The addition of heat shock protein 70 to in vitro maturation medium improves the post-thaw quality of vitrified oocytes.

BACKGROUND: The application of biotechnology in the field of animal husbandry in Indonesia is continuously being developed to increase livestock productivity and reproductivity. Embryo transfer technology is closely related to in vitro fertilization (IVF) because IVF is used to produce high-efficiency embryos. AIM: This study aims to demonstrate that heat shock protein 70 (HSP70) plays a role in providing cell protection against temperature stress during oocyte vitrification. METHODS: This experimental laboratory research was conducted divided into three research stages: The first stage is a descriptive study aimed at describing the presence of HSP70 expression in bovine oocytes. The second stage is an examination of cytochrome c expression and caspase 3 expression in fresh oocytes, post-in vitro maturation (IVM) oocytes, and post-thawing oocytes. The third stage is an examination of apoptosis using the Terminal deoxynucleotidyl transferase dUTP Nick-End Labeling method to determine the occurrence of apoptosis in fresh oocytes, post-IVM oocytes, and post-thawing oocytes. RESULTS: Post-IVM oocytes showed a decrease in the percentage of oocytes with normal morphology, followed by an increase in apoptosis, HSP70, Cyt-c, and caspase-3 expression. The addition of HSP70 to the vitrification medium resulted in the highest percentage of apoptotic oocytes. The percentage of oocytes with normal morphology and undergoing apoptosis was not linear with the expression of Cyt-c and caspase 9. CONCLUSION: HSP70 plays a role in providing cell protection against temperature stress during oocyte vitrification. HSP70 expression is observed in fresh oocytes, post-IVM oocytes, and post-vitrification oocytes without HSP70 supplementation. Cytochrome c expression in various oocyte preparations.