Protective effect of 17â-estradiol on oxidativestress and liver dysfunction in aged male rats

ABSTRACT

In aging liver oxidative stress increases due to the decrease in antioxidant bio-moleculessuch as estrogens which can be modified by hormonal replacement therapy(HRT). With this in mind, we hypothesized that age-related decline in steroidogenesismay be associated with the impairment of the antioxidant defense cells in liver,the increase in lipid peroxidation, hepatic dysfunction and histological changes;estrogens prevent all these changes induced by aging. 17â-estradiol treatment wasinitiated in 12 month-old Wistar rats, and continued until 18 months of age. Ourresults showed that 17â-estradiol (E2) level in the serum of the aged untreated ratswas reduced by –32% in 18 month-old rats compared to the young animals (4-month-old). The superoxide dismutase (SOD), catalase (CAT), and gluthatione peroxidase(GPX) activities were reduced by –47, –46, and –29% respectively in old ratliver. In addition, the TBARs in liver and hepatic dysfunction parameters in plasmasuch as gamma-glutamyl transferase (GGT), phosphatase alkalin (PAL) as well asbilirubin level increased significantly in old rats, and histological changes were investigated.In E2-treated rats, protective effects were observed. Indeed, 17â-estradiolattenuates all changes induced by aging. The 17â-estradiol level was higher in old E2-treated rats compared to the control rats. Moreover, the SOD, CAT and GPX activitieswere higher by +28, +15, and +11% respectively. This anti-aging effect of estrogenswas clarified by a lower level of lipid peroxidation and liver dysfunction parametersas well as by histological observation (AU)

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