| ObjectivePerfluorooctane sulfonate (PFOS,CFSO) is a degradation product of Perfluorinate compounds(PFCs) that are widely used in the manufacture of plastic, electronics, textile, and construction material in the apparel, leather, and upholstery industries. The PFOS is shown to be globally distributed, environmentally persistent and bioaccumulative. The environmental survey show that each body of water inside the scope and in the serum of all of the wildlife animals include Arctic has shown widespread distribution of PFOS. The census of population investigates that PFOS has been detected in the serum of all countries inside the global scope.The toxicological researches confirm that PFOS has the development toxicity, the immunity toxicity, the reproductive toxicity and the potential cancer-causing to experimental animals. But we still have seldom reports about the neurotoxicity cause by PFOS. The aim of our present study is to evaluate the effects of PFOS on [Ca] in order to examine the mechanism how PFOS effects the central nervous system. And our research also proposes to take expects to the recommendations of the hazard assessment.Material and method1(?) Animals and treatment(1) Materials and dose preparationPFOS was dissolved in 2% Tween-80 as designed dose, which was calculated by the Horn method via alimentary canal.(2) Animals and treatment 50 male rats were randomly divided by weight into five groups of 10/sex/group after a 7-day acclimation period, which were weighed 180-220g. Male rats were set to maintain temperature, humidity, and a 12-h light: 12-h dark cycle. The treated group's doses were 2, 8, 32, 128 mg(?)kg(feed).The feed and water were provided adlibiturn with all groups throughout the course of the study. Consecutive breed for 60d.The rat is anaesthetized by 0．4 %(w/v) soluble pentobarbitone. Take the brain and stripping hippocampus, and then conserve the serum and the remaining brains into cryopreservation at-80(?).2(?) Methods(1) The weight and the food consumption;(2) The record of hypersound stimulus;(3) The concentrations of PFOS in serum and brain-High performance liquid chromatography/Mass spectrography (HPLC/MS);(4) Intracellular free calcium concentration in hippocampus-Fura-2/AM fluorescence probe methods;(5) Histopathological change in pallium,hippocampus and cerebell-Nissl's staining.3(?) StatisticsThe data sign to mean with the mean (?) SE. Changes in every array were analyzed by analysis of variance (ANOVA) followed by Fisher's least significant difference (LSD) after those have been showed as the normal distribution by the SPSS 13．0．If the analysis of normal distribution was not appropriate, the Kruskal-Wallis test was used identify the statistical significance of the individual groups.Results1(?) The weight and the food consumptionThe body weight gain increment was reduced by the increase dose of PFOS in same treated days. The weight in group treated with 32 mg(?)kg(feed)and 128 mg(?)kg(feed)were significantly lower than the corresponding control group and the 8 mg(?)kg(feed) treated group (p<0．01) . After the first period (0-30d), statistically significant reductions in absolute feed consumption values were observed in the 128 mg(?)kg(feed), while there was no significant statistically among all groups in the first period.2(?) The record of hypersound stimulusThere showed no statistically significant between the treated groups and the control group (p>0．05) .3(?) The concentrations of PFOS in serum and brainPFOS concentration in serum and brain in 8 mg(?)kg(feed) and higher dose treated groups were significantly higher than that in the control group (p<0．01) ,and there was a significant positive correlation between 8 mg(?)kg(feed) and higher dose treated groups in serum and brain (r=0．944, p<0．01) . The concentration of PFOS in serum in 2 mg(?)kg(feed) group was significantly higher than that in the control group (p<0．01) . There were no significantly statistically in the concentration of PFOS in serum and brain between the 8 mg(?)kg(feed) group and the 2 mg(?)kg(feed) group.4(?) Intracellular free calcium concentration in hippocampusThe Intracellular free calcium concentration in hippocampus in 2,8,32,128mg(?)kg(feed) PFOS treated group were(222．27(?)9．67) nmol(?)L, (244．29(?)9．07) nmol(?)L,(381．69(?)9．61) nmol(?)Land(528．27(?)15．51) nmol(?)L respectively, and there were significant difference between the experimental groups and the corresponding control group [(141．30(?)2．70) nmol(?)L](P<0．01) .There was a significant relationship between intracellular([Ca]i) and administrated doses of PFOS(r=0．929, P<0．05) .There was a positive correlation between [Ca] in hippocampus and PFOS concentration in brain(r=0．801,p<0．01) ,with the positive correlation between [Ca] in hippocampus and PFOS concentration in serum(r=0．955,p<0．01) ,and the positive correlation between [Ca] in serum and PFOS concentration in brain(r=0．811, p<0．01) 5(?) Histopathological change in pallium,hippocampus and cerebellAll cells have the equal kytoplasm and cyclo-nucelus in all groups ,which were the pyramidal cell in the external granular layer and the pyramidal layer in cerebral cortex ,the pyramidal cell in M stage in CA1 area in hippocampus and the Purkinji cell in cerebell. The Nissl's body were purple, and some entoblast showed obviously. There were no pathochange in Nissl's body among all groups.Conclusion1(?) PFOS could reduce the body weight gain increment and the absolute feedconsumption values.2(?) PFOS could increase the concentration of PFOS in serum and brain.3(?) PFOS could increase the intracellular free calcium concentration in hippocampus.4(?) PFOS could not cause the pathochange of cells in cortex, hippocampus and cerebell. |
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