RESUMO
This work aims at investigating the neuroprotective effects of neuroglobin (Ngb) in vivo and in vitro. RT-PCR and Western blotting were used to examine Ngb mRNA and protein levels in the mouse cortex after acute and repeated exposure to hypoxia. The cDNAs of mouse Ngb were cloned and transfected into SH-SY5Y cells to examine Ngb function in vitro. Expression of Ngb and mRNA was upregulated in the cortex of mice preconditioned by repetitive exposure to hypoxia. Tolerance to hypoxia of Ngb-transformed SH-SY5Y cells was enhanced. These results suggest that Ngb might be involved in hypoxic preconditioning which protects neurons from hypoxic injury.
Assuntos
Citoproteção/genética , Globinas/genética , Globinas/metabolismo , Hipóxia Encefálica/genética , Hipóxia Encefálica/metabolismo , Precondicionamento Isquêmico , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Animais , Linhagem Celular Tumoral , Córtex Cerebral/metabolismo , Córtex Cerebral/fisiopatologia , Modelos Animais de Doenças , Regulação da Expressão Gênica/fisiologia , Humanos , Hipóxia Encefálica/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neuroglobina , Neurônios/metabolismo , Oxigênio/metabolismo , RNA Mensageiro/metabolismo , Transfecção , Regulação para Cima/fisiologiaRESUMO
The proliferative activity of neural precursors from the subventricular zone (SVZ) was investigated after a unilateral lesion was formed in the nigrostriatal pathway in adult rats. The lesion was formed by unilateral injection of 6-hydroxydopamine (6-OHDA) into the nigrostriatal pathway, and then bromodeoxyuridine (BrdU) was injected (ip) for 4 days or 2 weeks 10 days after the lesion was formed. The rats were killed, and the brain sections were immunohistochemically stained to detect the expression of BrdU, polysialylated neural-cell-adhesion molecule (PSA-NCAM), glial fibrillary acidic protein (GFAP) and tyrosine hydroxylase (TH) in the SVZ and the striatum (STR). The results showed that the BrdU(+) cells increased significantly in the SVZ, ipsilateral to the lesion at 2 weeks after the lesion. The PSA-NCAM(+) and GFAP(+) cells were also increased in the SVZ at this time. Some BrdU-labeled cells were seen in the same side of the STR and were double-labeled with PSA-NCAM. These cells had a tendency to migrate from the SVZ to the STR. The number of positive cells decreased at 4 weeks after the lesion was formed. The number of nigrostriatal projections with TH(+) decreased significantly in the STR on the lesion side, and the level of decrease was related to the quantity of BrdU-labeled cells at 2 weeks. These results indicate that the neural precursors in the SVZ of adult rats may increase after a lesion has been formed in the nigrostriatal pathway, and these cells might migrate into the STR on the same side.
