Cell survival controlled by lens-derived Sema3A-Nrp1 is vital on caffeine-suppressed corneal innervation during chick organogenesis.

In this study, we investigated the effect of caffeine overexposure on corneal innervation in the early chicken embryo. Caffeine administration restricted corneal innervation by affecting trigeminal nerve development. Immunohistochemistry for phospho-Histone3 (pHIS3) and C-caspase3 revealed that cell survival was repressed by caffeine administration. Whole-mount in situ hybridization against semaphorin 3A (Sema3A) and neuropilin-1 (Nrp1) showed that both caffeine and 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH, a free radical generator) administration upregulates the expression of both Sema3A and Nrp1. Next, we demonstrated that lens ablation in the developing chicken embryos significantly affected NF-labeled periocular nerve fascicles and innervation to the central eye region. Subsequently, we used a neuroblastoma cell line to investigate in vitro whether or not Sema3A-Nrp1 signaling exerts a key role on the caffeine-suppressed neuron survival. Knocking-down Sema3A through transfection with Sema3A-siRNA dramatically decreased the responsiveness of cells to caffeine administration, as well as cell apoptosis. We suggest that Sema3A-Nrp1 signaling regulates Trp53 and Cdkn1a through Slit2-Robo1 and Ephb2. Taken together, we speculate here that caffeine-enhanced reactive oxygen species upregulates Sema3A-Nrp1 expression in the lens and periocular tissues, resulting in corneal cell apoptosis, accompanied by its chemorepellent role on the invasion of the developing cornea by trigeminal sensory fibers.

Exposure to Excess Phenobarbital Negatively Influences the Osteogenesis of Chick Embryos.

Phenobarbital is an antiepileptic drug that is widely used to treat epilepsy in a clinical setting. However, a long term of phenobarbital administration in pregnant women may produce side effects on embryonic skeletogenesis. In this study, we aim to investigate the mechanism by which phenobarbital treatment induces developmental defects in long bones. We first determined that phenobarbital treatment decreased chondrogenesis and inhibited the proliferation of chondrocytes in chick embryos. Phenobarbital treatment also suppressed mineralization in both in vivo and in vitro long bone models. Next, we established that phenobarbital treatment delayed blood vessel invasion in a cartilage template, and this finding was supported by the down-regulation of vascular endothelial growth factor in the hypertrophic zone following phenobarbital treatment. Phenobarbital treatment inhibited tube formation and the migration of human umbilical vein endothelial cells. In addition, it impaired angiogenesis in chick yolk sac membrane model and chorioallantoic membrane model. In summary, phenobarbital exposure led to shortened lengths of long bones during embryogenesis, which might result from inhibiting mesenchyme differentiation, chondrocyte proliferation, and delaying mineralization by impairing vascular invasion.

Effects of oxidative stress on hyperglycaemia-induced brain malformations in a diabetes mouse model.

Pregestational diabetes mellitus (PGDM) enhances the risk of fetal neurodevelopmental defects. However, the mechanism of hyperglycaemia-induced neurodevelopmental defects is not fully understood. In this study, several typical neurodevelopmental defects were identified in the streptozotocin-induced diabetes mouse model. The neuron-specific class III beta-tubulin/forkhead box P1-labelled neuronal differentiation was suppressed and glial fibrillary acidic protein-labelled glial cell lineage differentiation was slightly promoted in pregestational diabetes mellitus (PGDM) mice. Various concentrations of glucose did not change the U87 cell viability, but glial cell line-derived neurotrophic factor expression was altered with varying glucose concentrations. Mouse maternal hyperglycaemia significantly increased Tunel(+) apoptosis but did not dramatically affect PCNA(+) cell proliferation in the process. To determine the cause of increased apoptosis, we determined the SOD activity, the expression of Nrf2 as well as its downstream anti-oxidative factors NQO1 and HO1, and found that all of them significantly increased in PGDM fetal brains compared with controls. However, Nrf2 expression in U87 cells was not significantly changed by different glucose concentrations. In mouse telencephalon, we observed the co-localization of Tuj-1 and Nrf2 expression in neurons, and down-regulating of Nrf2 in SH-SY5Y cells altered the viability of SH-SY5Y cells exposed to high glucose concentrations. Taken together, the data suggest that Nrf2-modulated antioxidant stress plays a crucial role in maternal hyperglycaemia-induced neurodevelopmental defects.

