Improved cleavage of bovine ICSI ova cultured in heparin-containing medium

Although heparin plays an important role in bovine sperm capacitation, there is no direct evidence for a role in embryonic development. The present study was designed to examine the effect of heparin on early development of bovine zygotes obtained by intracytoplasmic sperm injection (ICSI). Spermatozoa were treated with or without heparin, and the ICSI ova were cultured in a chemically defined medium + BSA, with or without heparin. Treatment of spermatozoa with heparin before ICSI or heparin in post-ICSI culture medium for 18 or 24h had a beneficial effect on pronuclear formation, cleavage rate (63% versus 76-83%), and number of cells in blastocysts (68 cells versus 82-109 cells; P < 0.05).