Keywords: 
• prenatal /
• lactational /
• cross-feeding /
• PFOS /
• learning and memory abilities

Abstract: The purpose of the present study is to investigate the developmental neurotoxicity of PFOS, and to identify the sensitive period of exposure. Morris Water Maze (MWM) and histopathological examinations were used to evaluate the effects of prenatal and lactational exposure to PFOS on the development of offspring. Learning and memory abilities of pups were assessed, as well as the grip of pups and pathological changes of hippocampus. The results showed that PFOS caused growth retardation, prolongation of eye opening, and reducing in birth weight of pups compared with the control group. Body weights of pups with prenatal exposure were lower than that with lactational exposure under the same concentrations of PFOS exposure. No significant change was observed in grip after PFOS exposure. MWM results showed that the escape latency of TT15 (exposed to 15 mg·L^-1 PFOS in both prenatal and lactational period) and TC15 (exposed to 15 mg·L^-1 PFOS in prenatal period) exposure groups was significantly longer than the control group. In addition, escape latency of TC15 exposure group was significantly longer than CT15 (exposed to 15 mg·L^-1 PFOS in lactational period) exposure group. Probe trial experiment suggested that the time spent in the target quadrant of pups from TT15 group was significantly shorter than those from control group, and there was no significant change in other groups. Histopathology observation indicated reduced cells and apoptosis in hippocampus. PFOS caused the developmental delay of offspring, as well as decline of learning and memory abilities, and prenatal period might be the critical stage to PFOS exposure.