in vitro survival rate of bovine oocytes following vitrification in glass capillary micropipette (gcm)

the purpose of this study was to evaluate the use of glass capillary micropipette (gcm) as a vessel forvitrification of bovine oocytes. cumulus-oocyte complexes (cocs) were obtained from slaughter-house andwashed 5 to 6 times in the washing medium (tcm-199 + 20% fbs) and randomly assigned to treatment andcontrol group. in the first step of vitrification, cocs were exposed to first vitrification solution (vs1) (10%ethylene glycol (eg), 10% dmso in holding medium (tcm-199 + 10% fbs: hm)) for 1 min at roomtemperature and then placed in vs2 solution (20% eg, 20% dmso in hm) for 25 sec and immediately wereloaded into the gcm vessel. the filled portion of gcm vessels were placed in liquid nitrogen (ln2) for 3 to5 sec and then completely immersed and stored there. the oocytes were thawed by immersing the capillaryend of the straw in 1 ml of 0.25 m sucrose in hm and gently expelling the contents. after 1 min the oocyteswere transferred into 100 μl of 0.15 m sucrose in hm for another 5 min and then washed with hm twice. forexamining the in vitro developmental potential of vitrified-warmed oocytes, the oocytes were placed in 50 μldroplet of maturation medium (tcm-199 + 10% fbs + 10 iu/ml pmsg + 5 iu/ml hcg) covered withparaffin oil in a co2 incubator at 38.5ºc for 24 hrs. a high proportion of morphologically normal oocytes(90%) was recovered after vitrification-warming. the percentage of live oocytes after 24 hrs when testedwith trypan blue in gcm group was 85.18%, significantly did not differ from control group (90%). theproportion of oocytes which were found to have undergone nuclear maturation did not show statisticaldifference between the control and gcm group (61.29% vs 40%, respectively). the results of present studydemonstrated that vitrification of immature bovine oocytes in the gcm vessels and eg + dmso solutionhave high survival rate.