A new adenoviral vector (Ad-GFAP-GDNF) (Ad-¼ adenovirus, GFAP ¼ glial fibrillary acidic protein, GDNF ¼ glial cell line-derived neurotrophic factor) was constructed in which (i) the E1,E3/E4 regions of Ad5 were deleted and (ii) the GDNF transgene is driven by the GFAP promoter. We verified, in vitro, that the recombinant GDNF was expressed in primary cultures of astrocytes. In vivo, the Ad-GFAP-GDNF was injected into the striatum of rats 1 week before provoking striatal 6-OHDA lesion. After 1 month, the striatal GDNF levels were 37 pg/mg total protein. This quantity was at least 120-fold higher than in nontransduced striatum or after injection of the empty adenoviral vector. At 3 months after viral injection, GDNF expression decreased, whereas the viral DNA remained unchanged. Furthermore, around 70% of the dopaminergic (DA) neurons were protected from degeneration up to 3 months as compared to about 45% in the control groups. In addition, the amphetamine-induced rotational behavior was decreased. The results obtained in this study on DA neuron protection and rotational behavior are similar to those previously reported using vectors with viral promoters. In addition to these results, we established that a high level of GDNF was present in the striatum and that the period of GDNF expression was prolonged after injection of our adenoviral vector.

The transfer of the Glial cell line-derived neurotrophic factor (GDNF) gene to the central nervous system by a recombinant adenoviral vector (Ad) was studied. We constructed the adenovirus vector Ad-NSE-GDNF from which the E1, E3/E4 regions of Ad5 have been deleted and in which the GDNF gene was under the control of a neuron-specific enolase (NSE) promoter. The vector was injected into the striatum of a rat model of Parkinson's disease. We found that (i) the NSE promoter can restrict transgene expression in neurons; (ii) Ad-NSE-GDNF significantly protected dopaminergic (DA) neurons in the substantia nigra (SN) but did not reverse the impairments of amphetamine-induced rotational behavior in lesioned rats.

Basal lamina components, such as heparan sulfate proteoglycan (HSPG) and laminin play an important role in neuritic outgrowth for CNS and PNS neurons in culture. The mutant mouse 'Trembler' is characterized by hypomyelinization and production of an excess of basal lamina layers around Schwann cells in peripheral nerves. In order to analyse whether or not the serum of the mutant animals contains neurite outgrowth-promoting factors, we cultured rat spinal cord neurons in the presence of Trembler serum. Under these conditions, the outgrowth of neurites was increased approx. 2 times as compared to control serum. Trembler serum induces neuritic outgrowth characterized both by an increase in number of primary neurites emerging from the nerve cell body as well as by an increase in peripheral branching of neurites. To characterize the factors implicated in this increase we added antibodies directed against HSPG or laminin to the mutant serum. As a result, the increase in neuritic outgrowth was reduced or abolished in both cases. Trembler effect on neurite growth disappeared when the number of the non-neuronal cells was reduced, suggesting that the mutant serum did not act directly on neurons but by the intermediary action of non-neuronal cells.

Trembler mouse, a Schwann cell mutation, is characterized by severe hypomyelination of peripheral nerves, high Schwann cell proliferation and the presence of a multilayered basal lamina which surrounds them. In contrast with their continuous in vivo division, mutant Schwann cells prepared from 15-day sciatic nerves display a lower proliferation rate in cell culture than normal Schwann cells. However, quiescent Trembler Schwann cells are still able to respond, as normal Schwann cells, to exogenous mitogens, such as nerve extracts and myelin-enriched fractions. In addition, both normal and Trembler Schwann cells proliferate in response to Trembler serum. Fibroblast growth factor is not the mitogenic factor which stimulates mutant Schwann cell proliferation in vivo, since it is absent in Trembler serum and poorly concentrated in Trembler adult sciatic nerves. Our results suggest that, in vivo, the serum of Trembler mouse probably contains mitogenic factors, not yet characterized, which may trigger the permanent division of mutant Schwann cells, in contrast to the quiescent state of these cells in the nerves of normal mice.

Bisphenol A (BPA) has been considered as a weak environmental estrogen, as similar to estradiol that has a potential in stimulating some cellular responses and phenotype changes. In addition, the ecological impacts of BPA to aquatic organisms have been increasingly raised at environmental relevant concentrations that potentially may affect to human health at earlylife. This study used 3-day old zebrafish larvae (Danio rerio) as a model for toxicological testing. The semistatic testing was conducted to investigate the effects of different BPA concentrations (5 mg/L, 6 mg/L, 7 mg/L, 8 mg/L and 9 mg/L) that induced morphorlogical and physiological changes during the early development. As the results, the LC 50-24hrs , LC 50-48hrs , LC 50-72hrs and LC 50-96hrs were determined as 9.503 mg/L, 8.688 mg/L, 7.328 mg/L and 6.669 mg/L, respectively. Phenotypic analysis revealed that toxicity caused cardiac edema. The result obtained from this research provided relevant information for environmental and human risk assessments.

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Bisphenol A (BPA) is an endocrine-disrupting compound found in the environment as well as in the plastic food containers for human use. Most impact of this compound to animals is acute toxicity to the liver of young individuals, but little is known about chronic toxicity to the adult liver. Here we report that, when adult zebrafish were exposed to various concentration of bisphenol A for 60 days, we have the number of liver protein spots in 2D-PAGE gels was reduced to 15-25%. Protein identification by HPLC-ESI (electron spray ionization) revealed that sixteen 2D-PAGE spots were remarkably altered and majority of them are related to metabolic energy system; e.g., liver basic L-lactate dehydrogenase B-B chain, ATP synthase subunit beta, and intracellular fatty acid-binding proteins. Besides, heat shock protein 60kDa 1 (HSPD1), which is known to  associate with inflammation, was over-expressed in fish liver after exposure to 100 µg/l BPA, but not at lower concentrations of BPA. Thus, chronic exposure to environmental BPA may cause liver dysfunctions. Sixteen hepatic proteins identified in this study would be potential biomarkers for chronic BPA toxicity.   Citation: Ngo Thi Mai, Do Hong Lan Chi, Le Phi Nga, 2017. A proteomic analyses to assess the effects of chronic exposure of bisphenol a to adult zebrafish (Danio rerio). Tap chi Sinh hoc, 39(3): 333-341. DOI: 10.15625/0866-7160/v39n3.98995. *Corresponding author: lephinga1@hotmail.com, lephinga@hcmut.edu.vn Received 12 December 2016, accepted 20 August 2017