【Objective】 To explore the possible mechanism of learning and memory impairment in filial rats with lead exposure of mother pregnant rats by observing the ultrastructural pathologic changes of hippocampal neurons and organelles, and the features of synaptic morphological parameters. 【Methods】 Female pregnant Spraque-Dawley (SD) rats were divided into high dose lead exposure group(HG) and low dose lead exposure group(LG) by drinking 0.1% or 0.2% lead acetate dissolved by three distilled water,the normal control group(NG) pregnant rats drank three distilled water.36 days after birth, transmission electron microscope were used to examine the ultrastructural pathologic changes of neurons and organelles,and the features of synaptic morphological parameters of hippocampal CA1 area in 9~12 male filial rats from HG,LG or NG group. 【Results】 Severe ultrastructural pathologic changes were found in hippocampal CA1 area of filial rats with lead exposure of mother pregnant rats.The changes of neuronal degeneration and necrosis,mitochondria swelling,polyribosomes disaggregation from endoplasmic reticulum,and golgiosomes dilation in lead exposure group were more significantly severe than those of the control group(P<0.05 or <0.01).Compared with the control groups, lead exposure group showed significant decreases of postsynaptic density thickness,synaptic active zone length,and synaptic interface curvature,as well as significant increases of synaptic cleft (all P<0.01) .In addition, lead exposure group showed no significant differences in synaptic numeric density and synaptic surface density as compared with the control groups. 【Conclusions】 Lead exposure of pregnant rat could result in severe ultrastructural pathologic chandes of neurons and organells,as well as the significant synaptic plasticity in hippocampal areas of filial rats.The possible mechanism of learning and memory impairment in filial rats with lead exposure of mother pregnant rats is also relative to these pathologic changes.
Key words
lead exposure /
ultrastructure /
hippocampus /
synapse /
rat
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