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Brandon Torrance

Fellow – Brandon Torrance

Mentor – Katrin Hinrichs

Project – Effect of Media and Incubation Conditions on Procaine-induced Hyperactivated Motility in Equine Sperm

Objective – Sperm hyperactivated motility is necessary for fertilization. It was recently reported that equine sperm exhibit hyperactivated motility, and fertility in vitro, when treated with procaine after incubation in bicarbonate- and albumin-containing medium (“capacitating medium”) in air. This study was conducted to examine the effects of bicarbonate and CO2 atmosphere on procaine-induced hyperactivated motility in equine sperm.

Animals or Sample Population – Semen was collected from a healthy, fertile stallion.

Procedure – Sperm were treated with 5 mM procaine at 0 h, or after incubation for 6 h in noncapacitating medium in air (NC6); capacitating medium in air (C6Air); or capacitating medium in 5% CO2 (C6CO2). Sperm were evaluated 5 min after procaine addition, using a computer-assisted sperm motility analyzer.

Results – At 0 h, procaine addition induced significant increases in curvilinear velocity (VCL) and amplitude of lateral head movement (ALH), and significant decreases in linearity (LIN) and average path velocity (VAP). Addition of procaine in treatment C6Air induced significant decreases in straight line velocity (VSL), straightness (STR), and LIN. In treatment C6CO2, procaine addition caused similar significant changes in STR and LIN, but also significant increases in VCL and ALH. Similarly, procaine addition in treatment NC6 induced significant decreases in VSL, STR, and LIN, and significant increases in VCL and ALH.

Conclusions and Clinical Relevance – These results indicate that hyperactivated motility of equine sperm can be induced under varied culture environments, but that environment influences motility parameters. Further study is required to apply these findings to in vitro fertilization in the horse.