Antioxidant capacity of the epididymis

The human epididymis provides an optimal environment for the storage and ma turation of spermatozoa, However, the ability of the epididymis to protect spermatozoa from oxidative attack whilst stored at this site, through the l ocal actions of antioxidants, has not thus far been well studied. This stud y assessed the contribution of the epididymis to seminal plasma antioxidant activity, by comparing the semen of normozoospermic and vasectomized men. Total seminal plasma antioxidant activity was measured, as were concentrati ons of urate, ascorbate and thiols, antioxidants that are abundant in human semen. Thiobarbituric acid reactive species (TBARS) were measured to indic ate lipid peroxidation, Total antioxidant activity and thiol content were s ignificantly lower (P < 0.05) in the plasma from vasectomized men compared with that of normozoospermic donors, Ascorbate and urate were found at simi lar concentrations in the plasma of both groups, The concentration of TEARS was significantly higher (P < 0.001) in the semen from vasectomized indivi duals compared with the normozoospermic group. The results indicate that th e epididymis contributes to the antioxidant capacity of seminal plasma and possesses region-specific antioxidant activity, which may potentially prote ct spermatozoa from oxidative attack during storage at this site.