Nrf2 signalling and autophagy are involved in diabetes mellitus-induced defects in the development of mouse placenta.

It is widely accepted that diabetes mellitus impairs placental development, but the mechanism by which the disease operates to impair development remains controversial. In this study, we demonstrated that pregestational diabetes mellitus (PGDM)-induced defects in placental development in mice are mainly characterized by the changes of morphological structure of placenta. The alteration of differentiation-related gene expressions in trophoblast cells rather than cell proliferation/apoptosis is responsible for the phenotypes found in mouse placenta. Meanwhile, excess reactive oxygen species (ROS) production and activated nuclear factor erythroid2-related factor 2 (Nrf2) signalling were observed in the placenta of mice suffering from PGDM. Using BeWo cells, we also demonstrated that excess ROS was produced and Nrf2 signalling molecules were activated in settings characterized by a high concentration of glucose. More interestingly, differentiation-related gene expressions in trophoblast cells were altered when endogenous Nrf2 expression is manipulated by transfecting Nrf2-wt or Nrf2-shRNA. In addition, PGDM interferes with autophagy in both mouse placenta and BeWo cells, implying that autophagy is also involved, directly or indirectly, in PGDM-induced placental phenotypes. Therefore, we revealed that dysfunctional oxidative stress-activated Nrf2 signalling and autophagy are probably responsible for PGDM-induced defects in the placental development of mice. The mechanism was through the interference with differentiation-related gene expression in trophoblast cells.

Proper autophagy is indispensable for angiogenesis during chick embryo development.

People have known that autophagy plays a very important role in many physiological and pathological events. But the role of autophagy on embryonic angiogenesis still remains obscure. In this study, we demonstrated that Atg7, Atg8 and Beclin1 were expressed in the plexus vessels of angiogenesis at chick yolk sac membrane and chorioallantoic membrane. Interfering in autophagy with autophagy inducer or inhibitor could restrict the angiogenesis in vivo, which might be driven by the disorder of angiogenesis-related gene expressions, and also lead to embryonic hemorrhage, which was due to imperfection cell junctions in endothelial cells including abnormal expressions of tight junction, adheren junction and desmosome genes. Using HUVECs, we revealed that cell viability and migration ability changed with the alteration of cell autophagy exposed to RAPA or 3-MA. Interestingly, tube formation assay showed that HUVECs ability of tube formation altered with the change of Atg5, Atg7 and Atg8 manipulated by the transfection of their corresponding siRNA or plasmids. Moreover, the lost cell polarity labeled by F-actin and the absenced ß-catenin in RAPA-treated and 3-MA-treated cell membrane implied intracellular cytoskeleton alteration was induced by the activation and depression of autophagy. Taken together, our current experimental data reveal that autophagy is really involved in regulating angiogenesis during embryo development.

Ethanol exposure represses osteogenesis in the developing chick embryo.

It is known that excess alcohol consumption during pregnancy can increase the risk of fetal alcohol spectrum disorder (FASD). However, the effect of ethanol exposure on bone morphogenesis in fetus is largely unknown. In this study, we demonstrated that ethanol treatment of gastrulating chick embryos could inhibit long bone (humerus, radius and ulna) development. Histological examination revealed that ethanol exposure reduced the width of the proliferation and hypertrophic zones. In addition, cell proliferation and alkaline phosphatase activities were repressed. We also investigated the effect on chondrogenesis and chondrogenesis was inhibited. Ethanol exposure also induced excess reactive oxygen species (ROS) production and altered the expression of osteogenesis-related genes. The inhibiting effect on flat bone (sclerotic ossicle) and the generation of cranial neural crest cells (progenitors of craniofacial bones) was also presented. In conclusion, ethanol exposure during the embryonic period retards bone development through excess ROS production and altered bone-associated gene expression.

