Molecular identification of the genus Thryssa based on DNA barcoding

DNA barcoding is an effective method for identifying species by analyzing one or a few short standardized DNA sequences. In this study, we examined the utility of mitochondrial cytochrome oxidase subunit I (COI) sequences as a DNA barcode for the identification of six species belonging to the genus Thryssa: T. dussumieri, T. hamiltonii, T. kammalensis, T. mystax, T. setirostris, and T. vitrirostris. We obtained an intraspecific distance of 0.000 for T. vitrirostris and T. hamiltonii, 0.006 for T. mystax, 0.002 for T. dussumieri, and 0.005 for T. kammalensis. The average intraspecific distance was 0.002, while the average interspecific distance was 0.137. Thus, the interspecific genetic distance was approximately 67-fold larger than the intraspecific genetic distance; the average genetic distance among species was greater than the minimum of 0.020 between species suggested elsewhere. The genetic distance between T. vitrirostris and T. mystax was 0.003. A maximum-likelihood phylogenetic tree constructed using best-fitting tree topology showed distinct clusters corresponding to the species (except for T. vitrirostris and T. mystax). The closest relationship was found between T. vitrirostris and T. mystax. These two species clustered together in the phylogenetic tree. This conclusion contradicts the evolutionary relationship based on morphological classification.

2-(3',5'-Dimethoxybenzylidene) cyclopentanone, a novel synthetic small-molecule compound, provides neuroprotective effects against ischemic stroke

2-(3',5'-Dimethoxybenzylidene) cyclopentanone (DMBC) is a novel small-molecule compound synthesized by our group. Here, we found that in rat models of permanent middle cerebral artery occlusion (pMCAO), intraperitoneal injection (ip) of DMBC at 1h after ischemia reduced infarct volume, improved neurological deficits and increased the protein levels of microtubule-associated protein 2 (MAP 2) and glial fibrillary acid protein (GFAP) in the ischemic cortex. Post-treatment of DMBC still produced neuroprotective effects even when administered at 6h after ischemia. In the oxygen-glucose deprivation (OGD)-induced astrocytes or HT22 cell injury, DMBC treatment decreased the OGD-induced lactate dehydrogenase (LDH) leakage and increased the GFAP levels in astrocytes. In addition, Annexin-V-Fluos staining analysis revealed that DMBC treatment attenuated both OGD-induced apoptosis and necrosis in astrocytes. Western blotting analysis showed DMBC treatment inhibited the ischemia or OGD-induced increases in active cathepsin B in the ischemic cortex or in astrocytes or HT22 cells. Immunofluorescence analysis demonstrated that DMBC treatment blocked the ischemia or OGD-induced release of cathepsin B from the lysosomes into the cytoplasm in the ischemic cortex or in astrocytes or HT22 cells. Taken together, our results indicate that DMBC can offer neuroprotective effects against cerebral ischemia with an extended therapeutic window and its mechanism might be associated with inhibition of the cathepsin B activation.

Dielectric constant and low-frequency infrared spectra for liquid water and ice Ih within the E3B model

Two intrinsic difficulties in modeling condensed-phase water with conventional rigid non-polarizable water models are: reproducing the static dielectric constants for liquid water and ice Ih, and generating the peak at about 200 cm(-1) in the low-frequency infrared spectrum for liquid water. The primary physical reason for these failures is believed to be the missing polarization effect in these models, and consequently various sophisticated polarizable water models have been developed. However, in this work we pursue a different strategy and propose a simple empirical scheme to include the polarization effect only on the dipole surface (without modifying a model's intermolecular interaction potential). We implement this strategy for our explicit three-body (E3B) model. Our calculated static dielectric constants and low-frequency infrared spectra are in good agreement with experiment for both liquid water and ice Ih over wide temperature ranges, albeit with one fitting parameter for each phase. The success of our modeling also suggests that thermal fluctuations about local minima and the energy differences between different proton-disordered configurations play minor roles in the static dielectric constant of ice Ih. Our analysis shows that the polarization effect is important in resolving the two difficulties mentioned above and sheds some light on the origin of several features in the low-frequency infrared spectra for liquid water and ice Ih.

