| Lead (Pb) exists widely in the environment. It has multi-system and multi-organ toxicity. Children are sensitive to it, and their nervous system development can be interrupted by low-level long-term exposure. Oxidative stress is one of the important mechanisms of lead toxicity. The antioxidant effect of resveratrol (RES) might reduce the damage caused by the reactive oxygen species reaction to the brain tissue.ObjectivesThe goal of present study is to investigate the protective effect of RES on lead exposure young mice. The parameters observed included the mouse blood and hippocampal lead level, serum and hippocampal superoxide dismutase (SOD), malondialdehyde (MDA) levels, hippocampal NGF mRNA expression, and the mouse spatial learning memory performance.MethodsFifty Kunming mice, weigted18--22g, were randomly divided into five groups: one was control group (control, C), fed with distilled water, and the others were fed with lead containing water (lead concentration was1.0g/L), of which, one was lead exposure only group (Pb), the rests were RES interferning groups, named as low (L), middle (M), and high (H) dose groups, the drink water contained200mg/L,400mg/L, and600mg/L of RES respectively. The mice were allowed freely to access the lab chow diet and assigned drinking water. The animals were weighed weekly. After eight-weeks feeding, Morris water maze (MWM) test was employed for four continuous days to evaluate the spatial learning memory ability in the mice. Then, under anaesthesia condition, the mice blood samples were drawn from orbital sinus. Their brain tissues were dissected and the hippocampus was isolated. The lead levels in blood and hippocampus were analyzed by graphite furnace atomic absorption spectrometry. Serum and hippocampal SOD activity and MDA level were measured by SOD and MDA kit. The expression level of hippocampal NGF mKNA was quantified by RT-PCR method.Results From6th weeks of feeding, mouse body weight showed significantly different among some groups. The Pb group was lower than the C group (P<0.05), while the H group was higher than the Pb group (P<0.05) at six weeks. The Pb and L groups were markedly lower than the C group (P<0.05), while the H group was significantly higher than the Pb group(P<0.05) at seven weeks. The Pb, L, and M groups were lower than the C group (P<0.01), while the H groupwas higher than the Pb group (P<0.05).MWM test showed that the escape latency was significantly increased in Pb and L groups (P<0.01), while the M and H groups showed shorter escape latency (P<0.01), the effect was dose dependent.The blood and hippocampal lead concentrations were significantly higher in Pb, L, M and H groups than that in C group (P<0.01). The blood lead level was lower in H group than that in Pb group (P<0.01). The hippocampal lead levels were lower in M and H groups than that in Pb groups (P<0.01), the L group hippocampal lead level was also lower than the Pb group (P<0.05). The serum and hippocampal SOD activity levels were significantly decreased in Pb and the three RES interfering groups and MDA levels were increased compared with the C group (P<0.05). The SOD activity levels in M and H groups were higher, but MDA levels were lower than that in the Pb group (P<0.05). The expression levels of hippocampal NGF mRNA in Pb and three RES groups were significantly decreased than the C group (P<0.01), while the expression levels were higher in M and H groups than that in Pb group (P<0.01).ConclusionChronic lead exposure could elevate blood and hippocampal lead level, influence body weight gain, and cause defect of learning and memory in mice. The lead exposure could cause oxidative stress, e.g. decrease the SOD activity level and increase the content of MDA in mice serum and hippocampus, and decrease hippocampal NGF mRNA expression. RES could reverse above impacts and improve body growth and brain function in mice.RES shows protective effect on central nervous system through anti-oxidation mechanism, the effect is dose dependent. |
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