Objective    To explore the effects of maternal exposure to dibutyl phthalate (DBP)

an environmental estrogen on the proliferation and differentiation of neural stem cells (NSCs) in the neural tube of neonatal rats.     Methods    A total of 40 male and 40 female SD rates at age of 4 to 5 months

were matched

and the morning when vaginal plugs were found was designated as E0. Then the 40 pregnant rats were randomly divided into 4 groups

3 DBP exposure groups (25

75

and 225 mg/kg) and control group. DBP at corresponding doses were dissolved in corn oil

and administrated by intragastrically injection once per day from E0 till delivery

while those of control group were given corn oil. Brain tissue of newborn rats was collected for primary culture of NSCs. Then the cell colony formation was counted to detect the NSCs proliferation. Then 10% fetal bovine serum (FBS) was added into the culture medium to induce the NSCS to differentiate. Neu-N and GFAP immunofluorescence stainings were used to detect neurons and astrocytes

and their morphological changes were observed.     Results    The proliferation of NSCs was decreased significantly after DBP administration. Compared with the control group [(40.53±4.65)%]

the colony formation rate of middle- and high-dose DBP exposure groups was significantly reduced and in a dose-dependent manner [(30.96±3.80)%

(15.35±5.29)%

(6.58±1.43)%

P0.01]. The diameter of the formed colony in high-dose DBP exposure group was significantly smaller than in control group. DBP induced more NSCs to differentiate to astrocytes in high-dose group [(36.8±3.5)%] than in control group [(30.8±2.4)%

P0.01] Morphological changes were more obvious in the differentiated neurons and astrocytes with the increasing dose of DBP. DBP also caused obvious gradually shortened and thickened processes

especially in the high dose group.     Conclusion    The results suggest that DBP exert obvious effect on the proliferation and differentiations of NSCs

and thus affects the development of neural system.