Combretastatin A4-phosphate and its potential in veterinary oncology: a review

For many years, research on anticancer therapy has focussed almost exclusively on targeting cancer cells directly, to selectively kill them or restrict their growth. But limited advances in this strategy have led researchers to shift their attention to other potential targets. Active research is now on-going on targeting tumour stroma. Vascular disrupting agents (VDAs) appear a promising class of anticancer drugs that are currently under investigation as a sole or combined therapy in human cancer patients. This article will briefly touch on the history and biology of combretastatin A4-phosphate (CA4P) as a typical example of VDAs and will concentrate on the side effects that can be expected when used in veterinary patients. Particularly, the pathogenesis of these side effects and how they may be prevented and/or treated will be discussed. The purpose of this article is to illustrate the potentials of CA4P as anticancer therapy in veterinary oncology patients.

Molecular epidemiology of carbapenemase-producing Escherichia coli and the prevalence of ST131 subclone H30 in Shanghai, China

The molecular characteristics and epidemiology of carbapenemase-producing Escherichia coli (CPEC) isolates from Shanghai, China, were investigated using 21 imipenem-resistant E. coli isolates obtained from a Shanghai teaching hospital from 2011 to 2014. The presence of bla KPC, bla IMP, bla VIM, bla OXA-48, and bla NDM was assessed by polymerase chain reaction (PCR) amplification and sequencing. CPEC isolates were characterized by the Etest®, multilocus sequence typing (MLST), and pulse-field gel electrophoresis (PFGE). Plasmids carrying resistance genes were analyzed by conjugation experiments, replicon typing, plasmid MLST (pMLST), S1 nuclease PFGE (S1-PFGE), and Southern hybridization. The genetic environment of the resistance genes was determined by PCR and sequencing. Among the 21 E. coli isolates, 16 produced carbapenemases; of these, ten isolates transferred carbapenemase-encoding plasmids to recipient bacteria. Nine of the 16 isolates were clonally related, and their PFGE patterns were designated type A. ST131 was the predominant sequence type (11 isolates, 68.8 %); the H30 subclone comprised 81.8 % of the ST131 strains. In all three isolates, bla IMP-4 was located on 50-kb IncN plasmids. All but two bla KPC-2 genes were carried on IncF plasmids of various sizes. Hence, both clone-spread and horizontal transfer mediated the dissemination of carbapenemase-producing genes in the Shanghai isolates.

A coarse-grained simulation for tensile behavior of 2D Au nanocrystal superlattices

We performed a coarse-grained. molecular dynamics (MD) simulation to study the unidirectional tension of 2D superlattices of alkythiol-ligated Au nanocrystals (NCs). Consistent with available experiments, the predicted Young's modulus is in the range of 6-15 GPa, exhibiting a trend of decreasing with the increasing NCs' size and decreasing ligand length. Our simulation shows that the deformation of the superlattice experiences elastic and nonelastic stages before defect nucleation at the NC level. The larger tensile strain gives rise to slips along the most densely packed lines, making them equal to [Formula: see text] with the tensile direction before deformation, which further triggers the occurrence of cavities and cracks and finally leads to the fracture of the specimen. These results provide a clear picture for the tensile behavior of 2D superlattices from deformation to rupture.