Dexamethasone Exposure Accelerates Endochondral Ossification of Chick Embryos Via Angiogenesis.

Dexamethasone (Dex) is widely used to treat chronic inflammatory diseases in the clinic. Increasingly, there is more attention being paid to the side effect of Dex. In this study, we investigated the involvement and mechanism of Dex exposure in accelerating mineralization during long bone formation. We first determined that Dex exposure could accelerate long bone mineralization in vivo, but there was no apparent difference between control and Dex-treated in the phalanges model in vitro. Next, we established that Dex exposure promoted angiogenesis in the chick yolk sac membrane model. In addition, it increased human umbilical vein endothelial cell proliferation and migration in culture. We found that Dex could enhance angiogenesis when phalanges were cultured on chick chorioallantoic membrane and correspondingly increased the expression of angiogenesis-related genes in the phalanges. Furthermore, we also revealed that Dex exposure reduced the number of osteoblasts and simultaneously increased the number of osteocytes in ex vivo-cultured phalanges. Runx-2 and Col10α1 expressions were up-regulated by Dex exposure, indicating that Dex exposure accelerated the terminal differentiation of osteoblasts. Lastly, we demonstrated that MC3T3-E1 cells cultured in the presence of Dex accelerated their mineralization. In summary, we have shown that the ability of Dex to initiate angiogenesis is the mechanism that allows it to accelerate mineralization during long bone formation.

Acute and sub-chronic toxicity of tetrandrine in intravenously exposed female BALB/c mice.

OBJECTIVE: To evaluate the acute and sub-chronic toxicity of intravenously administered tetrandrine (TET) in female BALB/c mice. METHODS: The median lethal dose (LD50) of intravenously administered TET was calculated in mice using Dixon's up-and-down method. In the acute toxicity study, mice were intravenously administered with TET at a single dose of 20, 100, 180, 260 and 340 mg/kg, respectively and were evaluated at 14 days after administration. In the sub-acute toxicity study, mice were intravenously administered various doses of TET (30, 90 and 150 mg/kg) each day for 14 consecutive days. Clinical symptoms, mortality, body weight, serum biochemistry, organ weight and histopathology were examined at the end of the experiment, as well as after a 1-week recovery period. RESULT: LD50 was found to be 444.67±35.76 mg/kg. In the acute toxicity study, no statistically signifificant differences in body weight, blood biochemistry, or organ histology were observed between the administration and control groups when mice were intravenously administered with single dose at 20, 100, 180, 260 and 340 mg/kg of TET (P >0.05). In the sub-acute toxicity study, no signifificant changes in body weight, biochemistry and organ histology were observed with up to 90 mg/kg of TET compared with the control group (P >0.05), however, in the 150 mg/kg administered group, TET induced transient toxicity to liver, lungs and kidneys, but withdrawal of TET can lead to reversal of the pathological conditions. CONCLUSIONS: The overall fifindings of this study indicate that TET is relatively non-toxic from a single dose of 20, 100, 180, 260 or 340 mg/kg, and that up to 90 mg/kg daily for 14 consecutive days can be considered a safe application dose.

Angiogenesis is repressed by ethanol exposure during chick embryonic development.

