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AIM To study the expression of brain-derived neurotrophic factor (BDNF) in lymphocytes modified by BDNF gene and its effect on the proliferation and the H 2O 2-induced apoptosis of PC12 cells for the transfer of ex vivo therapeutic gene into central nervous system (CNS) tissue with atraumatic means. METHODS Recombined BDNF cDNA plasmid was transfected by LipofectAMINE into the packing cell line PA317 and G418-resistant clones with highest titer was selected. Rat lymphocytes were infected repeatedly with virus supernatant. The expression of BDNF in rat lymphocytes was assayed by FCM and immunohistochemistry. The proliferation of PC12 cells was evaluated by MTT assay. H 2O 2-induced apoptosis of PC12 cells was determined by PI stain flow cytometry. RESULTS BDNF expressed in rat lymphocytes genetically modified and the concentration of BDNF in the conditioned medium of engineered lymphocytes had a linear correlation with the proliferation of the PC12 cells. The supernatant of lymphocytes modified by BDNF gene decreased the apoptosis of PC12 cells induced by H 2O 2. CONCLUSION Rat lymphocytes genetically modified can express and secret active BDNF in vitro.
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AIM To study the adaptive cytoprotection of H 2O 2 preconditioning against oxidative stress damage in PC12 cell and the relationships between brain derived neurotrophic factor (BDNF) and the adaptive cytoprotection of H 2O 2 preconditioning. METHODS The viability of PC12 cells was evaluated by MTT assay. Apoptosis was detected by PI stain flow cytometer. Expression of BDNF was analyzed by immuo flow cytometer. RESULTS After H 2O 2 preconditioning, the survival of PC12 cells exposure to H 2O 2 (20～60 ?mol?L -1 ) was increased and the apoptosis of PC12 cells induced by H 2O 2 (20 or 30 ?mol?L -1 ) was inhibited and the expression of BDNF in PC12 cells was enhanced. CONCLUSION H 2O 2 preconditioning is protective against the damage of PC12 cells induced by H 2O 2 and its mechanisms may involve up modulation of the expression of BDNF.
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Objective To investigate the effect of 50Hz magnetic field on the monoamine neurotransmitters contents in the hippocampus of rats. Methods 32 male SD rats were divided into 4 groups, exposed to 50 Hz magnetic field at the density of 0, 0.1, 1.2, and 1.6 mT, 2 h a day for a certain time. The contents of NE, E, DA and 5-HT were measured by HPLC. Results The contents of NE, DA and 5-HT in hippocampus were increased when the young rats were exposed to 1.2 and 1.6 mT for 10 days, the changes of monoamine neurotransmitters in 0.1 mT exposed group was not significant. The increase in monoamine neurotransmitters was disappeared when the 1.6 mT exposed group stop being exposed to the magnetic field for 30 days, while the monoamine neurotransmitters contents were decreased when the young rats were continuously exposed to 1.2 mT for 90 days. The contents of NE, DA and 5-HT, except E, in the old rats were decreased significantly when exposed to 0.1 mT intensity for 8 months. Conclusion Magnetic field exposure may affect the monoamine neurotransmitters content in the hippocampus, which may be responsible for the changes of learning and memory of rats induced by 50 Hz magnetic field exposure.
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Objective To study the effects of short-term and long-term exposure to extremely low frequency electromagnetic field(ELFEMF)on Morris learning and memory among rats. Methods Both younger(2-3 months old)and adult(18 months old)male SD rats were exposed to 50 Hz uniform ELFEMF with continuously adjusted intensities(0.1,1.2,1.6 mT) developed by Helmholtz coil pair for 10 days to 8 months. The levels of escape latency and the crossing annulus coefficients reflecting the behavioral changes in place navigation ability and spatial probe ability were examined by Morris water maze after exposure to ELFEMF among rats. Results The escape latency was shortened and the crossing annulus coefficients were increased compared with those of control group when the younger rats were exposed to 0.1,1.2 and 1.6 mT ELFEMF for 10 days respectively,and only revealed significant differences in 1.2 and 1.6 mT ELFEMF exposure groups compared with those of control group. In the younger rats of 1.6 mT ELFEMF exposure group with 10-day exposure ,their escape latencies were prolonged and the crossing annulus coefficients were decreased gradually and showed no significant differences compared with those of control group after the 30-day blank exposure period without ELFEMF.The younger rats of 1.2 mT ELFEMF exposure group showed significantly longer escape latency and lower crossing annulus coefficient compared those of control group after continuous 90-day exposure to 1.2 mT ELFEMF. The escape latency of adult rats in 0.1 mT ELFEMF exposure group showed no significant difference after 10-day exposure,was prolonged after 4-month exposure,and was significantly prolonged further more after 8-month exposure. Conclusion The learning and memory ability could be promoted by short-term ELFEMF exposure and impaired by long-term ELFEMF exposure for the young rats,and could be obviously inhibited by long-term ELFEMF exposure for the adult rats.