title: Total antioxidant status of zinc, manganese, copper and selenium levels in rats exposed to premium motor spirit fumes.
abstract: BACKGROUND
  Frequent exposure to premium motor spirit (PMS) is common and could be a risk factor for liver dysfunction in those occupationally exposed. A possible association between PMS fumes and plasma total antioxidant status as well as plasma levels of zinc, manganese, copper and selenium using a rodent model could provide new insights into the pathology of the liver where cellular dysfunction is an established risk factor.
  
  
  OBJECTIVE
  This study aimed to determine the total antioxidant status and plasma levels of zinc, copper, selenium and manganese in those occupationally exposed using rodent model.
  
  
  METHODS
  25 albino Wistar rats of both sexes were used for this study. The animals were divided into five groups of five rats in each group. Group 1 rats were not exposed to PMS fumes (control group), group 2 rats were exposed for 1 hour daily, group 3 for 3 hours daily, group 4 for 5 hours daily and group 5 for 7 hours daily. The experiment lasted for a period of 4 weeks. Blood samples obtained from all the groups after 4 weeks of exposure were used for the determination of plasma total antioxidant status as well as plasma levels of zinc, manganese, copper and selenium.
  
  
  RESULTS
  Results showed significant increases in means of plasma copper (69.70±0.99 for test and 69.20±1.02 for control, P < 0.05) and selenium (72.70±1.58 for test and 68.20±0.86 for control, P < 0.05) in the exposed rats when respective mean values were compared with those of corresponding controls. Mean body weight index (BWI) and percentage weight increase (PWI) were significantly lower (P < 0.05) in exposed rats when compared with the unexposed group. The mean plasma levels of zinc (137.40±4.06 for test and 147.80±2.52 for control) and manganese (65.75±1.02 for test and 70.00±0.71 for control) showed significant decrease (P < 0.05) when compared with control. Plasma level of total antioxidant status (TAS) did not differ significantly in exposed rats when compared with the control group.
  
  
  CONCLUSIONS
  This study showed that frequent exposure to PMS fumes may lead to increase plasma levels of copper and selenium probably due to liver dysfunction and decrease in plasma levels of zinc and manganese probably as a result of interference in their metabolic pathway of the exposed groups.
authors.affiliation: Department of Chemical Pathology, University of Benin Teaching Hospital, Benin City, Edo State, Nigeria.
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Okuonghae
authors.forename: Lewis O
authors.initials: LO
authors.lastname: Aberare
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Mukoro
authors.forename: Favour
authors.initials: F
authors.lastname: Osazuwa
authors.forename: John O
authors.initials: JO
authors.lastname: Dirisu
authors.forename: Johanna
authors.initials: J
authors.lastname: Ogbuzulu
authors.forename: Richard
authors.initials: R
authors.lastname: Omoregie
authors.forename: Moses
authors.initials: M
authors.lastname: Igbinuwen