Lonicerin promotes wound healing in diabetic rats by enhancing blood vessel regeneration through Sirt1-mediated autophagy.

Among the numerous complications of diabetes mellitus, diabetic wounds seriously affect patients' quality of life and result in considerable psychological distress. Promoting blood vessel regeneration in wounds is a crucial step in wound healing. Lonicerin (LCR), a bioactive compound found in plants of the Lonicera japonica species and other honeysuckle plants, exhibits anti-inflammatory and antioxidant activities, and it recently has been found to alleviate ulcerative colitis by enhancing autophagy. In this study we investigated the efficacy of LCR in treatment of diabetic wounds and the underlying mechanisms. By comparing the single-cell transcriptomic data from healing and non-healing states in diabetic foot ulcers (DFU) of 5 patients, we found that autophagy and SIRT signaling activation played a crucial role in mitigating inflammation and oxidative stress, and promoting cell survival in wound healing processes. In TBHP-treated human umbilical vein endothelial cells (HUVECs), we showed that LCR alleviated cell apoptosis, and enhanced the cell viability, migration and angiogenesis. Furthermore, we demonstrated that LCR treatment dose-dependently promoted autophagy in TBHP-treated HUVECs by upregulating Sirt1 expression, and exerted its anti-apoptotic effect through the Sirt1-autophagy axis. Knockdown of Sirt1 significantly decreased the level of autophagy, and mitigated the anti-apoptotic effect of LCR. In a STZ-induced diabetic rat model, administration of LCR significantly promoted wound healing, which was significantly attenuated by Sirt1 knockdown. This study highlights the potential of LCR as a therapeutic agent for the treatment of diabetic wounds and provides insights into the molecular mechanisms underlying its effects.

Progenitor cell diversity in the developing mouse neocortex.

In the mammalian neocortex, projection neuron types are sequentially generated by the same pool of neural progenitors. How neuron type specification is related to developmental timing remains unclear. To determine whether temporal gene expression in neural progenitors correlates with neuron type specification, we performed single-cell RNA sequencing (scRNA-Seq) analysis of the developing mouse neocortex. We uncovered neuroepithelial cell enriched genes such as Hmga2 and Ccnd1 when compared to radial glial cells (RGCs). RGCs display dynamic gene expression over time; for instance, early RGCs express higher levels of Hes5, and late RGCs show higher expression of Pou3f2 Interestingly, intermediate progenitor cell marker gene Eomes coexpresses temporally with known neuronal identity genes at different developmental stages, though mostly in postmitotic cells. Our results delineate neural progenitor cell diversity in the developing mouse neocortex and support that neuronal identity genes are transcriptionally evident in Eomes-positive cells.

Differences in the Development of Mathematics Motivation within and across Socioeconomic Status: Do Early Adolescents' Failure Beliefs Matter?

Interest in socioeconomic differences in academic motivation has been longstanding. However, previous research has often treated both low- and high-SES students as homogenous groups. This study aims to address this gap by investigating the developmental trajectory profiles of mathematics motivation during early adolescence, with a focus on variations within and across SES groups. Multigroup latent class growth analysis was used on a sample of 3718 early adolescents in China (initial Mage was 9.40 ± 0.52 years; 48.0% girls) across 2 years from grades 4 through 6. The analysis identified three distinct self-determined mathematics motivation trajectory profiles within each SES group: a good-quality profile (i.e., initially high autonomous but low controlled), a high-quantity profile (i.e., initially high both autonomous and controlled), and a low-quantity profile (i.e., initially low both autonomous and controlled). A greater proportion of low-SES students were observed within the low-quantity profile than within the good-quality profile. The study found that the failure-is-enhancing view was a protective factor against two relatively maladaptive motivational trajectory profiles (i.e., high-quantity profile and low-quantity profile), irrespective of socioeconomic background. These findings emphasize the importance of implementing motivational interventions for early adolescents that consider both structural factors (e.g., socioeconomic backgrounds) and psychological factors (e.g., failure beliefs), to foster students' academic development.

[Noise exposure-induced stress response and its measurement methods].

