Ảnh hưởng giai đoạn bổ sung yếu tố tăng trưởng nội mao mạch trong môi trường nuôi thành thục tế bào trứng đến sự thành thục nhân và phát triển của phôi đơn tính ở heo thu từ nang noãn nhỏ

Nguyễn Văn Ba, Giang Thị Thanh Nhàn, Nguyễn Thị Lệ Hương, Phạm Thu Thảo, Nguyễn Khánh Vân và Phạm Doãn Lân.

Abstract

Stage-dependent effect of Vascular Endothelial Growth Factor protein in the matuaration
medium on nuclear maturation and developmental competence of parthenogenetic embryos of
porcine oocytes derived from small follicles
This study aimed to evaluate the stage-dependent effect of VEGF protein supplementation
in maturation medium on nuclear maturation and further parthenogenetic embryos development
of porcine oocytes derived from small follicles. Cumulus-Oocyte Complexes (COCs) with more
than 2 layers were collected from medium follicles (MF) and small follicles (SF) for in vitro
maturation (IVM) in 44hrs, the oocyte with the first polar body was subjected to parthenogenetic
activation by ethanol. Result showed that the nuclear maturation rate of MF-derived oocytes was
significantly higher than SF-derived oocytes in condition of without VEGF supplementation (74.6
and 45.4%, P<0.05). Furthermore, the result also indicated that the stage-dependent effect of VEGF
supplementation in maturation medium on nuclear maturation, cleavage rate and blastocyst
formation of SF-derived oocytes was found. The percentage of nuclear maturation was highest in
SF-derived oocytes supplemented with VEGF during the first 22hrs of IVM (73.9%) as compared
to the 44hr-treated group (71.2%), last-22hr-treated group (58.5%) and non-treated group (45.4%).
Meanwhile, no significant differences between non-treated MF-derived (74.6%, P>0.05), first-22hr
and 44hrs group after IVM were observed. After parthenogenetically activation was applied, the
cleavage and blastocysts rate in SF-derived oocytes of the 44hr-treated group (70.7 and 24.4%,
respectively) and first-22hr-treated group (74.3 and 28.3%, respectively) also showed no significant
differences to MF group (79.9 and 31.7%, respectively, P>0.05). In conclusion, supplementing 250
ng/ml of VEGF during the first 22hrs or entire 44hrs of IVM not only enhance the nuclear maturation
but also increase the cleavage rate and blastocyst formation of oocytes derived from small follicles.