AIMTo investigate the distribution of c-myb, an oncoprotein, in mouse oocytes-cumulus cell complex and sperm immunohistochemically.

METHODSTo study the effect of c-myb on mouse fertilization in vitro, various concentration of c-myb antisense-oligodeoxynucleotides (c-myb ASODNs) were incubated with sperms and oocytes during fertilization. To explore the possible mechanism involved in fertilization, the relationship between c-myb ASODNs and GABA or dbcAMP or Verapamil or Progesterone in fertilization was also observed by immunohistochemical methods.

RESULTSc-myb oncoprotein was observed on the nucleus of cumulus cell and head of sperm. c-myb ASODNs inhibited the rate of fertilization in vitro in a dose-dependent way. The fertilization rates of the control group, low (5 micromol/L), medium (10 micromol/L), high (20 micromol/L) concentration c-myb ASODNs groups and nonsense tat oligodeoxynucleotides (20 micromol/L) group were 34.97%, 30.89%, 20.14%, 16.68%, 34.47%, respectively. All of GABA, Progesterone and dbcAMP inversed the c-myb ASODNs inhibition effects on fertilization rate, but neither of them showed significant effect on the percentages of immunohistochemical stain of Myb on sperm and cumulus cells. By contrast, Verapamil inhibited the fertilization rate. Co-treated with c-myb ASODNs, Verapamil showed synergic inhibiting effects on the fertilization with c-myb ASODNs. Verapamil also inhibited the expression of Myb on head of sperm. The fertilization rates of the control group, medium (10 micromol/L) concentration c-myb ASODNs group, GABA group, P4 group, Verapamil group, dbcAMP group were 34.81%, 22.96%, 40.83%, 39.12%, 7.46%, 40.61%, respectively.

CONCLUSIONc-myb ASODNs is closely correlated with fertilization. Verapamil can inhibit fertilization in vitro through regulating Myb expression of sperm, while GABA, dbcAMP and Verapamil may affect the process of fertilization through the way other than Myb expression.