Noise, as an unavoidable stress (pressure) source in the modern life, affects animals in many ways, both behaviorally and physiologically. Behavioral changes may be driven by changes in hormone secretion in animals. When animals face with noise stress, the neuroendocrine systems, mainly the hypothalamic-pituitary-adrenal (HPA) axis, are activated, which promotes the secretion and release of stress hormones, and then leads to a series of behavioral changes. The behavioral changes can be easily observed, but the changes in physiological indicators such as hormone levels need to be accurately measured. Currently, many studies have measured the variations of stress hormone levels in animals under different noise conditions. Taking glucocorticoid as an example, this paper summarizes the different measurement methods of stress hormones, especially the non-invasive measurement methods, and compares the advantages and shortcomings of them. It provides a variety of measurement choices for the study of related issues, and also helps us to further understand the sources of animal stress, in order to provide a better habitat for animals.

Variants in ADD1 cause intellectual disability, corpus callosum dysgenesis, and ventriculomegaly in humans.

PURPOSE: Adducins interconnect spectrin and actin filaments to form polygonal scaffolds beneath the cell membranes and form ring-like structures in neuronal axons. Adducins regulate mouse neural development, but their function in the human brain is unknown. METHODS: We used exome sequencing to uncover ADD1 variants associated with intellectual disability (ID) and brain malformations. We studied ADD1 splice isoforms in mouse and human neocortex development with RNA sequencing, super resolution imaging, and immunoblotting. We investigated 4 variant ADD1 proteins and heterozygous ADD1 cells for protein expression and ADD1-ADD2 dimerization. We studied Add1 functions in vivo using Add1 knockout mice. RESULTS: We uncovered loss-of-function ADD1 variants in 4 unrelated individuals affected by ID and/or structural brain defects. Three additional de novo copy number variations covering the ADD1 locus were associated with ID and brain malformations. ADD1 is highly expressed in the neocortex and the corpus callosum, whereas ADD1 splice isoforms are dynamically expressed between cortical progenitors and postmitotic neurons. Human variants impair ADD1 protein expression and/or dimerization with ADD2. Add1 knockout mice recapitulate corpus callosum dysgenesis and ventriculomegaly phenotypes. CONCLUSION: Our human and mouse genetics results indicate that pathogenic ADD1 variants cause corpus callosum dysgenesis, ventriculomegaly, and/or ID.

Molecular characterization, expression, and function of Vitellogenin genes in Phytoseiulus persimilis.

Vitellogenin (Vg) is an important factor that impacts oocyte maturation, egg formation and embryonic development in Arthropoda. Two orthologs of Vg gene were obtained from the genome of Phytoseiulus persimilis and termed as PpVg1 and PpVg2. Both orthologs belong to the large lipid transfer protein superfamily. The expression of PpVg1 and PpVg2 was low in immatures and male adults, and increased rapidly in female adults after mating, and reached a peak before the first egg was laid (168×  and 20.5×  the level in virgin females, respectively). When PpVg1 and PpVg2 were interfered with dsRNA, the relative expression decreased by 81.0 and 30.9%, respectively, and 7.8 and 31.4% interfered individuals died within 24 h. Among surviving individuals, ca. 51.1 and 44.8% are infertile. Factors that might be related to expression of Vg genes are also discussed.

[Research progress of the regulation of cochlear sensitivity to noise by circadian rhythm].

High level noise can damage cochlear hair cells, auditory nerve and synaptic connections between cochlear hair cells and auditory nerve, resulting in noise-induced hearing loss (NIHL). Recent studies have shown that animal cochleae have circadian rhythm, which makes them different in sensitivity to noise throughout the day. Cochlear circadian rhythm has a certain relationship with brain-derived neurotrophic factor and glucocorticoids, which affects the degree of hearing loss after exposure to noise. In this review, we summarize the research progress of the regulation of cochlear sensitivity to noise by circadian rhythm and prospect the future research direction.

Tissue-specific splicing of a ubiquitously expressed transcription factor is essential for muscle differentiation.