Molecular characterization of the extended-spectrum beta-lactamase (ESBL)-producing Shigella spp. in Shanghai

Shigellosis is a public health concern in China. We tested 216 Shigella isolates collected in Shanghai in 2007 for the production of extended-spectrum beta-lactamases (ESBLs). ESBL-producing isolates were characterized using polymerase chain reaction (PCR)-based genotyping, conjugation, pulsed-field gel electrophoresis (PFGE), and DNA sequence analysis of regions adjacent to bla genes. Plasmids containing genes encoding ESBLs were analyzed using plasmid replicon typing. ESBLs were produced by 18.1 % (39/216) of Shigella isolates, and all 39 ESBL-producing strains harbored bla CTX-M genes. CTX-M-14 was the most frequent variant (69.2 %, 27/39), followed by CTX-M-15 (15.4 %, 6/39). All bla CTX-M genes were transferable by conjugation, and the insertion sequence ISEcp1 was detected upstream of all bla CTX-M genes. The CTX-M-producing Shigella isolates showed high clonal diversity. IncI1, IncFII, IncN, and IncB/O replicons were respectively detected in 23 (58.9 %), 9 (23.1 %), 1 (2.6 %), and 1 (2.6 %) of the 39 transconjugants carrying bla CTX-M. The bla CTX-M-14 genes were most frequently carried by IncI1 (n = 13, 48.1 %) or IncFII (n = 9, 33.3 %) plasmids, and the bla CTX-M-15 genes were closely associated with IncI1 (n = 5, 83.3 %). Our findings demonstrate the high prevalence of ESBL-producing Shigella in Shanghai, the importance of plasmids and ISEcp1 as carriers of bla CTX-M genes, and the close association between certain bla CTX-M genes with a specific plasmid.

Kisspeptin-10 enhanced egg production in quails associated with the increase of triglyceride synthesis in liver

Our previous results showed that kisspeptin-10 (Kp-10) injections via intraperitoneal (i.p.) once daily for three weeks notably promoted the egg laying rate in quails. In order to investigate the mechanism behind the effects of Kp-10 on enhancing the egg laying rate in birds, this study focused on the alternations of lipids synthesis in liver after Kp-10 injections. 75 female quails (22 d of age) were allocated to three groups randomly, and subjected to 0 (control, Con), 10 nmol (low dosage, L) and 100 nmol (high dosage, H) Kp-10 injections via i.p. once daily for three weeks, respectively. At d 52, quails were sacrificed and sampled for further analyses. Serum E2 concentration was increased by Kp-10 injections, and reached statistical significance in H group. Serum triglyceride (TG) concentrations were increased by 46.7% in L group and 36.8% in H group, respectively, but did not reach statistical significance, and TG contents in liver were significantly elevated by Kp-10 injections in a dose-dependent manner. Serum total cholesterol (Tch) concentrations significantly decreased in H group, while in H group the hepatic Tch content was markedly increased. The level of non-esterified fatty acid (NEFA), apolipoprotein A1 and B (apoA1 and apoB) were not altered by Kp-10 injections. The genes expression of sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthetase (FAS), apolipoprotein VLDL-II (apoVLDL-II), cholesterol 7α-hydroxylase (CYP7A1) and vitellogenin II (VTG-II) were significantly up-regulated by high but not low dosage of Kp-10 injection compared to the control group. However, the expression of SREBP-2, acetyl-CoA carboxylase (ACCα), malic enzyme (ME), stearoyl-CoA (Δ9) desaturase 1 (SCD1), apolipoprotein A1 (apoA1), fatty acid binding protein 2 (FABP2), 3-hydroxyl-3-methyl glutaryl-coenzyme A reductases (HMGCR), estrogen receptor α, β (ERα and β) mRNA were not affected by Kp-10 treatment. In line with hepatic mRNA abundance, hepatic SREBP1 protein content was significantly higher in H group. Although the mRNA expression was not altered, the content of ERα protein in liver was also significantly increased in H group. However, SREBP-2 protein content in liver was not changed by Kp-10 treatment. In conclusion, exogenous Kp-10 consecutive injections during juvenile stage significantly advanced the tempo of egg laying in quails, which was associated with the significant elevation in hepatic lipids synthesis and transport.

