In vitro antioxidant activity of the prostatic secretory granules in rabbit semen after exposure to organic peroxides.
BACKGROUND
The prostate gland of rabbits produces numerous granules, which are specifically implicated in the inhibition of sperm capacitation during the first hours after mating. These granules are rich in vitamin E, but their role in the antioxidant protection of rabbit sperm has not been studied.


OBJECTIVE
The objectives of this study were to investigate whether the prostatic secretory granules (PSGs) could prevent sperm induced-lipid peroxidation and to verify a potential involvement of tocopherols from the PSGs to the sperm.


METHODS
Washed sperm samples taken from eighteen White New Zealand rabbits were either incubated with tert-butyl-hydroperoxide (t-BHP, an oxidative stressor) or with buffered Tyrode's medium for 1 hour. The same number of sperm samples that contained PSGs were subjected to the previously mentioned treatments and thiobarbituric acid reactive substances (TBARS), vitamin E compounds and the acrosome status were assessed.


RESULTS
The incubation of the sperm with t-BHP resulted in a noticeable production of TBARS (0.38 vs. 0.22 nmol/10(7) cells) and an associated decrease of alpha-tocopherol (alpha-T, 72.3 vs. 103.2 nmol/10(8) cells) with respect to the sperm samples containing PSGs. The sperm incubated with the PSGs had a higher amount of alpha-T compared to the control (292.2 vs. 251.0 nmol/10(8) cells). The acrosome status was not affected by the occurrence of the organic peroxide in the medium and the amount of capacitated sperm was lower when the PSGs were also present.


CONCLUSIONS
Overall, these results suggest that the PSGs may represent a source of protection for rabbit sperm against in vitro oxidative stress by supplying the sperm with endogenous alpha-T. This mechanism could be in part involved in the inhibition of sperm capacitation by the granules.
Mourvaki
Evangelia
E
Department of Applied Biology, Section of Animal Science, University of Perugia, Borgo XX Giugno 74, 06100, Perugia, Italy. vaggiemourvaki@mail.com
Cardinali
Raffaella
R
Dal Bosco
Alessandro
A
Castellini
Cesare
C
D020101:Acrosome Reaction / Q000187:drug effects; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D010545:Peroxides / Q000494:pharmacology*; D011467:Prostate / Q000187:drug effects / Q000378:metabolism*; D029584:Prostatic Secretory Proteins / Q000187:drug effects / Q000378:metabolism; D011817:Rabbits; D022142:Secretory Vesicles / Q000187:drug effects / Q000378:metabolism*; D012661:Semen / Q000187:drug effects* / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014810:Vitamin E / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
D000975:Antioxidants; D010545:Peroxides; D029584:Prostatic Secretory Proteins; D017392:Thiobarbituric Acid Reactive Substances; D014810:Vitamin E; D020122:tert-Butylhydroperoxide