Alternate splicing contributes extensively to cellular complexity by generating protein isoforms with divergent functions. However, the role of alternate isoforms in development remains poorly understood. Mef2 transcription factors are essential transducers of cell signaling that modulate differentiation of many cell types. Among Mef2 family members, Mef2D is unique, as it undergoes tissue-specific splicing to generate a muscle-specific isoform. Since the ubiquitously expressed (Mef2Dα1) and muscle-specific (Mef2Dα2) isoforms of Mef2D are both expressed in muscle, we examined the relative contribution of each Mef2D isoform to differentiation. Using both in vitro and in vivo models, we demonstrate that Mef2D isoforms act antagonistically to modulate differentiation. While chromatin immunoprecipitation (ChIP) sequencing analysis shows that the Mef2D isoforms bind an overlapping set of genes, only Mef2Dα2 activates late muscle transcription. Mechanistically, the differential ability of Mef2D isoforms to activate transcription depends on their susceptibility to phosphorylation by protein kinase A (PKA). Phosphorylation of Mef2Dα1 by PKA provokes its association with corepressors. Conversely, exon switching allows Mef2Dα2 to escape this inhibitory phosphorylation, permitting recruitment of Ash2L for transactivation of muscle genes. Thus, our results reveal a novel mechanism in which a tissue-specific alternate splicing event has evolved that permits a ubiquitously expressed transcription factor to escape inhibitory signaling for temporal regulation of gene expression.

Notch1 protects against myocardial ischaemia-reperfusion injury via regulating mitochondrial fusion and function.

Mitochondrial fusion and fission dynamic are critical to the myocardial protection against ischaemia-reperfusion injury. Notch1 signalling plays an important role in heart development, maturation and repair. However, the role of Notch1 in the myocardial mitochondrial fusion and fission dynamic remains elusive. Here, we isolated myocardial cells from rats and established myocardial ischaemia-reperfusion injury (IRI) model. We modulated Notch1, MFN1 and DRP1 expression levels in myocardial cells via infection with recombinant adenoviruses. The results showed that Notch1 improves the cell viability and mitochondrial fusion in myocardiocytes exposed to IRI. These improvements were dependent on the regulation of MFN1 and DRP1. On the mechanism, we found that MNF1 is transcriptionally activated by RBP-Jk in myocardiocytes. Notch1 also improves the mitochondrial membrane potential in myocardiocytes exposed to IRI. Moreover, we further confirmed the protection of the Notch1-MFN1/Drp1 axis on the post-ischaemic recovery of myocardial performance is associated with the preservation of the mitochondrial structure. In conclusion, this study presented a detailed mechanism by which Notch1 signalling improves mitochondrial fusion during myocardial protection.

Inhibition of the Notch1 pathway induces peripartum cardiomyopathy.

Increased expression and activity of cardiac and circulating cathepsin D and soluble fms-like tyrosine kinase-1 (sFlt-1) have been demonstrated to induce and promote peripartum cardiomyopathy (PPCM) via promoting cleavage of 23-kD prolactin (PRL) to 16-kD PRL and neutralizing vascular endothelial growth factor (VEGF), respectively. We hypothesized that activation of Hes1 is proposed to suppress cathepsin D via activating Stat3, leading to alleviated development of PPCM. In the present study, we aimed to investigate the role of Notch1/Hes1 pathway in PPCM. Pregnant mice between prenatal 3 days and postpartum 3 weeks were fed with LY-411575 (a notch inhibitor, 10 mg/kg/d). Ventricular function and pathology were evaluated by echocardiography and histological analysis. Western blotting analysis was used to examine the expression at the protein level. The results found that inhibition of Notch1 significantly promoted postpartum ventricular dilatation, myocardial hypertrophy and myocardial interstitial fibrosis and suppressed myocardial angiogenesis. Western blotting analysis showed that inhibition of Notch1 markedly increased cathepsin D and sFlt-1, reduced Hes1, phosphorylated Stat3 (p-Stat3), VEGFA and PDGFB, and promoted cleavage of 23k-D PRL to 16-kD PRL. Collectively, inhibition of Notch1/Hes1 pathway induced and promoted PPCM via increasing the expressions of cathepsin D and sFlt-1. Notch1/Hes1 was a promising target for prevention and therapeutic regimen of PPCM.

Notch1-Nrf2 signaling crosstalk provides myocardial protection by reducing ROS formation.

Both the Notch1 and Keap1-Nrf2 signaling pathways have cardioprotective effects, but the role of Notch1-Nrf2 crosstalk in myocardial ischemia-reperfusion injury is unclear. In this study, we established hypoxia-reoxygenation in neonate rat myocardial cells and employed γ-secretase inhibitor and curcumin to inhibit and activate the Notch1 and Keap1-Nrf2 signaling pathways, respectively. We found that the combined action of the Notch1 and Keap1-Nrf2 signaling pathways significantly increased cardiomyocyte viability, inhibited cardiomyocyte apoptosis, reduced the formation of reactive oxygen species, and increased antioxidant activities. In conclusion, these findings suggest that Notch1-Nrf2 crosstalk exerts myocardial protection by reducing the formation of reactive oxygen species.

