly reduced. UBC9 regulates SUMO-1 content in mature pig oocytes in vitro, which affects oocyte maturation rate, viability, apoptotic genes expression and embryo development after fertilization.

Amide Proton Transfer-Weighted (APTw) Imaging of Intracranial Infection in Children: Initial Experience and Comparison with Gadolinium-Enhanced T1-Weighted Imaging.

PURPOSE: To evaluate the performance of amide proton transfer-weighted (APTw) imaging against the reference standard of gadolinium-enhanced T1-weighted imaging (Gd-T1w) in children with intracranial infection. MATERIALS AND METHODS: Twenty-eight pediatric patients (15 males and 13 females; age range 1-163 months) with intracranial infection were recruited in this study. 2D APTw imaging and conventional MR sequences were conducted using a 3 T MRI scanner. Kappa (κ) statistics and the McNemar test were performed to determine whether the hyperintensity on APTw was related to the enhancement on Gd-T1w. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of APTw imaging to predict lesion enhancement were calculated. RESULT: In twelve patients with brain abscesses, the enhancing rim of the abscesses on the Gd-T1w images was consistently hyperintense on the APTw images. In eight patients with viral encephalitis, three showed slight spotted gadolinium enhancement, while the APTw image also showed a slight spotted high signal. Five of these patients showed no enhancement on Gd-T1w and isointensity on the APTw image. In eleven patients with meningitis, increased APTw signal intensities were clearly visible in gadolinium-enhancing meninges. Sixty infectious lesions (71%) showed enhancement on Gd-T1w images. The sensitivity and specificity of APTw were 93.3% (56/60) and 91.7% (22/24). APTw demonstrated excellent agreement (κ = 0.83) with Gd-T1w, with no significant difference (P = 0.69) in detection of infectious lesions. CONCLUSIONS: These initial data show that APTw MRI is a noninvasive technique for the detection and characterization of intracranial infectious lesions. APTw MRI enabled similar detection of infectious lesions to Gd-T1w and may provide an injection-free means of evaluation of intracranial infection.

Uncovering the role of a positive selection site of wax ester synthase/diacylglycerol acyltransferase in two closely related Stipa species in wax ester synthesis under drought stress.

Natural selection drives local adaptations of species to biotic or abiotic environmental stresses. As a result, adaptive phenotypic divergence can evolve among related species living in different habitats. However, the genetic foundation of this divergence process remains largely unknown. Two closely related alpine grass species, Stipa capillacea and Stipa purpurea, are distributed in different rainfall regions of northern Tibet. Here, we analyzed the drought tolerance of these two closely related Stipa species, and found that S. purpurea was more resistance to drought stress than S. capillacea. To further understand the genetic diversity behind their adaptation to drought environments, a comprehensive gene repertoire was generated using PacBio isoform and Illumina RNA sequencing technologies. Bioinformatics analyses revealed that differential transcripts were mainly enriched in the wax synthetic pathway, and a threonine residue at position 239 of WSD1 was identified as having undergone positive selection in S. purpurea. Using heterologous expression in the Saccharomyces cerevisiae mutant H1246, site-directed mutagenesis studies demonstrated that a positive selection site results in changes to the wax esters profile. This difference may play an important role in S. purpurea in response to drought conditions, indicating that S. purpurea has evolved specific strategies involving its wax biosynthetic pathway as part of its long-term adaptation to the Qinghai-Tibet Plateau.

T2 mapping in the quantitative evaluation of articular cartilage changes in children with hemophilia: A pilot study.

