Department of Animal Sciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164, USA.
Reproduction. 2009 Oct;138(4):667-77. doi: 10.1530/REP-09-0020. Epub 2009 Jul 24.
Vascular endothelial growth factor-A (VEGFA) is a hypoxia-inducible peptide essential for angiogenesis and targets nonvascular cells in a variety of tissues and cell types. The objective of the current study was to determine the function of VEGF during testis development in bulls. We used an explant tissue culture and treatment approach to test the hypothesis that VEGFA-164 could regulate the biological activity of bovine germ cells. We demonstrate that VEGFA, KDR, and FLT1 proteins are expressed in germ and somatic cells in the bovine testis. Treatment of bovine testis tissue with VEGFA in vitro resulted in significantly more germ cells following 5 days of culture when compared with controls. Quantitative real-time RT-PCR analysis determined that VEGF treatment stimulated an intracellular response that prevents germ cell death in bovine testis tissue explants, as indicated by increased expression of BCL2 relative to BAX and decreased expression of BNIP3 at 3, 6, and 24 h during culture. Blocking VEGF activity in vitro using antisera against KDR and VEGF significantly reduced the number of germ cells in VEGF-treated testis tissue to control levels at 120 h. Testis grafting provided in vivo evidence that bovine testis tissue treated with VEGFA for 5 days in culture contained significantly more differentiating germ cells compared with controls. These findings support the conclusion that VEGF supports germ cell survival and sperm production in bulls.
血管内皮生长因子 A（VEGFA）是一种缺氧诱导肽，对血管生成至关重要，可作用于多种组织和细胞类型的非血管细胞。本研究的目的是确定 VEGFA 在公牛睾丸发育中的功能。我们使用组织培养和处理方法来检验假设，即 VEGFA-164 可以调节牛生殖细胞的生物学活性。我们证明 VEGFA、KDR 和 FLT1 蛋白在牛睾丸的生殖细胞和体细胞中表达。与对照组相比，VEGFA 在体外处理牛睾丸组织 5 天后，生殖细胞明显增多。实时定量 RT-PCR 分析确定，VEGF 处理刺激了一种细胞内反应，可防止牛睾丸组织外植体中的生殖细胞死亡，这表现为 BCL2 相对于 BAX 的表达增加，以及 BNIP3 在培养 3、6 和 24 小时时的表达降低。使用针对 KDR 和 VEGF 的抗血清在体外阻断 VEGF 活性，可使 VEGFA 处理的睾丸组织中的生殖细胞数量在 120 小时时显著减少至对照水平。睾丸移植提供了体内证据，表明在体外培养 5 天用 VEGFA 处理的牛睾丸组织中，分化的生殖细胞明显多于对照组。这些发现支持这样的结论，即 VEGF 支持公牛的生殖细胞存活和精子生成。