MiR-421 inhibition protects H9c2 cells against hypoxia/reoxygenation-induced oxidative stress and apoptosis by targeting Sirt3.

BACKGROUND: MicroRNAs (miRNAs) are involved in myocardial ischemia-reperfusion injury. miRNA-421 (miR-421) plays a significant role in the initiation of apoptosis and myocardial infarction. However, the molecular regulation of miR-421 in myocardial ischemia-reperfusion injury requires further elucidation. METHODS: An in vitro hypoxia/reoxygenation model was established, and the expression levels of miR-421 and Sirtuin-3 (Sirt3) in H9c2 cells were quantified using quantitative real-time polymerase chain reaction. Flow cytometry was employed to measure the effects of miR-421 on myocardial apoptosis induced by hypoxia/reoxygenation. The activity of lactate dehydrogenase and superoxide dismutase and levels of malondialdehyde were measured. The binding sites of miR-421 on Sirt3 were predicted using TargetScan software. A luciferase reporter assay was used to validate the direct targeting of Sirt3 with miR-421. Protein expression levels of Sirt3 and its downstream proteins were evaluated using Western blot analysis. RESULTS: Exposure of H9c2 cells to hypoxia/reoxygenation led to increased apoptosis, levels of malondialdehyde and lactate dehydrogenase, and decreased levels of superoxide dismutase. miR-421 knockdown resulted in decreased apoptosis, levels of lactate dehydrogenase and malondialdehyde, and increased superoxide dismutase levels in H9c2 cells. Hypoxia/reoxygenation significantly decreased the relative expression levels of Sirt3. Down-regulation of Sirt3 resulted from overexpression of miR-421, which directly targeted Sirt3. Knockdown of miR-421 up-regulated Sirt3 expression, inhibited activation of the Jun N-terminal kinase/activator protein 1 pathway and caspase 9/3-dependent cell death. CONCLUSION: The miR-421-Sirt3-Jun N-terminal kinase/activator protein 1 axis is a novel molecular mechanism that accommodates hypoxia/reoxygenation-induced oxidative stress and apoptosis and provides a new direction for the study and treatment of hypoxia/reoxygenation.

NSD2 promotes ventricular remodelling mediated by the regulation of H3K36me2.

Histone lysine methylation plays an important role in the regulation of ventricular remodelling. NSD2 is involved in many types of tumours through enhancing H3K36me2 expression. However, the role of NSD2 in the regulation of histone lysine methylation during ventricular remodelling remains unclear. In this study, we established cardiac hypertrophy model in C57BL/6 mice by transverse aortic constriction and found that histone lysine methylation participated in ventricular remodelling regulation via the up-regulation of H3K27me2 and H3K36me2 expression. In addition, we constructed transgenic C57BL/6 mice with conditional knockout of NSD2 (NSD2-/- ) in the myocardium. NSD2-/- C57BL/6 mice had milder ventricular remodelling and significantly improved cardiac function compared with wild-type mice, and the expression of H3K36me2 but not H3K27me2 was down-regulated. In conclusion, NSD2 promotes ventricular remodelling mediated by the regulation of H3K36me2.

Notch signaling inhibits cardiac fibroblast to myofibroblast transformation by antagonizing TGF-ß1/Smad3 signaling.