It is now known that excess alcohol consumption during pregnancy can cause fetal alcohol syndrome to develop. However, it is not known whether excess ethanol exposure could directly affect angiogenesis in the embryo or angiogenesis being indirectly affected because of ethanol-induced fetal alcohol syndrome. Using the chick yolk sac membrane (YSM) model, we demonstrated that ethanol exposure dramatically inhibited angiogenesis in the YSM of 9-day-old chick embryos, in a dose-dependent manner. Likewise, the anti-angiogenesis effect of ethanol could be seen in the developing vessel plexus (at the same extra-embryonic regions) during earlier stages of embryo development. The anti-angiogenic effect of ethanol was found associated with excess reactive oxygen species (ROS) production; as glutathione peroxidase activity increased while superoxide dismutase 1 and 2 activities decreased in the YSMs. We further validated this observation by exposing chick embryos to 2,2'-azobis-amidinopropane dihydrochloride (a ROS inducer) and obtained a similar anti-angiogenesis effect as ethanol treatment. Semiquantitative reverse transcription-polymerase chain reaction analysis of the experimental YSMs revealed that expression of angiogenesis-related genes, vascular endothelial growth factor and its receptor, fibroblast growth factor 2 and hypoxia-inducible factor, were all repressed following ethanol and 2,2'-azobis-amidinopropane dihydrochloride treatment. In summary, our results suggest that excess ethanol exposure inhibits embryonic angiogenesis through promoting superfluous ROS production during embryo development.

Investigating the effect of excess caffeine exposure on placental angiogenesis using chicken 'functional' placental blood vessel network.

It is now known that over-consumption of caffeine by pregnant mothers could have detrimental effects on normal fetal development. However, it remains obscure how caffeine's harmful effect impacts directly or indirectly on the developing embryo/fetus through damaging placenta development. In this study, we demonstrated the morphological similarities between the yolk sac and chorioallantoic membranes (CAM) of chick embryos and the villi of the mammalian placenta. Using the chick yolk sac and the CAM as a model, we found that 5-15 µmol per egg of caffeine exposure inhibited angiogenesis. Under the same condition, cell proliferation in extraembryonic mesoderm was reduced while apoptosis was enhanced. Semi-quantitative RT-PCR analysis revealed that caffeine treatment down-regulated VEGF, VEGFR2, PIGF, IGF2 and NRP1 expression, but up-regulated Ang1 and Ang2 expression. We performed in situ hybridization to show VE-cadherin expression and as to demonstrate the blood vessels in the CAM and yolk sac membranes. This distribution of the VE-cadherin(+) blood vessels was determined to be reduced after caffeine treatment. Furthermore, MDA activity was induced after caffeine exposure, but GSH-PX activity was inhibited after caffeine exposure; SOD activity was unchanged as compared with the control. In summary, our results suggest that caffeine exposure could negatively impact on angiogenesis in the chick yolk sac and CAM by targeting angiogenesis-related genes. Some of these genes are also involved in regulating excess ROS generation. The results implied that the negative impact of caffeine on fetal development was partly attributed to impaired placental angiogenesis.

High glucose environment inhibits cranial neural crest survival by activating excessive autophagy in the chick embryo.

High glucose levels induced by maternal diabetes could lead to defects in neural crest development during embryogenesis, but the cellular mechanism is still not understood. In this study, we observed a defect in chick cranial skeleton, especially parietal bone development in the presence of high glucose levels, which is derived from cranial neural crest cells (CNCC). In early chick embryo, we found that inducing high glucose levels could inhibit the development of CNCC, however, cell proliferation was not significantly involved. Nevertheless, apoptotic CNCC increased in the presence of high levels of glucose. In addition, the expression of apoptosis and autophagy relevant genes were elevated by high glucose treatment. Next, the application of beads soaked in either an autophagy stimulator (Tunicamycin) or inhibitor (Hydroxychloroquine) functionally proved that autophagy was involved in regulating the production of CNCC in the presence of high glucose levels. Our observations suggest that the ERK pathway, rather than the mTOR pathway, most likely participates in mediating the autophagy induced by high glucose. Taken together, our observations indicated that exposure to high levels of glucose could inhibit the survival of CNCC by affecting cell apoptosis, which might result from the dysregulation of the autophagic process.