Effects of kisspeptin-10 on lipid metabolism in cultured chicken hepatocytes

Our previous studies showed that kisspeptin-10 (Kp-10) injected in vivo can markedly increase lipid anabolism in liver of quails. In order to investigate the direct effect of Kp-10 on lipid metabolism of hepatocytes in birds, cells were separated from embryos livers and cultured in vitro with 0, 100 and 1,000 nM Kp-10, respectively. The results showed that after 24 h treatment, cells viability was not affected by 100 nM Kp-10, but showed a mild decrease with 1,000 nM Kp-10 compared to the control cells. Based on the results of the cell viability, 100 nM dosage of Kp-10 was selected for the further study and analysis. Compared with control cells, total cholesterol (Tch) contents in 100 nM treated cells were increased by 51.23%, but did not reach statistical significance, while the level of triglyceride (TG), high density of lipoprotein-cholesterol (HDL-C) and low density of lipoprotein-cholesterol (LDL-C) were significantly increased. Real-time PCR results showed that ApoVLDL-II mRNA expression had a tendency to increase, genes including sterol regulatory element-binding protein-1 (SREBP-1), acetyl coenzyme A carboxylase α (ACCα), carnitine palmitoyltransferase 1 (CPT1), 3-hydroxyl-3-methylglutaryl-coenzyme A reductases (HMGCR) and stearyl coenzyme A dehydrogenase-1 (SCD1) mRNA in hepatocytes were significantly down-regulated by 100 nM Kp-10. However, contrary to its gene expression, SREBP-1 protein expression was significantly up-regulated by 100 nM Kp-10. Some of the significant correlations in mRNA expression were found between genes encoding hepatic factors or enzymes involved in lipid metabolism in liver of birds. These results indicate that Kp-10 stimulates lipid synthesis directly in primary cultured hepatocytes of chickens.

Differential expression of hypothalamic fear- and stress-related genes in broiler chickens showing short or long tonic immobility

The serotonin system and the hypothalamic-pituitary-adrenal axis play important roles in modulating fear and stress-coping characteristics. Tonic immobility (TI) is a fear-related phenotype, and previously we have shown that broiler chickens showing short TI (STI) duration experience better growth performance and higher adaptability to stress. Here, we sought to further elucidate the central mechanisms underlying the phenotypic differences between chickens showing STI and long TI duration, by comparing the hypothalamic expression of genes in the serotonergic system and the hypothalamic-pituitary-adrenal axis under basal and corticosterone-exposed situations. The STI broilers had significantly lower (P < 0.01) hypothalamic expression of serotonin reuptake transporter and serotonin receptor 1A. Moreover, 11β-hydroxysteroid dehydrogenase type 2 was expressed significantly lower in STI chickens at the level of both mRNA (P < 0.01) and protein (P < 0.05). Hypothalamic expression of glucocorticoid receptor (GR) mRNA tended to be higher (P < 0.059) in long TI chickens, but the protein content was approximately 2 times higher (P < 0.01) in STI chickens. The uncoupled expression of GR mRNA and protein was associated with significantly lower (P < 0.05) expression of gga-miR-181a, gga-miR-211, and gga-miR-22, which are predicted to target GR, in STI chickens. Corticosterone administration reduced the mRNA expression of postsynaptic serotonin receptors, 5-hydroxytryptamine receptor 1B (P = 0.059) and 5-hydroxytryptamine receptor 7 (P < 0.05), yet significantly increased the protein content of 11β-hydroxysteroid dehydrogenase type 2 (P < 0.05). These results suggest that broilers of different TI phenotypes have a distinct pattern of hypothalamic expression of fear- and stress-related genes.

Blood pressure-lowering effects of GLP-1 receptor agonists exenatide and liraglutide: a meta-analysis of clinical trials

AIMS

Aside from lowering blood glucose, glucagon-like peptide-1 receptor agonists (GLP-1 RAs) attract much attention because of their cardioprotective effects. The aim of this study was to assess the blood pressure-lowering effects of the GLP-1 RAs exenatide and liraglutide compared with other common drugs used to treat type 2 diabetes (T2DM) based on randomized controlled trials (RCTs) including data describing complete blood pressure (BP) changes from baseline.

