Study On The Effects Of Arsenic Exposure On The NF-?B-PKA-CREB Signaling Pathway In The Hippocampus Of Offsping Mice At Different Developmental Stages

ObjectiveTo investigate the impairment mechanism of learning and memory ability induced by arsenic exposure through studying the effects of arsenic on the levels of nuclear transcription factor-?B(NF-?B),protein kinase(PKA)and cAMP response element-binding protei(CREB)in the hippocampus of offspring mice at different developmental stages.To provide further experimental reference data for further clarifying the neurotoxic mechanism of arsenic.MethodsTo set up the model of offspring mice exposed to arsenic at different developmental stages.From the first day after conception,the mice were exposed to arsenic(NaAsO2)by free drinking water.The offspring mice exposed to arsenic through maternal blood circulation and milk before weaning,and exposed to arsenic through drinking water after weaning.The concentrations of arsenite were 0,15,30 and 60 mg/L.Morris water maze was used to test the effects of arsenic exposure on learning and memory of offspring mice of postnatal day(PND)40.The weights of the pups were recorded on PND 10,20 and 40,then the brain tissue was removed and the hippocampus was isolated.The nuclear translocation level of NF-?B in the hippocampus of the pups was determined by electrophoretic mobility shift assay(EMSA).The expression of NF-?B P65 mRNA in the hippocampus of pups was detected by Real time RT-PCR.The expression levels of p-NF-?B P65,PKA and p-CREB in the hippocampus of pups were detected by Western blot.ResultsThere was no significant difference of body weights of PND10 mice among groups(P>0.05).The body weights of PND 20 mice in 60 mg/L NaAsO2 group were significantly lower than those in control;the body weights of PND 40 mice in 30 and 60 mg/L NaAsO2 groups were significantly lower than those in control;the body weights of PND 40 mice in 60 mg/L NaAsO2 group were significantly lower than those in 15 mg/L NaAsO2 group(P<0.05).There was no significant difference of the whole brain coefficient of PND10 mice among groups(P>0.05).The whole brain coefficients of PND 20 and 40 pups in 60 mg/L NaAsO2 group were significantly higher than those in control;the whole brain coefficients of PND 40 pups in 60 mg/L NaAsO2 group were significantly higher than those in 15 mg/L NaAsO2 group(P<0.05).Morris water maze test results showed that there was no significant difference of the escape latency of pups among groups in the training on the first three days(P>0.05),on the fourth and fifth days of training,the escape latency in NaAsO2 exposed groups was significantly longer than that in control(P<0.05).In the probe trail,the time spent in target quadrant(platform existed previously)in 30 and 60 mg/L NaAsO2 exposed groups was significantly shorter than that in control(P<0.05).The results of EMSA showed that there was no significant difference of the nuclear translocation levels of NF-?B in the hippocampus of PND 10 pups among groups(P>0.05).The nuclear translocation levels of NF-?B in the hippocampus of PND 20 mice in 60 mg/L NaAsO2 group was significantly lower than those in control and 15 mg/L NaAsO2 group(P<0.05).The nuclear translocation levels of NF-?B in the hippocampus of PND 40 mice in 30 and 60 mg/L NaAsO2 groups were significantly lower than those in control and 15 mg/L NaAsO2 group(P<0.05).Real-time RT-PCR results showed that there was no significant difference of NF-?B P65 mRNA levels in the hippocampus of PND 10 and 20 mice among groups(P>0.05),mRNA levels of NF-?B P65 in the hippocampus of PND 40 mice in 30 and 60 mg/L NaAsO2 groups were significantly lower than those in control(P<0.05).Western blot analysis showed that there was no significant difference of the expression of p-NF-KB P65 protein in the hippocampus of PND 10 mice among groups(P>0.05);the expression levels of p-NFB P65 protein in the hippocampus of PND 20 pups in 60 mg/L NaAsO2 group were significantly lower than those in control,and which of PND 40 mice in NaAsO2 exposed groups were significantly lower than those in control(P<0.05).The expression levels of PKA protein in the hippocampus of PND 10 mice in NaAsO2 exposed groups were significantly lower than those in control(P<0.05);the expression levels of PKA protein in the hippocampus of mice at different developmental stages in 30 and 60 mg/L NaAsO2 groups were significantly lower than those in control and 15 mg/L NaAsO2 group(P<0.05),which in the hippocampus of PND 40 mice in 60 mg/L NaAsO2 group were significantly lower than those in 30 mg/L NaAsO2 group(P<0.05).There was no significant difference in the expression level of p-CREB protein in the hippocampus of PND 10 mice among groups(P>0.05);the expression levels of p-CREB protein in the hippocampus of PND 20 and PND 40 mice in 30 and 60 mg/L NaAsO2 groups were significantly lower than those in control(P<0.05).Conclusions1.Arsenic exposure can reduce the ability of learning and memory of offspring mice;2.Arsenic exposure can reduce the nuclear translocation and expression levels of NF-?B in the hippocampus of offspring mice,which may affect the ability of learning and memory;3?Arsenic exposure can decrease the protein levels of PKA and p-CREB in the hippocampus of offspring mice.