Neurotoxic Effects Of Perfluorooctanesulfonate (PFOS) On Rats: An Experimental Study

PFOS ( perfluorooctanesulfonate) and related N-alkyl perfluorooctanesul-fonamido compounds have been manufactured by 3M Company from perfluo-rooctanesulfonyl fluoride since 1948. This class of compounds has been utilized in protective coatings for carpets and apparel, paper coatings approved for food contact, insecticide formulations, and surfactants et al. Investigation has shown that PFOS has distributed throughout the world. PFOS has the properties of good absorption, chemical stability toward degradation and poor elimination. In previous toxicity studies PFOS has shown multisystemic toxicity including decreased body weight, decreased serum cholesterol, decreased triglycerides, hepatocellu-lar hypertrophy and vacuolation, increased liver-to-body weight ratios, death and reproductive toxicity. PFOS can also lead to Convulsion of primates and lag the conditoned reflex formation of Rodents. This study was conducted to determine the histopathological changes, glutamate and Bcl-2 expression of the rats brain after exposed to PFOS.Materials and Methods1. Animal grouping, administration and sample collection 1. 1 Animal grouping: 20 healthy adult Wistar rats ( male, body weight 180 + 10g) were randomly assigned into 4 groups after allowing free access to food and tap water for 7 days.1.2 Administration; Rats were decapitated respectively at the other day after exposed to PFOS ( doses 50mg/kg, 100mg/kg 200mg/kg, control 2% Tween80) once orally.1. 3 Sample collection; At the 24h after the administration of PFOS, blood samples were collected after the rats were decapitated rapidly on ice plate then perfused from the left ventricles to with 4% polymerisatum, at last the. brains were removed to a bottle filled with formaldehyde solution for fixation.2. Observation and determination2. 1 The pathological study was performed with optical and electronic microscopes.2. 2 The percentage of positive area and integral optical density of Gluta-mate reactive cells in rats CNS were studied by immunohistochemical method (SABC).2. 3 The percentage of positive area and integral optical density of Bcl-2 im-munoreactive cells in rats CNS were studied by immunohistochemical method (SABC).3. Reagent and ApparatusPerfluorooctanesulfonate, 25% glutaraldehyde, Glu polyclonal antibody, Bcl-2 polyclonal antibody, SABC immunohistochemistry Test Kit, Leitz1512 microtome, BX60F/PM30-3 photomicroscop system.4. Data statistical analysisAnalysis of variance were performed with SPSS packages.Results1. the histopathological changesIschemia was the mainly change in cerebrum cortex, Hippocampus pyramidal cell and cereBcllum Purkinje cell with optical microscopes.2. The expression changes of glutamateThe percentage of positive area and integral optical density of glutamate im-munoreactive cell in cerebral cortex, hippocampus and cereBcllum increased significantly ( p <0.01) in the rats exposed to Perfluorooctanesulfonate with a dose-effect relationship.3. The expression changes of Bcl-2The percentage of positive area and integral optical density of Bcl-2 immu-noreactive cell in cerebral cortex, hippocampus and cereBcllum increased significantly (p<0.01) in the rats exposed to Perfluorooctanesulfonate with a dose-effect relationship.DiscussionPFOS (perfluorooctanesulfonate) have been manufactured since 1948 and rapidly spreaded throughout the world. Until now both polar bear and penguin has been examined to have some concentration of PFOS in their bodies. Research has shown that PFOS has the properties of good absorption, chemical stability toward degradation, poor elimination and multisystemic toxicity. There is an increasing concern of PFOS contamination by environmentalists from many countries.This study was conducted to determine the histopathological changes, glutamate and Bcl-2 expression of the rats brain after exposed to PFOS. Result shows : 1. Ischemia was the mainly change in cerebrum cortex, Hippocampus pyramidal cell and cereBcllum Purkinje cell with optical...