Effects of nonylphenol exposure via placenta on spatial learning and memory capacity and uitrastructural changes in hippocampus of offspring in rat

Objective To explore the influence of nonylphenol(NP) on the filial generation rats spatial learning and memory capacity which were exposed to the parent rat during its pregnancy. Methods At the first day of the pregnancy, the rats were divided into four groups, which were orally administered with NP at doses of 0,50, 100 and 200 mg/kg,respectively, on gestational days 9～15. Cognitive function was tested by Morris water maze and step-down test. The ultrastructure of hippocampus tissues were observed by electronic microscope.Result The escape latency extended ((61.14±5.92) s) and erroring time increased ((4.57±1.13)times) in Morris water maze, and step down latency extended ((37.5±6.3)s), step through latency shortened((97.8±11.0)s) and erroring time increased ((3.0±1.4) times) in step down test in the N P 200 mg/kg treated groups (P<0 05). The correspond indexes were separately (35.85±4. 29) s, (2.57±0.97) time, (27.1±3.8) s,(172.0±89.2)s and(0.9±0.7)time in control group. Compared to the control group, there were significant differences in the results of the water maze test and step-down test between NP 200 mg/kg and the control group (P <005). The changes of the uhrastructure were found among the hippocampus neurons of NP 200 mg/kg group that characterized with chromatin condensed,clumped in circa-nuclei and mitochondrial tumefaction and vacuolization.Conclusion Exposures to NP during gestation might decreased abilities of spatial learning and memory capacity on F1 rats significantly. Key words: Nonylphenol;  Offspring;  teaming and memory;  Hippocampus ultrastructure