The impact of high-salt exposure on cardiovascular development in the early chick embryo.

In this study, we show that high-salt exposure dramatically increases chick mortality during embryo development. As embryonic mortality at early stages mainly results from defects in cardiovascular development, we focused on heart formation and angiogenesis. We found that high-salt exposure enhanced the risk of abnormal heart tube looping and blood congestion in the heart chamber. In the presence of high salt, both ventricular cell proliferation and apoptosis increased. The high osmolarity induced by high salt in the ventricular cardiomyocytes resulted in incomplete differentiation, which might be due to reduced expression of Nkx2.5 and GATA4. Blood vessel density and diameter were suppressed by exposure to high salt in both the yolk sac membrane (YSM) and chorioallantoic membrane models. In addition, high-salt-induced suppression of angiogenesis occurred even at the vasculogenesis stage, as blood island formation was also inhibited by high-salt exposure. At the same time, cell proliferation was repressed and cell apoptosis was enhanced by high-salt exposure in YSM tissue. Moreover, the reduction in expression of HIF2 and FGF2 genes might cause high-salt-suppressed angiogenesis. Interestingly, we show that high-salt exposure causes excess generation of reactive oxygen species (ROS) in the heart and YSM tissues, which could be partially rescued through the addition of antioxidants. In total, our study suggests that excess generation of ROS might play an important role in high-salt-induced defects in heart and angiogenesis.

Investigating the Mechanism of Hyperglycemia-Induced Fetal Cardiac Hypertrophy.

Hyperglycemia in diabetic mothers enhances the risk of fetal cardiac hypertrophy during gestation. However, the mechanism of high-glucose-induced cardiac hypertrophy is not largely understood. In this study, we first demonstrated that the incidence rate of cardiac hypertrophy dramatically increased in fetuses of diabetic mothers using color ultrasound examination. In addition, human fetal cardiac hypertrophy was successfully mimicked in a streptozotocin (STZ)-induced diabetes mouse model, in which mouse cardiac hypertrophy was diagnosed using type-M ultrasound and a histological assay. PH3 immunofluorescent staining of mouse fetal hearts and in vitro-cultured H9c2 cells indicated that cell proliferation decreased in E18.5, E15.5 and E13.5 mice, and cell apoptosis in H9c2 cells increased in the presence of high glucose in a dose-dependent manner. Next, we found that the individual cardiomyocyte size increased in pre-gestational diabetes mellitus mice and in response to high glucose exposure. Meanwhile, the expression of ß-MHC and BMP-10 was up-regulated. Nkx2.5 immunofluorescent staining showed that the expression of Nkx2.5, a crucial cardiac transcription factor, was suppressed in the ventricular septum, left ventricular wall and right ventricular wall of E18.5, E15.5 and E13.5 mouse hearts. However, cardiac hypertrophy did not morphologically occur in E13.5 mouse hearts. In cultured H9c2 cells exposed to high glucose, Nkx2.5 expression decreased, as detected by both immunostaining and western blotting, and the expression of KCNE1 and Cx43 was also restricted. Taken together, alterations in cell size rather than cell proliferation or apoptosis are responsible for hyperglycemia-induced fetal cardiac hypertrophy. The aberrant expression of Nkx2.5 and its regulatory target genes in the presence of high glucose could be a principal component of pathogenesis in the development of fetal cardiac hypertrophy.

An in vitro and in vivo study on the synergistic effect and mechanism of itraconazole or voriconazole alone and in combination with tetrandrine against Aspergillus fumigatus.

