Ma Dongxue, Akthar Ihshan, Hashimoto Taiyo, Marey Mohamed A, Kusama Kazuya, Imakawa Kazuhiko, Shimada Masayuki, Miyamoto Akio
Global Agromedicine Research Center (GAMRC), Obihiro University of Agriculture and Veterinary Medicine, Obihiro, 080-8555, Japan.
Department of Theriogenology, Faculty of Veterinary Medicine, Damanhour University, Behera, Egypt.
Sci Rep. 2025 Jul 9;15(1):24678. doi: 10.1038/s41598-025-09570-2.
Improving the quality and developmental competence of in vitro-produced (IVP) embryos is crucial for assisted reproductive technologies. Recently, we demonstrated that TLR2, an innate immune receptor, is expressed in bovine sperm and their activation improves fertilization and subsequent embryo development. However, its role in early embryo development is poorly understood. This study investigated the impact of activation of early embryonic TLR2 on IVP bovine embryo development. The immunofluorescence and western blot analyses confirmed robust TLR2 expression in early embryonic stages. Embryos were treated at 36 h post-insemination (hpi), with 100 ng/ml of TLR2 agonist and cultured in vitro and showed increased blastocyst rates and faster growth speed. Additionally, TLR2 activation slightly increased basal calcium levels and induced autophagy while suppressing cathepsin B activity and DNA damage, leading to reduced apoptosis in embryos. Together, these findings indicate that embryo TLR2 is involved in embryo development competence via a slight increase in the basal cytosolic calcium and subsequent embryo metabolic activities, autophagy induction, and reduction of apoptosis levels. These results provide a promising approach for producing highly competent good-quality embryos for improving the efficiency of IVP bovine embryos.
提高体外生产（IVP）胚胎的质量和发育能力对于辅助生殖技术至关重要。最近，我们证明了Toll样受体2（TLR2），一种天然免疫受体，在牛精子中表达，其激活可改善受精及随后的胚胎发育。然而，其在早期胚胎发育中的作用尚不清楚。本研究调查了早期胚胎TLR2激活对IVP牛胚胎发育的影响。免疫荧光和蛋白质印迹分析证实了TLR2在早期胚胎阶段的强烈表达。在授精后36小时（hpi）用100 ng/ml的TLR2激动剂处理胚胎，并进行体外培养，结果显示囊胚率增加且生长速度加快。此外，TLR2激活略微增加了基础钙水平并诱导了自噬，同时抑制了组织蛋白酶B活性和DNA损伤，从而减少了胚胎中的细胞凋亡。总之，这些发现表明胚胎TLR2通过略微增加基础胞质钙水平以及随后的胚胎代谢活动、自噬诱导和凋亡水平降低来参与胚胎发育能力。这些结果为生产高质量、高发育能力的胚胎以提高IVP牛胚胎的效率提供了一种有前景的方法。
