Virginia Via Research Day Book 2026

Medical Student Research Biomedical

02 SPERM TRANSPORT AND MATURATION WITHIN THE FEMALE REPRODUCTIVE TRACT

Paushaly Sau, MSc, BS, BA, OMS-II; Amy Ellis, MSc, BSc; Celine Jones, MSc; Kevin Coward, PhD; Marc Yeste, PhD Corresponding author: psau@vt.vcom.edu

Nuffield Department of Women’s and Reproductive Health, University of Oxford Biotechnology of Animal and Human Reproduction (TechnoSperm), Unit of Cell Biology, Department of Biology, Faculty of Sciences, University of Girona

reproductive tract”, “fertilization”, “hyperactivation”, “in vitro fertilization (IVF)”, “intrauterine insemination”, “male infertility”, “NETosis”, “PKA pathway”, “PKC pathway”, “sperm maturation”, and “thermotaxis”. Eligible studies examined mechanisms of sperm development and motility, diagnostic approaches to male factor infertility, or outcomes related to ART. Titles and abstracts were screened for relevance, and full-text articles meeting inclusion criteria were included. Key findings were summarized in a literature review and figures were created to map current evidence and identify knowledge gaps. Results: This review identified evidence describing the complex molecular and physiological processes required for sperm to reach and fertilize the oocyte. Key findings highlighted the role of transport through the female reproductive tract, alongside chemotaxis, thermotaxis, and rheotaxis, in selecting highly viable sperm. Multiple interconnected molecular pathways, including PKA, PKC, IZUMO JUNO, and PLCζ, regulate capacitation, acrosome reaction, zona pellucida penetration, gamete fusion, and oocyte activation. Crosstalk among pathways, particularly ion channel interactions during capacitation and PKA/PKC signaling interplay,

provides additional regulation. This literature review also identifies unresolved mechanisms, including precise triggers for acrosome reaction timing, Ca²⁺ oscillatory signaling in oocytes, and the possible presence of additional sperm-derived oocyte-activating factors. Conclusion: This review demonstrates that sperm motility, maturation, and fertilization rely on highly coordinated molecular pathways that can be disrupted in a range of male infertility conditions, including asthenozoospermia, teratozoospermia, and defects in zona pellucida interaction. Expanding understanding of these mechanisms is essential for identifying new diagnostic and therapeutic targets. Gaps in current knowledge, such as acrosome reaction regulation, ion channel signaling, and oocyte activation factors, highlight directions for future research. Insights from these mechanisms continue to inform the refinement of ART, including sperm-selection and preparation techniques, to improve clinical outcomes for patients with male factor infertility.

Context: Infertility is a prevalent issue affecting approximately 186 million people worldwide. Male factor infertility accounts for 40-50% of infertility, making it an important field of interest. A deeper study of the finely regulated sperm transport and maturation pathways, and their role in fertilization, may help to develop scientific understanding of reproductive science and therapeutic treatments for male infertility. Objective and/or Hypothesis: This literature review will describe the obstacles posed by the female reproductive system to prevent any morphologically or genetically suboptimal sperm from fertilizing the oocyte, the molecular mechanisms sperm undergo to achieve maturation and fertilization, and how these pathways can be utilized to further improve assisted reproductive technologies (ART) in treating male infertility. Methods: A scoping review was conducted using the NCBI database to identify studies published between 2010 and 2025 related to sperm motility, sperm maturation, male factor infertility, and assisted reproductive technologies. Search terms included combinations of key terms such as “Assisted Reproductive Technologies”, “active transport, “acrosomal reaction”, “chemotaxis”, “female

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2026 Research Recognition Day