ON TESTIS AND EPlDlDYMlS OF RATS - Pondicherry University ...

01.. 1996). Expression of extracellular superoxidc dismutasc has bccn rcportcd in the
Sertoli cells of rat testis (Mruk and Cheng, 2000b). Mitochondria1 respiration has
been shown to be the main biological source of superoxide anion radicals under
physiological conditions (for review, see Chance er a/. 1979).
Antioxidants have been described as substances that either directly or
indirectly protect cells against adverse effects of xenobiotics, drugs, carcinogens and
toxic radicals reactions (Halliwell, 1995). Vitamin C (ascorbic acid), vitamin E (a
tocopherol), vitamin A, p-carotene, glutathione, superoxide dismutases, catalase,
glutathione peroxidasel reductase, nitric oxide synthase have been classified as
antioxidants (Krishna er a/.. 1996; Halliwell, 1999). The antioxidant properties of
ascorbic acid have been shown to enable it to protect tissues from reactive oxygen
species (Luck ef a/., 1995). Ascorbic acid has been shown to scavenge free radicals
caused as a result of environmental pollution and cellular metabolism (Dawson er 01..
1990). Vitamin E has been shown to function as a chain breaking antioxidant in the
cell membrane and plasma lipoproteins (Halliwell. 1999). Lipid peroxidation has
been shown to be initiated by hydroxy- (OH). alkoxy- (RO), and peroxy- (ROO)
radicals (Tramer el al., 1998). Cell membranes, which are structurally made up of
large amounts of PUFA has been shown to be highly susceptible to oxidative attack
and consequently changes in membrane fluidity, permeability. and cellular metabolic
functions (Lenzi el 01.. 1994). Co-administration of vitamin E with mercuric chloride
has been shown to prevent the reduction of epididymal sperm counts, motility and
morphology as well as succinic dehydrogenase, ATPase, sialic acid. ascorbic acid and
glutathione (Rao and Sharrna 2001).