In this study, we investigated the in vitro antifungal effects of itraconazole/voriconazole (ITR/VRC) alone and in combination with tetrandrine (TET) against 23 clinical isolates of A. fumigatus using a chequerboard microdilution method. The dynamic antifungal effects of TET with ITR/VRC against A. fumigatus were assessed in vivo using time-kill curves following systemic infection of mice with A. fumigatus. After treatment, efflux pump activity was determined by the efflux of rhodamine 6G (R6G). When ITR was combined with TET, ITR MICs were reduced from 0.125-32 to 0.0625-2 µg ml(-1), and TET MICs were reduced from 256-512 to 8-64 µg ml(-1). When VRC was combined with TET, VRC MICs were reduced from 0.125-2 to 0.03125-0.5 µg ml(-1), and TET MICs were reduced from 256-512 to 8-256 µg ml(-1). Time-kill curves revealed that A. fumigatus viability was reduced after treatment with ITR/VRC combined with TET versus ITR/VRC alone. ITR/VRC combined with TET significantly prolonged mouse survival and reduced kidney and brain tissue burdens versus ITR/VRC alone (P < 0.05). Moreover, TET inhibited R6G efflux of A. fumigatus. Thus, in vitro and in vivo, TET acted synergistically with ITR/VRC against A. fumigatus, and the synergistic mechanism was related to inhibition of the drug efflux pump.

Tetrandrine suppresses human glioma growth by inhibiting cell survival, proliferation and tumour angiogenesis through attenuating STAT3 phosphorylation.

Tetrandrine (Tet), a bisbenzylisoquinoline alkaloid, has been reported to possess anti-tumour activity. However, its effects on human glioma remain unknown. In this study, we demonstrated that Tet inhibited human glioma cell growth in vitro and in vivo. It has been hypothesised that Tet inhibits glioma growth by affecting glioma cell survival, proliferation and vasculature in and around the xenograft tumour in the chick CAM model and signal transducer and activator of transcription 3 (STAT3) mediated these activities. Therefore, we conducted a detailed analysis of the inhibitory effects of Tet on cell survival using a TUNEL assay and flow cytometric analysis; on cell proliferation based on the expression of proliferating cell nuclear antigen; and on angiogenesis using a CAM anti-angiogenesis assay. We used western blotting to investigate the role of STAT3 on the anti-glioma activities of Tet. The results revealed that Tet inhibited survival and proliferation in human glioma cells, impaired tumour angiogenesis and decreased the expression of phosphorylated STAT3 and its downstream proteins. In sum, our data indicate that STAT3 is involved in Tet-induced the regression of glioma growth by activating tumour cell apoptosis, inhibiting glioma cell proliferation and inhibiting angiogenesis.

Biphasic influence of dexamethasone exposure on embryonic vertebrate skeleton development.

Dexamethasone (Dex) has anti-inflammatory and immunomodulatory properties against many conditions. There is a potential teratogenic risk, however, for pregnant women receiving Dex treatment. It has been claimed that Dex exposure during pregnancy could affect osteogenesis in the developing embryo, which still remains highly controversial. In this study, we employed chick embryos to investigate the effects of Dex exposure on skeletal development using combined in vivo and in vitro approach. First, we demonstrated that Dex (10(-8)-10(-6)µmol/egg) exposure resulted in a shortening of the developing long bones of chick embryos, and it accelerated the deposition of calcium salts. Secondly, histological analysis of chick embryo phalanxes exhibited Dex exposure inhibited the proliferation of chondrocytes, increased apoptosis of chondrocytes and osteocytes, and led to atypical arranged hypertrophic chondrocytes. The expression of genes related to skeletogenesis was also analyzed by semi-quantitative RT-PCR. The expression of ALP, Col1a2 and Col2a1 was decreased in the Dex treated phalanxes. A detectable increase was observed in Runx-2 and Mmp-13 expression. We next examined how Dex affected the different stages of skeletogenesis in vitro. Utilizing limb bud mesenchyme micromass cultures, we determined that Dex exposure exerted no effect on apoptosis but impaired chondrogenic cell proliferation. Interestingly, low dose of Dex moderately prompted nodule formation as revealed by alcian blue staining, but higher doses of Dex significantly inhibited similar chondrogenic differentiation. Dex exposure did not induce apoptosis when the chondrogenic precursors were still at the mesenchymal stage, however, cell viability was suppressed when the mesenchyme differentiated into chondrocytes. Alizarin red staining revealed that the capacity to form mineralized bone nodules was correspondingly enhanced as Dex concentrations increased. The mRNA level of Sox-9 was slightly increased in mesenchymal cell mass treated by low concentration of Dex. Mmp-13 expression was obviously up-regulated by Dex in both mesenchymal cells and primary chondrocyte cultures. And Col10a1 expression was also increased by Dex exposure in chondrocyte. In summary, we have revealed that different concentrations of Dex exposure during early gestation could exert a biphasic effect on vertebrate skeletal development.

