Abstract

Background:
The application of biotechnology in the field of animal husbandry in Indonesia continues to be developed to increase livestock productivity and reproductivity. Embryo transfer technology is closely related to in vitro fertilization (IVF), because IVF is used as a means to produce embryos with a high level of efficiency.

Aim:
This study aims to prove that the Heat Shock Protein 70 (HSP70) has a role in providing cell protection against temperature stress during the vitrification process of oocytes.

Methods:
This research is an experimental laboratory research conducted divided into 3 (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-IVM oocytes, post-thawing oocytes; The third stage is an examination of apoptosis using the TUNEL method to see the occurrence of apoptosis in fresh oocytes, post-IVM oocytes, post-thawing oocytes.

Results:
Post-IVM oocytes showed a decrease in the percentage of oocytes with normal morphology, followed by an increase in the percentage of apoptosis, HSP70, Cyt-C, and caspase-3 expression. The addition of HSP70 in the vitrification medium resulted in the highest percentage of oocytes undergoing apoptosis. The percentage of oocytes undergoing apoptosis and with normal morphology was not linear with the expression of Cyt-c and caspase 9.

Conclusion:
Heat Shock Protein 70 plays a role in providing cell protection against temperature stress during the oocyte vitrification process. HSP70 expression is seen in fresh oocytes, post-IVM oocytes, and post-vitrification oocytes without HSP70 supplementation. Cytochrome c expression is seen in various oocyte preparations.

Key words: Apoptosis; Bovine oocyte; Caspase 3; Cytochrome-c.