Characterization of Testicular Angiotensin-Converting Enzyme before and after Semen Cryopreservation and in the Acrosome Reaction of Spermatozoids of Nelore Bulls

Abstract

The aim of this study was to characterize the testicular isoform of angiotensin-converting enzyme (tACE) before and after semen cryopreservation, and in the acrosome reaction of sperm from Nelore bulls in vitro. Ejaculates of 10 sexually mature Nelore bulls were used. After semen was collected, 1.0 mL of the ejaculate was used for the analysis and the rest was subjected to cryopreservation. Fresh semen before freezing, and frozen/thawed semen were centrifuged twice and the pellet was resuspended intyrode's albumin lactate pyruvate (TALP). Thereafter, 100 μL aliquots containing 100 × 10 6 spermatozoa were prepared. Aliquots of samples were used for western blot analysis, subjected to capacitation, and thereafter, acrosome reaction assays were performed in vitro. With the help of an anti-ACE monoclonal antibody, a