摘要
Lead ion （Pb2＋） has been proven to be a neurotoxin due to its neurotoxicity on mammalian nervous system, especially for the developing brains of juveniles. However, many reported studies involved the negative effects of Pb2＋ on adult neural cells of humans or other mammals, only few of which have examined the effects of Pb2＋ on neural stem cells. The purpose of this study was to reveal the biological effects of Pb2＋from lead acetate [Pb （0H30OO）2] on viability, proliferation and differentiation of neural stem cells derived from the hippocampus of newborn rats aged 7 days and adult rats aged 90 days, respectively. This study was carried out in three parts. In the first part, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay （MTT viability assay） was used to detect the effects of Pb2＋ on the cell viability of passage 2 hippocampal neural stem cells after 48-hour exposure to 0-200 pM Pb2＋. In the second part, 10 pM bromodeoxyuridine was added into the culture medium of passage 2 hippocampal neural stem cells after 48-hour exposure to 0- 200 pM Pb2＋, followed by immunocytochemical staining with anti-bromodeoxyuridine to demonstrate the effects of Pb2＋ on cell proliferation. In the last part, passage 2 hippocampal neural stem cells were allowed to grow in the differentiation medium with 0-200 pM Pb2＋. Immunocytochemical staining with anti-microtubule-associated protein 2 （a neuron marker）, anti-glial fibrillary acidic protein （an astrocyte marker）, and anti-RIP （an oligodendrocyte marker） was performed to detect the differentiation commitment of affected neural stem cells after 6 days. The data showed that Pb2~ inhibited not only the viability and proliferation of rat hippocampal neural stem cells, but also their neuronal and oligodendrocyte differentiation in vitro. Moreover, increased activity of astrocyte differentiation of hippocampal neural stem cells from both newborn and adult rats was observed after exposure to high concentration of lead ion in vitro. These findings suggest that hippocampal neural stem cells of newborn rats were more sensitive than those from adult rats to Pb2＋cytotoxicity.
Lead ion （Pb2＋） has been proven to be a neurotoxin due to its neurotoxicity on mammalian nervous system, especially for the developing brains of juveniles. However, many reported studies involved the negative effects of Pb2＋ on adult neural cells of humans or other mammals, only few of which have examined the effects of Pb2＋ on neural stem cells. The purpose of this study was to reveal the biological effects of Pb2＋from lead acetate [Pb （0H30OO）2] on viability, proliferation and differentiation of neural stem cells derived from the hippocampus of newborn rats aged 7 days and adult rats aged 90 days, respectively. This study was carried out in three parts. In the first part, 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide assay （MTT viability assay） was used to detect the effects of Pb2＋ on the cell viability of passage 2 hippocampal neural stem cells after 48-hour exposure to 0-200 pM Pb2＋. In the second part, 10 pM bromodeoxyuridine was added into the culture medium of passage 2 hippocampal neural stem cells after 48-hour exposure to 0- 200 pM Pb2＋, followed by immunocytochemical staining with anti-bromodeoxyuridine to demonstrate the effects of Pb2＋ on cell proliferation. In the last part, passage 2 hippocampal neural stem cells were allowed to grow in the differentiation medium with 0-200 pM Pb2＋. Immunocytochemical staining with anti-microtubule-associated protein 2 （a neuron marker）, anti-glial fibrillary acidic protein （an astrocyte marker）, and anti-RIP （an oligodendrocyte marker） was performed to detect the differentiation commitment of affected neural stem cells after 6 days. The data showed that Pb2~ inhibited not only the viability and proliferation of rat hippocampal neural stem cells, but also their neuronal and oligodendrocyte differentiation in vitro. Moreover, increased activity of astrocyte differentiation of hippocampal neural stem cells from both newborn and adult rats was observed after exposure to high concentration of lead ion in vitro. These findings suggest that hippocampal neural stem cells of newborn rats were more sensitive than those from adult rats to Pb2＋cytotoxicity.
基金
supported by a grant from the University of Hong Kong, China
