Abstract

GUSTINA, S. et al. Hydrogen peroxide concentration and DNA fragmentation of buffalo oocytes matured in sericin-supplemented maturation medium. S. Afr. j. anim. sci. [online]. 2019, vol.49, n.2, pp.227-234. ISSN 2221-4062.  http://dx.doi.org/10.4314/sajas.v49i2.3.

This study was conducted to investigate the effects of sericin on meiotic maturation, hydrogen peroxide (H₂O₂) concentration and deoxyribonucleic acid (DNA) fragmentation in buffalo oocytes. Oocytes were matured in vitro in tissue culture medium (TCM-199) with in vitro maturation (IVM) groups under several conditions, namely without bovine serum albumin (-BSA), (+BSA), and 0.025%, 0.05%, 0.1% and 0.25% (w/v) sericin. The results showed that supplementation of the maturation medium with 0.05% sericin significantly increased the rate of oocytes that reach metaphase II compared with other groups, except for the 0.025% sericin-treated group. Intracellular H₂O₂ concentrations in oocytes of all groups were measured using 2',7'-dichlorodihydrofluorescein diacetate (DCHFDA). The concentration of H₂O₂ in matured oocytes treated with 0.05% sericin was lower than in other groups. DNA fragmentation and the nuclear status of oocytes were examined using the terminal deoxyribonucleotidyl transferase-mediated dUTP digoxigenin nick end-labelling (TUNEL) method. The total proportion of TUNEL-positive oocytes at the MII stage was lower in the 0.05% sericin group. The results indicate that addition of 0.05% sericin to the maturation medium may improve nuclear maturation and may inhibit DNA fragmentation in oocytes by decreasing H₂O₂ concentrations.

Keywords : antioxidant; apoptosis; reactive oxygen species.

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