Evaluation of BDE-47-induced neurodevelopmental toxicity in zebrafish embryos.

There are growing concerns about the neurodevelopmental toxicity of polybrominated diphenyl ethers (PBDEs), but the toxicological phenotypes and mechanisms are not well elucidated. Here, zebrafish (Danio rerio) were exposed to 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) from 4 to 72 h post-fertilization (hpf). The results showed that BDE-47 stimulated the production of dopamine and 5-hydroxytryptamine, but inhibited expression of Nestin, GFAP, Gap43, and PSD95 in 24 hpf embryos. Importantly, we unraveled the inhibitory effects of BDE-47 on neural crest-derived melanocyte differentiation and melanin syntheses process, evidenced by disrupted expression of wnt1, wnt3, sox10, mitfa, tyrp1a, tyrp1b, tryp2, and oca2 gene in 72 hpf embryos and decreased tyrosinase activities in embryos at 48 and 72 hpf. The transcriptional activities of myosin VAa, kif5ba, rab27a, mlpha, and cdc42 genes, which are associated with intracellular transport process, were also disturbed during zebrafish development. Ultimately, these alterations led to fast spontaneous movement and melanin accumulation deficit in zebrafish embryos upon BDE-47 exposure. Our results provide an important extension for understanding the neurodevelopmental effects of PBDEs and facilitate the comprehensive evaluation of neurotoxicity in embryos.

BDE-47 induced apoptosis in zebrafish embryos through mitochondrial ROS-mediated JNK signaling.

2,2,4,4-tetrabromodiphenyl ether (BDE-47) has received considerable attention because of its high detection level in biological samples and potential developmental toxicity. Here, using zebrafish (Danio rerio) as the experimental animal, we investigated developmental effects of BDE-47 and explored the potential mechanism. Zebrafish embryos at 4 h post-fertilization (hpf) were exposed to 0.312, 0.625 and 1.25 mg/L BDE-47 to 74-120 hpf. We found that BDE-47 instigated a dose-related developmental toxicity, evidenced by reduced embryonic survival and hatching rate, shortened body length and increased aberration rate. Meanwhile, higher doses of BDE-47 reduced mitochondrial membrane potential and ATP production but increased apoptosis in zebrafish embryos. Expression of genes involved in mitochondrial oxidative phosphorylation (OXPHOS) (ndufb8, sdha, uqcrc1, cox5ab and atp5fal) were negatively related to BDE-47 doses in zebrafish embryos. Moreover, exposure to BDE-47 at 0.625 or 1.25 mg/L impaired mitochondrial biogenesis and mitochondrial dynamics. Our data further showed that BDE- 47 exposure induced excessive reactive oxygen species (ROS) and oxidative stress, which was accompanied by the activation of c-Jun N-terminal Kinase (JNK). Antioxidant NAC and JNK inhibition could mitigate apoptosis in embryos and improve embryonic development in BDE-47-treated zebrafish, suggesting the involvement of ROS/JNK pathway in embryonic developmental changes induced by BDE-47. Altogether, our data suggest here that developmental toxicity of BDE-47 may be associated with mitochondrial ROS-mediated JNK signaling in zebrafish embryo.

Erythropoietin-Induced Autophagy Protects Against Spinal Cord Injury and Improves Neurological Function via the Extracellular-Regulated Protein Kinase Signaling Pathway.

The objective of this study was to explore the neuroprotective molecular mechanisms of erythropoietin (EPO) in rats following spinal cord injury (SCI). First, a standard SCI model was established. After drug or saline treatment was administered, locomotor function was evaluated in rats using the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale. H&E, Nissl, and TUNEL staining were performed to assess the ratio of cavities, number of motor neurons, and apoptotic cells in the damaged area. The relative protein and mRNA expressions were examined using western blot and qRT-PCR analyses, and the inflammatory markers, axon special protein, and neuromuscular junctions (NMJs) were detected by immunofluorescence. Both doses of EPO notably improved locomotor function, but high-dose EPO was more effective than low-dose EPO. Moreover, EPO reduced the cavity ratio, cell apoptosis, and motor neuron loss in the damaged area, but enhanced the autophagy level and extracellular-regulated protein kinase (ERK) activity. Treatment with an ERK inhibitor significantly prevented the effect of EPO on SCI, and an activator mimicked the benefits of EPO. Further investigation revealed that EPO promoted SCI-induced autophagy via the ERK signaling pathway. EPO activates autophagy to promote locomotor function recovery in rats with SCI via the ERK signaling pathway.