PURPOSE: During myocardial infarction (MI), cardiac fibroblasts (CFs) transform into myofibroblast (CMT). This study aimed to investigate the crosstalk of Notch1 and transforming growth factor-ß1 (TGF-ß1)/Smad3 signaling in the regulation of CMT and myocardial fibrosis. METHODS: Primary CFs were isolated from young rats and treated with TGF-ß1 or adenovirus to overexpress or knockdown Notch1 intracellular domain (N1ICD) or Smad3. RESULTS: TGF-ß1 decreased the expression of fibroblast markers but increased the expression of myofibroblast markers in rat CFs. TGF-ß1 increased the proliferation, invasion, and adhesion, and the secretion of collagen I of CFs, and these effects were inhibited by N1ICD overexpression. Moreover, endogenous Smad3 phosphorylation in CFs was enhanced by N1ICD knockdown, whereas TGF-ß1 induced Smad3 phosphorylation was antagonized by the N1ICD overexpression. Conversely, endogenous N1ICD activation in CFs was antagonized by Smad3, whereas TGF-ß1 induced N1ICD inactivation was antagonized by Smad3 knockdown. Coimmunoprecipitation showed that N1ICD interacted with Smad3 and immunostaining revealed the colocalization of N1ICD and Smad3 in the nuclei of CFs. Moreover, we demonstrated the functional antagonism of N1ICD and Smad3 on the phenotypes of CFs. Finally, TGF-ß1/Smad3 signaling promoted whereas Notch signaling inhibited myocardial fibrosis in rat MI model. CONCLUSION: Notch signaling inhibits CMT by antagonizing TGF-ß1/Smad3 signaling. Notch signaling activators and TGF-ß1/Smad3 signaling inhibitors could be exploited for therapeutic intervention to inhibit myocardial fibrosis after MI.

Notch1 provides myocardial protection by improving mitochondrial quality control.

Mitochondrial quality control is a new target for myocardial protection. Notch signaling plays an important role in heart development, maturation, and repair. However, the role of Notch in the myocardial mitochondrial quality control remains elusive. In this study, we isolated myocardial cells from rats and established myocardial ischemia reperfusion injury (IRI) model. We modulated Notch1 expression level in myocardial cells via infection with recombinant adenoviruses Ad-N1ICD and Ad-shN1ICD. We found that IR reduced myocardial cells viability, but Notch1 overexpression increased the viability of myocardial cells exposed to IRI. In addition, Notch1 overexpression improved ATP production, increased mitochondrial fusion and decreased mitochondrial fission, and inhibited mitophagy in myocardial cells exposed to IRI. However, N1ICD knockdown led to opposite effects. The myocardial protection role of Notch1 was related to the inhibition of Pink1 expression and Mfn2 and Parkin phosphorylation. In conclusion, Notch1 exerts myocardial protection and this is correlated with the maintenance of mitochondrial quality control and the inhibition of Pink1/Mfn2/Parkin signaling.

Nanoparticles-Enabled Surface-Enhanced Imaging Ellipsometry for Amplified Biosensing.

The main issues of imaging ellipsometry-based biosensing for small molecules are the low sensitivity and narrow detection range due to the low molecular weight of small molecules that results in a negligible signal. To meet this challenge, we theoretically investigated the deciding factors of the ellipsometry signal and further applied the theory to guide the design of ellipsometry-based biosensor using metal nanoparticles that have a high dielectric constant. Significant signal amplification effects can be achieved by using nanoparticle labels including magnetic nanoparticles and gold nanoparticles. Guided by the theory, we have developed a sensitive surface-enhanced imaging ellipsometry (SEIE)-biosensor for detecting chloramphenicol in real milk sample with high sensitivity (with a limit of detection of 6 pg/mL) and broaden detection range. This nanoparticles-enabled SEIE not only greatly improves the sensitivity of conventional imaging ellipsometry-based biosensors but also retains the advantages of conventional methods in terms of automated and convenient operation, providing an effective strategy for detection of trace small molecules in complex samples that holds great promise in scientific research, clinical diagnosis, and food safety.

NSD2 silencing alleviates pulmonary arterial hypertension by inhibiting trehalose metabolism and autophagy.

Nuclear receptor binding SET domain 2 (NSD2)-mediated metabolic reprogramming has been demonstrated to regulate oncogenesis via catalyzing the methylation of histones. The present study aimed to investigate the role of NSD2-mediated metabolic abnormality in pulmonary arterial hypertension (PAH). Monocrotaline (MCT)-induced PAH rat model was established and infected with adeno-associated virus carrying short hairpin RNA (shRNA) targeting NSD2. Hemodynamic parameters, ventricular function, and pathology were evaluated by microcatheter, echocardiography, and histological analysis. Metabolomics changes in lung tissue were analyzed by LC-MS. The results showed that silencing of NSD2 effectively ameliorated MCT-induced PAH and right ventricle dysfunction, and partially reversed pathological remodeling of pulmonary artery and right ventricular hypertrophy. In addition, the silencing of NSD2 markedly reduced the di-methylation level of H3K36 (H3K36me2 level) and inhibited autophagy in pulmonary artery. Non-targeted LC-MS based metabolomics analysis indicated that trehalose showed the most significant change in lung tissue. NSD2-regulated trehalose mainly affected ABC transporters, mineral absorption, protein digestion and absorption, metabolic pathways, and aminoacyl-tRNA biosynthesis. In conclusion, we reveal a new role of NSD2 in the pathogenesis of PAH related to the regulation of trehalose metabolism and autophagy via increasing the H3K36me2 level. NSD2 is a promising target for PAH therapy.

