ABSTRACT
OBJECTIVE To investigate the delayed cytotoxicity effect of chlorpyrifos (CPF) with?drawal on primary hippocampal neurons. METHODS Hippocampal neurons were prepared from SD rat fetuses on the 17th day of gestation. Seven days after culture,neurons were exposed to CPF 10 and 30 μmol · L-1,respectively,for 72 h or for 48 h followed by CPF withdrawal for 24 h. CCK-8 kit and neuronal nuclei(NeuN), 5-bromodeoxyuridine(BrdU) and β Ⅲ tubulin immunofluorescence expression methods were used to evaluate the cell viability. RESULTS Compared with normal control, no significant cytotoxicity was found after CPF 72 h continuous exposure. However,CPF 48 h expo?sure followed by CPF withdrawal for 24 h induced evident cytotoxicity. The amount of BrdU positive and β Ⅲ tubulin positive hippocampal neurons were both decreased significantly(P<0.05),and cell survival and viability reduced after CPF withdrawal. CONCLUSION CPF exposure withdrawal can induce more seriously delayed cytotoxicity than continuous exposure in rat primary hippocampal neurons.
ABSTRACT
AIM: To investigate the effects of metallothionein (MT) induced by zinc on doxorubicin (DOX)-treated mice and to explore the potential mechanisms. METHODS: Male C57BL/6J mice were divided randomly into 4 groups (n = 6) following control, DOX, Zn and Zn plus DOX. Mice were pretreated with eikg-1, ip) or equal volume of saline, and were killed on d 4 after the last injection. Serum and hearts were collected for examination. RESULTS: Zinc pretreatment elevated cardiac MT levels significantly while other antioxidants in heart including glutathione (GSH), glutathione peroxidase (GSHpx) , superoxide dismutase (SOD), and catalase (CAT) were not altered. Severe oxidative injury occurred in the mice treated with DOX as myocardial lipid peroxidation and morphological changes manifested by myocardial fibers swelling and vacuolization and nuclear condensation or dissolution, with increased activities of serum creatine kinase and lactate dehydrogenase and depletion of GSH, GSHpx, and SOD while CAT activity was increased in compensation. However, pre-induction of MT with zinc attenuated all of these toxic changes significantly. Furthermore, DOX induced elevation of hydrogen peroxide in heart tissues was greatly inhibited by zinc pretreatment. CONCLUSION: Preinduction of MT by zinc protects the heart from DOX-induced cardiotoxicity, and this effect is possibly correlated with the property of MT on scavenging free radicals in vivo.