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Maximising human sperm intracellular
2+ [Ca ]i
Kane, Shruti1; Lester, Douglas1; Scott, Cameron1; Barratt, Christopher2; Martins da Silva, Sarah2; Brown, Sean1 1School of Applied Sciences, Abertay University; 2Reproductive Medicine Research Group, University of Dundee; Email: s.kane1800@abertay.ac.uk
Study design
Introduction The Problem: • Impaired motility is a common cause of sperm dysfunction and male infertility • There is a lack of understanding of the physiological regulation of the sperm cells Significance: • The CatSper channel is the principal ion channel in human sperm with polymodal modes of activation • [Ca2+]i via the CatSper channel in human sperm regulates sperm motility and acrosome reaction which when abnormal are associated with male infertility and failed IVF treatment Research AIM: To investigate methods to maximum calcium potential in human sperm
Example: Population [Ca2+]i Measurement
ΔF/F0 Ca2+ (%)
150
Blank Agonist Ionophore A23187
100 50 0 -50
100
200
300
Time (Sec)
Results Figure 1: Technical factors affect peak [Ca2+]i in human sperm cells after exposure to physiological agonists
Figure 3: Nh4Cl acts via a third pH-sensitive mode of CatSper activation which is distinct from P4 & PGE
Figure 2: Addition of combined P4/PGE/Nh4Cl provides a larger sustained peak [Ca2+]i along with higher total [Ca2+]i response
Conclusions: A potential new therapy?
► Significantly higher area under the curve with combined agonist induced [Ca2+]i measurements
References (1) Agarwal A, Mulgund A, Hamada A, Chyatte MR. A unique view on male infertility around the globe. Reprod Biol Endocrinol 2015 April 26;13:37-1. (2) Brown SG, Costello S, Kelly MC, Ramalingam M, Drew E, Publicover SJ, et al. Complex CatSper-dependent and independent [Ca2+]i signalling in human spermatozoa induced by follicular fluid. Hum Reprod 2017 October 01;32(10):1995-2006.
• Combined P4/PGE/NH4Cl induces a significantly larger sustained [Ca2+]i influx compared with agonists alone or in pairs • Triple mix of P4/PGE/Nh4Cl can be used as a treatment strategy for patients with low sperm motility and to increase success during IVF/IUI treatments • Nh4Cl activates the CatSper channel from a mode distinct from P4 & PGE and primes the channel for maximum calcium activation and acrosome reaction • Using these results, we can now reliably maximise CatSper response and progress this to investigating effects on motility and acrosome reaction in normal and patient sperm
Acknowledgements • Supervisory team: Dr Sean Brown, Dr Scott Cameron & Dr Douglas Lester • Dr Sarah Martins da Silva & Prof. Christopher Barratt, University of Dundee • Funding body: Rlinks & Northwood trust
Abertay University is an operating name of the University of Abertay Dundee, a charity registered in Scotland, No: SC016040.