Effect of zinc on DNA integrity of cumulus cells during oocyte in Vitro maturation

Zinc is an essential trace element. It has been known that a non adequate level of zinc can alter not only gene expression but also a variety of cellular functions with severe consequences on animal health. Little is known about the role of zinc on the reproductive performance of bovines, especially in oocyte maturation. The objective of the present study was to evaluate the impact of different zinc concentrations added to culture medium, on the DNA integrity of bovine cumulus cells during in vitro maturation of oocytes. Cumulus-oocyte coplexes obtained from an abattoir were cultured in IVM mediums contai- ning 30 (G1), 70 (G2), 110 (G3) and 150 (G4) µg/dl. At the end of IVM, cumulus cells were processed for Comet Assay. Result obtained with the comet assay shows a significant decrease in the percentage of cell with DNA migration from around 40% in G1 and G2 to 20% in G3 and G4 (p< 0,05). The intensity of DNA damage (DDV) was higher in G1 and G2 and sig- nificant different with G3 and G4 (p< 0,05). Taken into account, the relationship between in vitro maturation of cumulus cells oocytes complexes (COCs) and subsequent embryo development, it might be possible that different levels on Zinc con- centration during IVM have consequences on early embryo development. Key Word: Zinc, cumulus cells, comet assay