Table_1_Supplementation with fibroblast growth factor 7 during in vitro maturation of porcine cumulus-oocyte complexes improves oocyte maturation and early embryonic development.DOCX

In vitro generation of porcine embryos is an indispensable method in the realms of both agriculture and biomedicine. Nonetheless, the extant procedures encounter substantial obstacles pertaining to both the caliber and efficacy of the produced embryos, necessitating extensive research to in vitro maturation (IVM), the seminal commencement phase. One potentially fruitful approach may lie in refining the media and supplements composition utilized for oocyte maturation. Fibroblast growth factor-7 (FGF7), alternatively termed keratinocyte growth factor, is a theca-derived cytokine integral to folliculogenesis. This study aimed to examine the ramifications of supplementing FGF7 during the IVM phase. To determine the FGF7 location and its receptor in porcine ovaries, immunohistochemistry was executed based on follicle size categories (1–2, 3–6, and 7–9 mm). Regardless of follicle size, it was determined that FGF7 was expressed in theca and granulosa cells (GCs), whereas the FGF7 receptor was only expressed in the GCs of the larger follicles. During the IVM process, the maturation medium was supplied with various concentrations of FGF7, aiming to mature porcine cumulus-oocyte complexes (COCs). The data indicated a significant augmentation in the nuclear maturation rate only within the group treated with 10 ng/mL of FGF7 (p < 0.05). Post-IVM, the oocytes diameter exhibited a significant expansion in all groups that received FGF7 supplementation (p < 0.05). Additionally, all FGF7-supplemented groups exhibited a substantial elevation in intracellular glutathione levels, coupled with a noticeable reduction in reactive oxygen species levels (p < 0.05). With respect to gene expressions related to apoptosis, FGF7 treatment elicited a downregulation of pro-apoptotic genes and an upregulation of anti-apoptotic genes. The expression of genes associated with antioxidants underwent a significant enhancement (p < 0.05). In terms of the FGF7 signaling pathway-associated genes, there was a significant elevation in the mRNA expression of ERK1, ERK2, c-kit, and KITLG (p < 0.05). Remarkably, the group of 10 ng/mL of FGF7 demonstrated an appreciable uptick in the blastocyst formation rate during embryonic development post-parthenogenetic activation (p < 0.05). In conclusion, the FGF7 supplementation during IVM substantially augments the quality of matured oocytes and facilitates the subsequent development of parthenogenetically activated embryos. These results offer fresh perspectives on improved maturation and following in vitro evolution of porcine oocytes.

在农业与生物医药领域，体外培育猪胚胎是一项不可或缺的技术。然而，现行的技术方法在胚胎的品质与效率上均遭遇重大挑战，亟需对体外成熟（IVM）这一关键阶段的深入研究。优化卵母细胞成熟过程中使用的培养基和补充剂成分，可能是一条颇具潜力的途径。成纤维细胞生长因子-7（FGF7），亦称角质细胞生长因子，是一种源于卵巢卵泡膜的细胞因子，对于卵泡发生至关重要。本研究旨在探讨在IVM阶段补充FGF7的后果。为了确定FGF7在猪卵巢中的位置及其受体，基于卵泡大小分类（1-2毫米、3-6毫米和7-9毫米）进行了免疫组化实验。无论卵泡大小如何，均发现FGF7在卵泡膜细胞和颗粒细胞（GCs）中表达，而FGF7受体仅在较大卵泡的GCs中表达。在IVM过程中，成熟培养基中添加了不同浓度的FGF7，以促进猪的卵母细胞-卵丘复合体（COCs）成熟。数据显示，仅在用10 ng/mL FGF7处理的组中观察到核成熟率的显著提升（p < 0.05）。在IVM后，接受FGF7补充的各组卵母细胞直径均显著增加（p < 0.05）。此外，所有接受FGF7补充的组均表现出细胞内谷胱甘肽水平的显著升高，以及活性氧水平的有显著降低（p < 0.05）。在凋亡相关基因表达方面，FGF7处理导致了促凋亡基因的下调及抗凋亡基因的上调。与抗氧化剂相关的基因表达显著增强（p < 0.05）。就FGF7信号通路相关基因而言，ERK1、ERK2、c-kit和KITLG的mRNA表达显著增加（p < 0.05）。值得注意的是，在胚胎发育后的单倍体激活过程中，10 ng/mL FGF7组的囊胚形成率有显著提升（p < 0.05）。综上所述，在IVM阶段补充FGF7显著提高了成熟卵母细胞的质量，并促进了后续单倍体激活胚胎的发育。这些研究结果为猪卵母细胞的成熟及体外进化提供了新的视角。