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

1.4 Effect of oxidative stress on mvlc reproduction
Reactive oxygen species (ROS) have been shown as an important part of thc
defense mechanisms against infection, but excessive generation of free radicals have
been shown to damage tissues (Garg and Bansal, 2000). Reactive oxygen and
reactive nitrogen species have been shown to play a significant role in male
reproduction (for review, see Sikka, 2001). ROS have been shown to be formed in
both physiological and pathological conditions in human spermatozoa due to their
high reactivity they may interact with biomolecules inducing oxidative stress
(Ichikawa el 01.. 1999). which severely impair male reproduction as indicated by
reduction in fertility (for review, see Sikka, 2001). In the male genital tract,
spermatozoa and leukocytes including neutrophils and macrophages have been shown
to generate ROS which involved in the regulation of sperm function. Excessive
production of ROS has been shown to cause oxidative stress in sperm (Ochsendorf,
1999).
Induction of the activities of intracellular oxidases in the testicular tissue or
spermatozoa have been shown to result in the production of nanomolar levels of
superoxide anion resulting in direct interaction with signalling mechanisms (Aitken
er 01.. 1989). Semen samples from infertile patients have been shown to contain high
superoxide anion generation. Prolonged inhibition of sperm mitochondria1 function
by the ROS have been suggested as the cause of inhibition of sperm motility (Aitken
er 01.. 1991; Kessopoulou er ol., 1992). Sperm viability could be improved by
addition of catalase to the medium, implying that in their steady state these cells
generate hydrogen peroxide, which can be deleterious to their survival (Mac Leod.
1943).
t-lydropen peroxide has been shown to k n stnhlr rcnctlvc oxygen sprcics with
high biological diffusion properties and has been reported to transvrrsc thc plasma
and nuclear membranes causing DNA adduct formation (for review. see Sikka. 2001).
Peroxide derived ROS has been shown to react with transition metals such as iron
present in biological systems and affect signaling or tissue injury processes (Peltola el