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Defective function of membrane potential (psi) on sperm of infertile men
1Unidad de Investigación en Biología de la Reproducción, IMSS, México, DF Mexico.
Abstract:
Membrane potential across the plasma membrane (psi) of human sperm was determined by measuring the accumulation of triphenylmethylphosphonium (TPMP+). Washed sperm of fertile or infertile men were suspended, incubated in low-K+ and high-Na+ or high-K+ and low-Na+ medium, and allowed to take up the cation TPMP+ to a steady state (20 min at 37 degrees C). Under these conditions a psi of -75 +/- 6 mV was observed in sperm cells of fertile men, while in spermatozoa of idiopathic and asthenozoospermic infertile men, the psi was of 35 +/- 5 mV and 32 +/- 5 mV, respectively. Upon depolarization of the sperm membrane by K+, the transport system Na(+)-K+ in spermatozoa of idiopathic infertile men decreased 53 +/- 3.5%, while that in sperm cells asthenozoospermic men decreased 57 +/- 3% with respect to spermatozoa of fertile men. The results of these studies indicate their possible application to the diagnosis of male infertility.
Insights
Human sperm membrane potential (psi) differs significantly between fertile and infertile men. This finding suggests a new diagnostic method for male infertility using TPMP+ accumulation to measure psi.
Area of Science:
- Reproductive biology
- Cell physiology
Background:
- The plasma membrane potential (psi) is crucial for sperm function.
- Measuring psi in human sperm can provide insights into male fertility.
Purpose of the Study:
- To determine the membrane potential (psi) in human sperm from fertile and infertile men.
- To investigate the potential diagnostic application of psi measurements for male infertility.
Main Methods:
- Human sperm from fertile and infertile men were incubated in specific ionic media.
- Accumulation of the cation triphenylmethylphosphonium (TPMP+) was measured to determine steady-state psi.
- Sodium-potassium (Na(+)-K+) transport system activity was assessed upon membrane depolarization.
Main Results:
- Fertile men's sperm exhibited a psi of -75 +/- 6 mV.
- Infertile men (idiopathic and asthenozoospermic) showed significantly altered psi values of 35 +/- 5 mV and 32 +/- 5 mV, respectively.
- Na(+)-K+ transport decreased by over 50% in infertile sperm compared to fertile controls.
Conclusions:
- Human sperm membrane potential is a key differentiator between fertile and infertile individuals.
- TPMP+ accumulation offers a viable method for assessing sperm psi.
- These findings highlight the potential of psi measurement as a diagnostic tool for male infertility.