METHODS

We searched the major databases for published or unpublished RCTs that had been performed in patients with T2DM and compared the effects of exenatide and liraglutide to those of other common drugs used to treat T2DM. The RCTs that included data describing BP changes between the baseline and the end of the study were selected for further analysis.

RESULTS

A total of 16 RCTs that enrolled 3443 patients in the GLP-1 RA treatment group and 2417 subjects in the control group were included in this meta-analysis. The GLP-1 RA exenatide reduced systolic blood pressure (SBP) when compared with both placebo and insulin glargine, with mean differences of -5.24 and -3.46 mmHg, respectively, and with 95% confidence intervals (CI) of -6.88 to -3.59, p < 0.00001 and -3.63 to -3.29, p < 0.00001, respectively. Meanwhile, in the exenatide-treated group, diastolic blood pressure (DBP) was reduced by -5.91 mmHg, with a 95% CI of -7.53 to -4.28, p < 0.00001 compared with the placebo group, and -0.99 mmHg with a 95% CI of -1.12 to -0.87, p < 0.00001 compared with the sitagliptin group. SBP changes in this meta-analysis were assessed in the groups treated with 1.2 or 1.8 mg liraglutide per day. In the 1.2 mg-treated group, liraglutide treatment reduced SBP compared with placebo and glimepiride treatment, with mean differences of -5.60 and -2.38 mmHg, and 95% CIs of -5.84 to -5.36, p < 0.00001 and -4.75 to -0.01, p = 0.05, respectively. In the 1.8-mg-treated group, liraglutide also reduced SBP compared with placebo and glimepiride treatment with mean differences of -4.49 and -2.62 mmHg, and a 95% CI of -4.73 to -4.26, p < 0.00001, and -2.91 to -2.33, p < 0.00001, respectively.

CONCLUSION

Treatment with the GLP-1 RAs exenatide and liraglutide reduced SBP and DBP by 1 to 5 mmHg compared with some other anti-diabetic drugs including insulin, glimepiride and placebo for patients with T2DM. GLP-1 RAs may offer an alternative therapy for these patients and will help provide extra cardiovascular benefits.

Serum microRNAs as potential biomarkers of mandibular prognathism

OBJECTIVES

The aim of the study was to determine whether the expression levels of specific circulating serum microRNAs (miRNAs) are associated with mandibular prognathism (MP).

METHODS

Sixty subjects in the early permanent dentition stage and 23 in the mixed dentition stage with MP were identified. Sixty-eight normal control subjects in the early permanent dentition stage and 24 in the mixed dentition stage were recruited for comparison. According to the microarray-based expression profiling, four serum miRNAs (let-7i-3p, miR-595, miR-16-2-3p, and miR-367-5p) were validated.

RESULTS

In the MP groups, let-7i-3p was significantly over-expressed in subjects in the early permanent (P < 0.0005) and mixed (P < 0.001) dentitions, and miR-595 was significantly under-expressed (P < 0.004) in subjects in the early permanent (P < 0.004) and mixed (P < 0.0005) dentitions, compared with normal control groups. Multiple logistic regression analysis and receiver operating characteristic curve analysis revealed that let-7i-3p and miR-595 were able to significantly discriminate MP subjects from normal controls.

CONCLUSION

Let-7i-3p and miR-595 could be potential, non-invasive biomarkers for the accurate early detection and diagnosis of MP, which may result in improved clinical management.

