Age-related changes in antioxidant enzyme activities in the brain and liver of BN/Bi rats: Striking differences from those in F344 rats emphasize the need for "public observations" for generating a general theory of aging

Abstract

Objective: Age-related changes in endogenous antioxidant enzyme activities have been widely discussed in relation to mechanisms of organismic aging. However, some discrepancies in this regard can be seen in the published work. The present study aimed to clarify past discrepancies using BN/Bi rats in which no study has been reported in the past. Methods: Antioxidant enzyme activities such as superoxide dismutase (SOD) and catalase (CAT) were compared in several brain regions and the liver between young (8–9 months) and old (27–29 months) BN/BiRijHsd rats of both sexes. Results: CAT activities in brain regions were quite comparable between young and old rats of both sexes. SOD activity changes with age also were not remarkable, with the exception of significantly lower Mn-SOD activities in substantia nigra and hippocampus of old male rats and significantly higher activities of Cu/Zn-SOD in substantia nigra of old female rats in comparison with respective values in young rats. CAT activities in the liver tended to be lower in old male rats, while in females the opposite was observed. SOD activities in the liver stayed essentially unchanged with age in males, while in females total as well as Cu/Zn-SOD activities were more than twofold higher in old animals. Conclusion: These data coupled with previously reported results, indicate that no generalization can be made in terms of age-related changes in antioxidant enzyme activities. These differences emphasize the need of “public observations” in any attempt to generate a theory for mechanisms of aging based on antioxidant enzyme activity changes with age.