Identification of Sex-Specific Markers Reveals Male Heterogametic Sex Determination in Pseudobagrus ussuriensis.

Comprehending sex determination mechanism is a first step for developing sex control breeding biotechnologies in fish. Pseudobagrus ussuriensis, one of bagrid catfishes in Bagridae, had been observed to have about threefold size dimorphism between males and females, but its sex determination mechanism had been unknown. In this study, we firstly used the amplified fragment length polymorphism (AFLP)-based screening approach to isolate a male-specific DNA fragment and thereby identified a 10,569 bp of male-specific sequence and a 10,365 bp of female-related sequence by genome walking in the bagrid catfish, in which a substantial genetic differentiation with 96.35 % nucleotide identity was revealed between them. Subsequently, a high differentiating region of 650 bp with only 70.26 % nucleotide identity was found from the corresponding two sequences, and three primer pairs of male-specific marker, male and female-shared marker with different length products in male and female genomes, and female-related marker were designed. Significantly, when these markers were used to identify genetic sex of the bagrid catfish, only male individuals was detected to amplify the male-specific marker fragment, and female-related marker was discovered to produce dosage association in females and in males. Our current data provide significant genetic evidence that P. ussuriensis has heterogametic XY sex chromosomes in males and homogametic XX sex chromosomes in females. Therefore, sex determination mechanism of P. ussuriensis is male heterogametic XX/XY system.

[Effects of cold-stress stimulation on filial growth and development of pregnant mice].

AIM: To inspect the effects of cold-stress on filial growth and development of pregnant mice. METHODS: Pregnant mice were divided into pregnant control group(PN) and pregnant cold-stress group (PC). The PC were kept in (4 +/- 2) C from 8:00 to 12:00 every day and the PN were kept in 25 degrees C. After 18 days, the blood pressure of pregnant mice were measured, and the weight of fetus, placenta and amniotic fluid were recorded. The natal mice visceral organs weight, visceral organs weight and body weight ratio were also measured. Growth curve and increment ratio curve of body weight were protracted every day from 1 st day to 44th day. Blood pressure of all filiality were measured in 8 weeks after they were born. RESULTS: The blood pressure in PC was increased than that in PN (P < 0.05), the weight of fetus, placenta and amniotic fluid of PC decreased significantly compared with PN (P < 0.01). The filial visceral organ weight of PC reduced obviously compared with PN (P < 0.05), while the visceral organs weight and body weight ratio had no statistical meanings between the offspring of PC and PN (P > 0.05). Obvious difference of growth curve of the two filial groups was also existed until sexual maturity, but increment ratio curve of body weight of the two filial groups was basically fitted close. Filial blood pressure of PC was evidently higher than that in PN. CONCLUSION: Cold-stress stimulations seriously affect filial growth and development of pregnant mice.

A genomic regulatory network for development.

Development of the body plan is controlled by large networks of regulatory genes. A gene regulatory network that controls the specification of endoderm and mesoderm in the sea urchin embryo is summarized here. The network was derived from large-scale perturbation analyses, in combination with computational methodologies, genomic data, cis-regulatory analysis, and molecular embryology. The network contains over 40 genes at present, and each node can be directly verified at the DNA sequence level by cis-regulatory analysis. Its architecture reveals specific and general aspects of development, such as how given cells generate their ordained fates in the embryo and why the process moves inexorably forward in developmental time.