ACTA VETERINARIA ET ZOOTECHNICA SINICA ›› 2018, Vol. 49 ›› Issue (9): 1889-1898.doi: 10.11843/j.issn.0366-6964.2018.09.010

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The Effects of Adding Exogenous VEGF on FLT-1 Expression during the Process of Ovine Oocytes Maturation in vitro in Three Different Ways

CAO Xin1, ZOU Yun-long2, LU Hui-ning2, GAO Dan-dan2, ZHOU Ping3, SHI Guo-qing3, YANG Ju-tian2*   

  1. 1. Experimental Teaching Department, Northwest Minzu University, Lanzhou 730030, China;
    2. Life Science and Engineering College of Northwest University for Nationalities, Lanzhou 730030, China;
    3. Institute of Animal Science, Xinjiang Academy of Agriculture and Reclamation Science, Shihezi 832000, China
  • Received:2018-04-08 Online:2018-09-23 Published:2018-09-23

Abstract:

The purpose of this research was to investigate the effect of exogenously added VEGF on the expression of the FLT-1 during the process of ovine oocytes maturation in vitro. Three different in vitro maturation culture methods were adopted:naked oocytes separate cultivation, granule cells with naked oocytes co-cultivation and cumulus-oocytes complexes (COCs) cultivation. Treatment groups were adding exogenous 5 ng·mL-1 vascular endothelial growth factor (VEGF) while control groups were not. The FLT-1 mRNA and protein expression levels in both ovine oocytes and granule cells were detected by qPCR and Western blot, respectively. The results indicated that:1)Adding VEGF could extremely significantly reduce the FLT-1 mRNA expression in granule cells in the co-cultivation treatment group at 12, 16 and 20 h, and the FLT-1 mRNA expression in COCs treatment group at 4, 8, 12, 16 and 24 h (P<0.01), and extremely significantly reduce the FLT-1 mRNA expression in oocytes in the co-cultivation treatment group at 12, 20 and 24 h, and the FLT-1 mRNA expression in COCs treatment group at 4, 8 and 12 h (P<0.01), but extremely significantly increase the FLT-1 mRNA expression in oocytes in the naked oocytes separate cultivation treatment group at 4-24 h (P<0.01). 2)Adding VEGF could extremely significantly reduce the expression of the FLT-1 protein in granule cells in both co-cultivation treatment group and COCs cultivation treatment group at 4-12 h (P<0.01). The expression of the granule cells FLT-1 protein in both naked oocytes co-cultivation treatment group and COCs cultivation treatment group showed a fluctuating downward trend. The granule cells FLT-1 protein expression in both COCs cultivation control group and COCs cultivation treatment group were higher than that of granule cells with naked oocytes co-cultivation treatment group at all time points.3)Among the 3 in vitro maturation culture methods, except for a sharp increase in the naked oocytes separate cultivation control group at 20-24 h, the oocytes FLT-1 protein expression in the other groups showed a downward trend of fluctuation. In conclusion, the FLT-1 has autocrine and paracrine effects in oocytes and granule cells. The expression of the FLT-1 mRNA and protein in oocyte are closely related to the presence or absence of peripheral granule cells, the number and the way of encapsulation. During in vitro culture environment, the addition of VEGF can effectively activate the FLT-1 mRNA expression, but at the same time combine the FLT-1 protein in order to play a biological effect promoting oocytes maturation, thus reducing the FLT-1 protein expression.

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