Effect of lead exposure on protein expression of mGluR5 in hippocampus and learning memory in rats

ObjectiveTo observe effects of low level lead exposure during pregnant on expression of metabotropic glutamate receptor 5(mGluR5)in hippocampus and learning and memory in rats.MethodsThirty pregnant rats were randomly divided into 3 groups,and the rats were fed with doubly distilled water in control group and 0.05%,0.2%lead acetate(PbAc)solution in treatment groups via drinking water during pregnancy and lactation.After weaning,the offspring rats were directly fed with drinking water as their dams.Western blot was used to detect the protein expression of mGluR5 in hippocampus of offspring rats at postnatal 7,14,21,and 28 days,respectively.The contents of lead in blood and hippocampus were determined with atomic absorption spectrophotometer at postnatal 28 days.Morris water maze test was used to observe the change of learning and memory at postnatal 56 days.ResultsLow level lead exposure during pregnancy resulted in the decreases of spatial positioning navigation in the offspring rats.The time of searching for the platform in the offsprings of the rats in 0.05%and 0.2%PbAc groups were 40.13±9.20,32.82±6.45,26.83±7.12 and 61.50±13.84,54.51±9.65,19.81±4.92 seconds at 3,5,and 7 day of training,compared to those of the control group,which exhibited a significant extension(P<0.05).The expression of mGluR5 in hippocampus of 0.05% and 0.2% PbAc group at postnatal 7,14,21,and 28 days were 0.607±0.027,0.845±0.010,0.713±0.004,and 0.587±0.011 and 0.540±0.025,0.573±0.014,0.551±0.014 and,0.492±0.017,with a decreased tendency compared to those of the control group(P<0.05).ConclusionChronic lead exposure results in decrease of spatial learning and memory and its effect may relate to the decline of expression of mGluR5 in hippocampus in rats.