Effects of high salt-exposure on the development of retina and lens in 5.5-day chick embryo.

BACKGROUND/AIMS: Excess maternal salt intake during pregnancy may alter fetal development. However, our knowledge on how an increased salt intake during pregnancy influences fetal eye development is limited. In this study, we investigated the effects of high-salt treatment on the developing eyes in chick embryos, especially focusing on the development of the retina and the lens. METHODS: 5.5-day chick embryos were exposed to 280mosm/l (n=17), or 300mosm/l (n=16) NaCl. The treated embryos were then incubated for 96 hours before they were fixed with 4% paraformaldehyde for H&E staining, whole-mount embryo immunostaining and TUNEL staining. BrdU and PH3 incorporation experiments were performed on the chick embryos after high-salt treatment. RT-PCR analyses were conducted from chick retina tissues. RESULTS: We demonstrated that high-salt treatment altered the size of eyes in chick embryos, induced malformation of the eyes and impaired the development of the lens and the retina. We found an impaired expression of Paired box 6 (PAX6) and neuronal cells in the developing retina as revealed by neurofilament immunofluorescent staining. There was a reduction in the number of BrdU-positive cells and PH3-positive cells in the retina, indicating an impaired cell proliferation with high-salt treatment. High-salt treatment also resulted in an increased number of TUNEL-positive cells in the retina, indicating a higher amount of cell death. RT-PCR data displayed that the expression of the pro-apoptotic molecule nerve growth factor (NGF) in chick retina was increased and CyclinD1 was reduced with high-salt treatment. The size of the lens was reduced and Pax6 expression in the lens was significantly inhibited. High salt-treatment was detrimental to the migration of neural crest cells. CONCLUSION: Taken together, our study demonstrated that high-salt exposure of 5.5-day chick embryos led to an impairment of retina and lens development, possibly through interfering with Pax6 expression.

Adverse effects of high glucose levels on somite and limb development in avian embryos.

Gestational diabetes has an adverse impact on fetal musculoskeletal development, but the mechanism involved is still not completely understood. In this study, we investigated the effects of high glucose on the developing somites and their derivate using the chick embryo as a model. We demonstrated that under high glucose, the number of generated somites was reduced and their morphology altered in 2-day old chick embryos. In addition, high glucose repressed the development of the limb buds in 5.5-day old chick embryos. We also demonstrated that high glucose abridged the development of the sclerotome and the cartilage in the developing limb bud. The sonic hedgehog (Shh) gene has been reported to play a crucial role in the development and differentiation of sclerotome. Hence, we examined how Shh expression in the sclerotome was affected under high glucose. We found that high glucose treatment significantly inhibited Shh expression. The high glucose also impaired myotome formation at trunk level - as revealed by immunofluorescent staining with MF20 antibodies. In the neural tube, we established that Wnt3a expression was also significantly repressed. In summary, our study demonstrates that high glucose concentrations impair somite and limb bud development in chick embryos, and suggests that Shh and Wnt genes may play a role in the underlying mechanism.

Excess caffeine exposure impairs eye development during chick embryogenesis.

