Introduction: Potassium channels are essential for the physiological regulation of cell excitability through control of membrane hyperpolarisation. In human sperm slo1 and/or 3 have been proposed to mediate this function (Mannowetz et al. 2013, Mansell et al. 2014). However, to date there is no information on dysfunction in men and the consequence of this for their fertility.
Materials and methods: Men undergoing ICSI treatment or recalled as part of failed fertility clinic attended Ninewells Assisted Conception Unit, Dundee. Surplus semen samples at time of treatment, or produced specifically for research purposes were subjected to patch clamp electrophysiological analysis under quasiphysiological conditions (Mansell et al. 2014). Control currents were obtained from healthy donor cells.
Results and discussion: Control outward K+ currents were robust and present in all cells recorded (reversal potential, Erev=−20 mV; 42 pA/pF at +68 mV). Infertile men were screened and two patients were identified to have different altered potassium conductances. Patient 1 had a depolarised membrane potential and was essentially devoid of outward K+ current (Erev=0 mV; 3 pA/pF at +68 mV). Patient 2 membrane potential was partially depolarised and exhibited an outward current that was notably less than control values but with a very similar burst pattern phenotype (Erev=−7 mV; 7 pA/pF at +68 mV) indicating a very low level of channel expression. A further 16 ICSI patients were found to have normal K+ conductance. Updated screening numbers will be presented. Patch clamp electrophysiology reveals rare K+ channel dysfunction in patient sperm and represents a powerful screening technique that permits uniquely quantifiable assessment of membrane potassium channel (dys)function in patient sperm.
02 - 04 Sep 2014
World Congress of Reproductive Biology