IMPORTANCE: Joint disease affects more than 90% of severe hemophiliacs. Early diagnosis is critical in preventing hemophilic arthritis. Magnetic resonance imaging (MRI) enables visualization of early arthropathic changes and plays an important role in treatment. OBJECTIVE: To evaluate the role of T2 mapping in detecting early cartilage lesions in the knee and ankle joints of children with hemophilic arthropathy. METHODS: Target joints of 15 male patients with clinically confirmed moderate or severe hemophilia were evaluated with MRI. In addition to routine MRI protocols (T1WI, T2_FFE, T2_SPAIR, PDW_TSE), T2 mapping was used to evaluate the articular cartilage of target joints. RESULTS: The mean T2 value of the distal femoral cartilage was 46.72 ± 10.94 ms, which is higher than the reported age-matched normal value (40.27 ± 3.50 ms). The mean T2 value of the proximal tibial cartilage was 45.60 ± 8.82 ms, which is higher than the reported normal value (31.15 ± 1.86 ms). Four examined joints (two ankles, two knees) showed normal morphology with no abnormal signal on routine MR sequences. However, T2 mapping showed locally increased T2 values in the cartilage, along with uneven color scales. INTERPRETATION: The quantitative assessment method of T2 mapping might be helpful to early diagnosis for articular cartilage lesions. It might be a potential tool for early assessment of cartilage changes and quantification of lesion's severity for hemophilia joint.

The protective effect of Egr-1 antisense oligodeoxyribonucleotide on myocardial injury induced by ischemia-reperfusion and hypoxia-reoxygenation.

AIMS: Our previous studies have shown that myocardial ischemia-reperfusion (I/R) injury is related closely with early growth response (Egr)-1 overexpression. The present study is to confirm thoroughly the effects of Egr-1 on the occurrance and development of myocardial I/R injury. METHODS: The Sprague-Dawley rat myocardial I/R model and cultured cardiomyocyte hypoxia-reoxygenation (H/R) model were established. The synthesized Egr-1 antisense oligodeoxyribonucleotide (AS-ODN) was transfected into myocardial tissues and cells. Hemodynamic parameters, myeloperoxidase (MPO), cardiac troponin I (cTnI), tumor necrosis factor-alpha (TNF-alpha), morphology, spontaneous beat and cell viability were measured to assess the degree of injury and inflammation of myocardial tissues and cells. RESULTS: In vivo, Egr-1 AS-ODN significantly attenuated injury and inflammation of myocardial tissues caused by I/R evidenced by the amelioration of hemodynamics and the reduction in MPO activity. In vitro, Egr-1 AS-ODN significantly relieved injury and inflammation of cultured cardiomyocyte caused by H/R evidenced by the improvement in morphology, structure and beat as well as the decrease in leakage of cTnI and release of TNF-alpha from cultured cardiomyocyte. CONCLUSIONS: These data suggest that Egr-1 plays a vital role in the pathogenesis of myocardial I/R injury and Egr-1 AS-ODN could protect the myocardium from I/R injury.

The protective effects of N-n-butyl haloperidol iodide on myocardial ischemia-reperfusion injury in rats by inhibiting Egr-1 overexpression.

AIMS: Our previous studies have shown that N-n-butyl haloperidol iodide (F(2)) can antagonize myocardial ischemia/reperfusion (I/R) injury by blocking intracellular Ca(2+) overload. The present study is to test the hypothesis that the protective effects of F(2) on myocardial I/R injury is mediated by downregulating Egr-1 expression. METHODS: The Sprague-Dawley rat myocardial I/R model and cardiomyocyte hypoxia/reoxygenation (H/R) model were established. With antisense Egr-1 oligodeoxyribonucleotide (ODN), the relationship between Egr-1 expression and myocardial I/R injury was investigated. Hemodynamic parameters, myeloperoxidase (MPO), cardiac troponin I (cTnI) and tumor necrosis factor-alpha (TNF-alpha) were measured to assess the degree of injury and inflammation of myocardial tissues and cells. Egr-1 mRNA and protein expressions were examined by Northern-blot and Western-blot analyses. RESULTS: Treatment with antisense Egr-1 ODN significantly reduced Egr-1 protein expression and attenuated injury of myocardial tissues and cells. Meanwhile, treatment with F(2) significantly inhibited the overexpression of Egr-1 mRNA and protein in myocardial tissues and cells. Consistent with downregulation of Egr-1 expression by F(2), inflammation and other damages were significantly relieved evidenced by the amelioration of hemodynamics, the reduction in myocardial MPO activity as well as the decrease in leakage of cTnI and release of TNF-alpha from cardiomyocyte. CONCLUSIONS: These results suggested that the overexpression of Egr-1 was causative in myocardial I/R or H/R injury, and F(2) could protect myocardial tissues and cells from I/R or H/R injury, which was largely due to the inhibition of Egr-1 overexpression.