Parity violation of electroweak force in phase transitions of single crystals of d- and L-alanine and valine

Three kinds of experiments have been designed in attempting to observe theparity violation of electroweak force at the phase transition of singlecrystals of D- and L-alanine and valine.(1) An obvious λ phasetransition at 270 ± 1 K was shown in the specific heat measurement ofalanine and valine enantiomers by differential scanning calorimetry. Thebiologically dominant L-enantiomer was found to have lower energy. (2)Magnetization of single crystals of D- and L-alanine and D-valine weremeasured as a function of temperature using the SQUID magnetometer. Thedifference of the mass susceptibility χ(ρ) ∼ T curve between theD-alanine and L-alanine is attributable to the variation of intramoleculargeometry of chirality density, which is related to the parity violationenergy shift of a chiral molecule and is a consequence of the short rangeof the weak interaction between the nuclei and electrons. (3) Laser Ramanspectra of D- and L-alanine at different low temperatures (100 K, 250 K,260 K, 270 K, 280 K and 290 K) showed that the second order Cα-Hdeformation modes at 2606 cm(-1), 2724 cm(-1) of D-alanine vanishedat 270 K but reappeared at 100 K. In the same method, L-alanine has nosuch phenomenon. An obvious decrease in the scattering intensity of themethyne group C(α)-H stretching mode at 2964 cm(-1) in D-alanineoccurs at the λ transition temperature. We present our experimentsinvolving the possible relevance of Z(0) force with Salam's putativephase transition in the origin of homochirality.

Hydrogen Bonding and OH-Stretch Spectroscopy in Water: Hexamer (Cage), Liquid Surface, Liquid, and Ice

We present a unified picture of how OH-stretch spectroscopy in water can be understood in terms of hydrogen bonding for the four systems listed in the title. To understand the strength, and hence OH-stretch frequency, of a hydrogen bond, it is crucial to consider the number of additional acceptor hydrogen bonds made by both the donor and acceptor molecules. This necessity for focusing on the hydrogen-bond environment of both donor and acceptor molecules follows from quantum chemical considerations and is related to the three-body interactions in water. Armed with this understanding we can make a detailed interpretation of the OH-stretch IR absorption spectrum of the cage conformer for HOD(D2O)5 and the imaginary part of the ssp OH-stretch sum-frequency spectrum of the surface of liquid D2O with dilute HOD.

Performance of a modified rabbit model of abdominal aortic aneurysm induced by topical application of porcine elastase: 5-month follow-up study

OBJECTIVES

To modify the method for creating an abdominal aortic aneurysm in rabbits, and to study its performance.

MATERIALS AND METHODS

A total of 24 New Zealand white rabbits were induced topically with 10 μl of porcine elastase (0, 0.1, 5 and 10 units μl(-1)) to define the optimal concentration (groups A-D). Twelve aneurysms were induced with 10 units μl(-1) of 10 μl elastase to serve as a follow-up group (group E) to serve as a follow-up. A 1.5-cm aortic segment was isolated and induced with elastase solution for 30 min.

RESULTS

All animals in groups D and E developed AAA by day 5. Aneurysms in Group E were stable over 100 days. Partial destruction to disappearance of elastic lamellae and smooth muscle cells (SMCs) was seen in elastase-treated animals by day 5. Regenerated elastin and proliferated SMCs were present in group E. Matrix metalloproteinases 2 and 9 and RAM11 showed strong expression in group D, but expression decreased in group E after day 15.

CONCLUSIONS

The rabbit AAA model induced via topical application of porcine elastase at 10 units μl(-1) for 30 min appears easy and simple, with shorter induction and more rapid aortic dilation. The model is stable over 100 days and is useful to study the formation and progress of AAAs.

Use of Cardioselective ß-Blockers in Patients with Chronic Obstructive Pulmonary Disease: A Meta-Analysis of Randomized, Placebo-controlled, Blinded Trials

Objective:

To assess the effect of cardioselective b-blockers on pulmonary function in patients with chronic obstructive pulmonary disease (COPD).

Methods:

The Embase and MEDLINE™ databases and the Cochrane Controlled Trials Register were searched comprehensively to identify all relevant clinical trials in humans published between January 1966 and May 2011. Randomized, blinded, placebo-controlled trials that studied the effects of cardioselective ß-blockers on the forced expiratory volume in 1 s (FEV1) and the responsiveness of the FEV1 to ß-agonist administration in patients with COPD were included in the analysis.

