Addition of IGF-I during Holding Time increases sperm cryotolerance in boars: How does this protein promote this effect?

• Grant number: 25/00578-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2025
• End date: July 31, 2027
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Reproduction
• Principal Investigator: André Furugen Cesar de Andrade
• Grantee: Isadora Ribeiro de Martino
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The project aims to identify the IGF-I receptor in swine sperm and evaluate the effects of adding different concentrations of IGF-I at the Holding Time (HT) on the cryopreservation process. Semen from boars will be used, and in the first experiment the ejaculate will be divided between treatments with the following concentrations of IGF-I: 50 ng/ml, 100 ng/ml, 150 ng/ml, in addition to the control group without addition of the hormone. For the second experiment, refrigerated and cryopreserved semen will be collected and prepared, followed by immunolocalization of the IGF-I receptor through immunohistochemistry and Western blot. After collection, the semen will be diluted in a commercial extender (Vitasem¿, Megapor, Spain) containing IGF-I. The samples will be kept at the HT, where aliquots will be made for ATP measurement. The samples will be centrifuged, followed by dilution of the sperm pellet with fraction A of the freezing diluent, which will remain for 180 minutes at 5°C. Fraction B of the diluent will then be added, and the samples will be packaged in straws, which will undergo cryopreservation, and finally the straws will be stored in liquid nitrogen (-196°C). After thawing, CASA, flow cytometry and ATP assays will be performed. In this way, it is expected to identify, for the first time, the presence of IGF-I receptors in swine sperm cells. In addition, it is sought to determine concentrations that promote an increase in the concentration of intracellular ATP, which would lead to improvements in the parameters of motility and integrity of the plasma and acrosomal membranes, attributed to the action of IGF-I during HT. (AU)