Analysis of apoptosis and DNA damage in bovine cumulus cells after exposure in vitro to different zinc concentrations

ANCHORDOQUY J.M.; PICCO S.J.; SEOANE A.; ANCHORDOQUY J.P.; PONZZINIBIO M.V.; MATTIOLI G.A.; PERAL GARCIA P.; FURNUS C.C.

CELL BIOLOGY INTERNATIONAL

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2010

1065-6995

The purpose of this study was to investigate the effect of zinc (Zn) concentration on cumulus cells (CC) during in vitro maturation. For this purpose, DNA integrity of CC by addition of different Zn concentrations 0 (Control); 0.7 £gg/mL (Zn1); 1.1 £gg/mL (Zn2) and 1.5 £gg/mL (Zn3) to culture medium was evaluated by comet assay. In addition, early apoptosis was analyzed by annexin staining assay. Cumulus cells treated with Zn showed a significant decrease in the DNA damage in a dose dependent manner. Comet assay analyzed for Tail Moment was significantly higher in cells cultured without Zn (Control, p ƒ¬ 0.01) respect to cells treated with Zn (Control: 5.24 ¡Ó16.05; Zn1: 1.13 ¡Ó5.31; Zn2: 0.10 ¡Ó0.36; Zn3: 0.017 ¡Ó0.06). All treatments were statistically different from the Control (p=0.014 for Zn1; p< 0.01 for Zn2 and Zn3). The frequency of apoptotic cells was higher in the Control group (Control: 0.142 ¡Ó0.07; Zn1: 0.109 ¡Ó 0.0328; Zn2:0.102 ¡Ó 0.013; Zn3: 0.0577 ¡Ó 0.019). Statistical differences were found between Control and Zn1 (p= 0.0308), Control and Zn2 (p= 0.0077), Control and Zn3 (p< 0.0001), Zn1 and Zn3 (p< 0.001) and Zn2 and Zn3 (p= 0.0004). No differences were found between Zn1 and Zn2. In conclusion, low Zn concentrations increase DNA damage and apoptosis in CC cultured in vitro. However, adequate Zn concentrations ¡§protect¡¨ the integrity of DNA molecule and diminish the percentage of apoptotic CC.