Results:

Five studies were identified: four of these assessed both cardioselective and nonselective ß-blockers; one assessed only cardioselective ß-blockers. The FEV1 was shown to decrease by 0.14 l with nonselective ß-blockers and by 0.03 l with cardioselective ß-blockers. The responsive -ness of the FEV1 to ß-agonist administration decreased significantly by 13.42% after nonselective ß-blockers, but did not change significantly after cardioselective -blocker administration.

Conclusion:

This meta-analysis suggests that the use of β-blockers, especially cardioselective β-blockers, should not be contraindicated in patients with COPD.

Establishment and characterization of a new and stable collagen-binding assay for the assessment of von Willebrand factor activity

Introduction

Laboratory diagnosis of von Willebrand disease (VWD) requires determination of both von Willebrand factor (VWF) protein levels and activity. Current VWF activity tests include the ristocetin cofactor assay and the collagen-binding assay (VWF:CB). The goal of this investigation is to characterize a new collagen-binding assay and to determine its effectiveness in identifying VWD.

Methods

Analytical studies were carried out to characterize the performance of a new VWF:CB ELISA. Additionally, samples from a normal population were tested as were well-characterized type 1 and type 2 VWD samples.

Results

Repeatability and within-laboratory precision studies resulted in coefficients of variation (CVs) of ≤11%. A linear range of 1–354% (0.01–3.54 IU/mL) was determined, along with a limit of detection and a lower limit of quantitation of 1.6% and 4.0% (0.016 and 0.04 IU/mL), respectively. Samples tested from apparently healthy individuals resulted in a normal range of 54–217% (0.54–2.17 IU/mL). Known VWD type 1 and type 2 samples were also analyzed by the ELISA, with 99% of samples having VWF:CB below the normal reference range and an estimated 96% sensitivity and 87% specificity using a VWF collagen-binding/antigen cutoff ratio of 0.50.

Conclusion

This new VWF:CB ELISA provides an accurate measure of collagen-binding activity that aids in the diagnosis and differentiation of type 1 from type 2 VWD.

In ovo leptin administration inhibits chorioallantoic membrane angiogenesis in female chicken embryos through the STAT3-mediated vascular endothelial growth factor (VEGF) pathway

Previous studies indicate that leptin regulates placental angiogenesis and fetal growth in mammals and that in ovo leptin administration affects embryonic development and hatch weight in the chicken. To test the hypothesis that leptin affects embryonic growth through modifying chorioallantoic membrane (CAM) angiogenesis, we injected 0.5 μg of recombinant murine leptin into the albumen of fertilized eggs before incubation. On embryonic day 12 (E12), the number and the total area of blood vessels on CAM were measured, and expression of genes involved in angiogenesis was quantitated to show the possible mechanisms. Leptin in ovo administration decreased (P < 0.05) both the total area of blood vessels and the number of small-sized capillaries on CAM of E12 female chicken embryos, which coincided with significantly decreased (P < 0.05) embryo weight on E12 and BW at hatching. Vascular endothelial growth factor (VEGF) and inducible and endothelial nitric oxide synthases (iNOS and eNOS) were all downregulated (P < 0.05) in CAM both at the mRNA and protein/activity levels with reduced (P < 0.05) nitric oxide (NO) concentration in chorioallantoic fluid of female embryos. Furthermore, signal transducer and activator of transcription-3 (STAT3) was found to be diminished (P < 0.05) both at the mRNA and protein levels and associated with decreased (P < 0.05) binding of STAT3 to VEGF promotor in the CAM of leptin-treated E12 female embryos. These data suggest that in ovo leptin administration affects CAM angiogenesis and embryo growth in female chicken embryos, probably through STAT3-mediated VEGF/NO pathways.