Fluorescence "Off-On" Probe for L-Cysteine Detection Based on Nitrogen Doped Carbon Dots.

Herein, a simple and efficient fluorescence analysis method for L-Cysteine (L-Cys) was established. The method was based on the fluorescent "off-on" mode of nitrogen doped carbon dots (NCDs). The NCDs were prepared via a facile one-step solvothermal method. In the process of exploring the bio-functional application of these newly synthesized NCDs, we found these NCDs with rich functional groups exhibited excellent optical properties. In addition, these newly synthesized NCDs showed an excitation-dependent emissions photolumine-scent (PL) property and exhibited good performance in the detection of Fe3+ ions by quenching the blue emission fluorescence. Interestingly, the quenched fluorescence of NCDs was recovered with the addition of L-Cys, which provided a novel approach for L-Cys detection. The NCDs-based fluorescent "off-on" sensor has a wide linear detection range (0-100 µM), and a relatively low detection limits (0.35 µM) for L-Cys. This simple fluorescent "off-on" approach is, very sensitive and selective for L-Cys detection, which also provides a new insight on NCDs biosensor application.

miR-21 promotes cardiac fibroblast-to-myofibroblast transformation and myocardial fibrosis by targeting Jagged1.

Myocardial fibrosis after myocardial infarction (MI) is a leading cause of heart diseases. MI activates cardiac fibroblasts (CFs) and promotes CF to myofibroblast transformation (CMT). This study aimed to investigate the role of miR-21 in the regulation of CMT and myocardial fibrosis. Primary rat CFs were isolated from young SD rats and treated with TGF-ß1, miR-21 sponge or Jagged1 siRNA. Cell proliferation, invasion and adhesion were detected. MI model was established in male SD rats using LAD ligation method and infected with recombinant adenovirus. The heart function and morphology was evaluated by ultrasonic and histological analysis. We found that TGF-ß1 induced the up-regulation of miR-21 and down-regulation of Jagged1 in rat CFs. Luciferase assay showed that miR-21 targeted 3'-UTR of Jagged1 in rat CFs. miR-21 sponge inhibited the transformation of rat CFs into myofibroblasts, and abolished the inhibition of Jagged1 mRNA and protein expression by TGF-ß1. Furthermore, these effects of miR-21 sponge on rat CFS were reversed by siRNA mediated knockdown of Jagged1. In vivo, heart dysfunction and myocardial fibrosis in MI model rats were partly improved by miR-21 sponge but were aggravated by Jagged1 knockdown. Taken together, these results suggest that miR-21 promotes cardiac fibroblast-to-myofibroblast transformation and myocardial fibrosis by targeting Jagged1. miR-21 and Jagged1 are potential therapeutic targets for myocardial fibrosis.

Notch signaling promotes angiogenesis and improves cardiac function after myocardial infarction.

Currently, the role of Notch signaling during myocardial infarction (MI) remains controversy. In this study we used in vitro and in vivo approaches to investigate the role of Notch signaling in MI. Using cultured human umbilical vein endothelial cells exposed to hypoxia/reoxygenation (H/R), we demonstrated that H/R inhibited the proliferation, VEGF secretion, and tube formation of HUVECs, and these effects were correlated with the inhibition of Notch signaling. Furthermore, these effects were antagonized by overexpression of NICD but aggravated by knockdown of NICD. In addition, in MI model rats we found that heart dysfunction and angiogenesis in model rats was partly improved by NICD overexpression but was aggravated by knockdown of NICD. In conclusion, these data demonstrate that Notch signaling is downregulated in H/R injury in the hearts. Artificial activation of Notch signaling could promote myocardial survival and angiogenesis and improve cardiac function following H/R injury.