Effect of cell membrane permeability protein on porcine oocyte vitrification.

BACKGROUND: The discovery of proteins with inherent cell membrane-translocating activity will expand our ability to study and manipulate various intracellular processes in living systems.

OBJECTIVE: We investigated the effect of TAT-EGFP (trans-activator of transcription-enhanced green fluorescent protein) intra-cellular delivery on the survival and development of mature porcine oocytes after cryopreservasion.

MATERIALS AND METHODS: Cumulus-oocyte complexes (COCs) collected from follicles 3 to 6 mm in diameter in abattoir-derived oocytesries of prepubertal gilts were on vitro matured (IVM). After IVM, the oocytes were used for TAT-EGFP delivery test and cryopreservation with and without TAT-EGFP supplementation. Oocyte viability was assayed by staining with fluorescein diacetate. Live oocytes were parthened and cultured in vitro, to assess their ability to be activated and to therefore develop.

RESULTS: The results show that the TAT-EGFP was well delivered into the nuclear of the Hela cell and oocytes also. In the medium toxic test, the proportion of viable oocytes in seven groups showed no significance. In vitrification experiments, the viability of oocytes in group supplemented with TAT-EGFP was significantly higher than that in the without TAT-EGFP group and the control groups (27.7%, 90.4%, and 100%, respectively). Among the three groups, the developmental abilities of oocytes in the supplement TAT-EGFP, EGFP and Control groups revealed that the vitrified group had a significantly reduced ability to undergo first cleavage (34.4%, 63.3%, and 69.0%, respectively).

CONCLUSION: the supplement of TAT-EGFP protein into vitrification medium does not affect the viability of the oocytes whereas it improved the viability and developmental potential of oocytes after it was vitrified.