Melatonin and caffeine supplementation in cryopreservation of sperm: effects on sperm function and sperm-ovocyte interaction

• Grant number: 19/18571-0
• Support Opportunities: Regular Research Grants
• Duration: April 01, 2021 - September 30, 2023
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Juliana Risso Pariz
• Grantee: Juliana Risso Pariz
• Host Institution: Diretoria de Graduação. Universidade Metodista de São Paulo (UMESP). Instituto Metodista de Ensino Superior (IMS). São Bernardo do Campo , SP, Brazil
• Associated researchers: Joel Drevet ; Jorge Hallak ; Polina V. Lishko ; Raul Segundo Sanchez Gutierrez

Abstract

The cryopreservation process can damage sperm and alter their structural and functional characteristics. Plasma, nuclear membranes and cellular organelles can suffer from the freezing and thawing process. The main objective is to study the effects of melatonin, a powerful antioxidant, and caffeine, a stimulating substance, on the functional characteristics of sperm, the oxidative status of sperm and oocyte-sperm interactions in post-thaw human sperm. For this purpose, 250 seminal samples of men aged 19 to 45 years will be included. After the initial semen analysis, the samples will be supplemented with melatonin before cryopreservation and caffeine after thawing. The following parameters will be evaluated before and after sperm cryopreservation: membrane lipid peroxidation, mitochondrial activity, DNA integrity, reactive oxygen species level, total antioxidant capacity, glutathione activity, plasma membrane and acrosome integrity, hyaluronan binding and capacitation assays. Sperm cryopreservation will be done by slow freezing and vitrification to determine the best cryopreservation method. In addition, a study comparing 0.01mM, 2mM and 3mM of melatonin will be conducted in advance to determine the best melatonin concentration and use it during this project. The student's t-test and analysis of variance will be used to compare the means, followed by the Tukey test or the Mann-Whitney U-test. Sensitivity and specificity will be calculated to predict cryosurvival rates by Receiver Operating Characteristic (ROC) curve from ROS level thresholds, antioxidant concentration and other seminal parameters. We hope to clarify the advantages and disadvantages of each cryopreservation method based on a thorough evaluation of the basic parameters of the semen, the functional characteristics of the semen, the oxidative profile of the semen and the interaction of the semen and oocyte. (AU)