Caffeine has been an integral component of our diet and medicines for centuries. It is now known that over consumption of caffeine has detrimental effects on our health, and also disrupts normal foetal development in pregnant mothers. In this study, we investigated the potential teratogenic effect of caffeine over-exposure on eye development in the early chick embryo. Firstly, we demonstrated that caffeine exposure caused chick embryos to develop asymmetrical microphthalmia and induced the orbital bone to develop abnormally. Secondly, caffeine exposure perturbed Pax6 expression in the retina of the developing eye. In addition, it perturbed the migration of HNK-1(+) cranial neural crest cells. Pax6 is an important gene that regulates eye development, so altering the expression of this gene might be the cause for the abnormal eye development. Thirdly, we found that reactive oxygen species (ROS) production was significantly increased in eye tissues following caffeine treatment, and that the addition of anti-oxidant vitamin C could rescue the eyes from developing abnormally in the presence of caffeine. This suggests that excess ROS induced by caffeine is one of the mechanisms involved in the teratogenic alterations observed in the eye during embryogenesis. In sum, our experiments in the chick embryo demonstrated that caffeine is a potential teratogen. It causes asymmetrical microphthalmia to develop by increasing ROS production and perturbs Pax6 expression.

Enhanced beta-catenin expression and inflammation are associated with human ectopic tubal pregnancy.

STUDY QUESTION: Is there a molecular link between Wnt signaling in fallopian tube inflammation and ectopic tubal implantation? SUMMARY ANSWER: Enhanced beta-catenin expression, reduced E-cadherin expression and glycogen accumulation in the tubal epithelia and hyperplasia in tubal arteries were found in ectopic tubal pregnancy, consistent with the effects induced by Wnt signaling and inflammation. WHAT IS KNOWN ALREADY: Chronic inflammation caused by infection can alter gene expression in the fallopian tube cells possibly leading to the development of ectopic pregnancy. Knockout mouse models have shown a relationship between Wnt/beta-catenin signaling and predisposition to tubal ectopic pregnancy. STUDY DESIGN, SIZE, DURATION: Women with ectopic tubal pregnancy (n = 18) were included in the case group, while women with chronic salpingitis (n = 13) and non-pregnant women undergoing sterilization procedures or salpingectomy for benign uterine disease (n = 10) were set as the controls. This study was performed between January 2012 and November 2012. PARTICIPANTS/MATERIALS, SETTING, METHODS: The ampullary segments of fallopian tubes were collected from patients. Tissues of tubal pregnancy were separated into implantation sites and non-implantation sites. Beta-catenin and E-cadherin expression were determined using immunohistological and immunofluorescence staining. Glycogen production was measured with periodic acid Schiff by staining. The diameter and wall thickness of tubal arteries were evaluated by histological analysis method. MAIN RESULTS AND THE ROLE OF CHANCE: Immunohistological staining revealed that beta-catenin protein expression was 100% positive in the ectopic pregnant and inflamed tubal tissues, and the staining intensity was significantly higher than in non-pregnant tubal tissues. In contrast, E-cadherin expression was reduced in ectopic pregnant fallopian tubes, possibly as a consequence of increased Wnt signaling. Moreover, glycogen accumulated in the tubal cells, and hyperplasia was observed in the tubal arteries with ectopic pregnancy, which is consistent with the effects induced by Wnt signaling and inflammation. All these changes could create the permissive environment that promotes embryos to ectopically implant into the fallopian tube. LIMITATIONS, REASONS FOR CAUTION: This finding requires a further confirmation about what activates Wnt signaling in ectopic tubal pregnancies. Also, it is generally recognized that Chlamydia infection is associated with ectopic pregnancy, and disturbs tubal epithelia via the Wnt signaling. However, the infection type in the samples used was salpingitis. WIDER IMPLICATIONS OF THE FINDINGS: A better understanding of the underlying mechanisms leading to ectopic pregnancies may contribute to our knowledge of the pathogenesis of tubal disorders and infertility and to the prevention of tubal ectopic pregnancy.