Combined treatment with IGF1, CoQ10, and melatonin improves the quality of bovine oocytes and heat-shocked blastocysts†.

Heat stress significantly impairs cattle fertility, particularly affecting oocytes and developing blastocysts. Developing strategies to improve embryonic development under heat stress is crucial for advancing the cattle breeding industry. This study evaluated the effects of a combined treatment with insulin-like growth factor 1 (IGF1), coenzyme Q10 (CoQ10), and melatonin (MT) (i.e., IGF1 + CoQ10 + MT) on oocyte competence and gene expression in the formed blastocysts. Bovine in vitro fertilization blastocysts were assessed under heat shock (41°C for 12 h) and control conditions (38.5°C). The combined supplementation of IGF1 (100 ng/mL), CoQ10 (50 μM), and MT (1 μM) during in vitro maturation and in vitro culture improved oocyte quality and competence by reducing reactive oxygen species levels and apoptosis, increasing mitochondrial membrane potential (ΔΨm), optimizing mitochondrial distribution, and upregulating quality-related genes. Heat shock decreased adenosine triphosphate (ATP) content, increased apoptosis, and affected gene expression related to development, apoptosis, ubiquitination, and autophagy, impacting blastocyst development. The combined treatment mitigated heat shock damage by enhancing ATP content, reducing apoptosis, and improving gene expression, thus improving blastocyst quality.