Probing human sperm metabolism using 13C-magnetic resonance spectroscopy

Area of Science:

• Biochemistry
• Metabolomics
• Reproductive Biology

Background:

• Human sperm energy production pathways, glycolysis and oxidative phosphorylation, are debated.
• Previous studies on sperm metabolism lacked detailed metabolic analysis.

Purpose of the Study:

• To investigate human sperm metabolism using 13C-Magnetic Resonance Spectroscopy (MRS).
• To determine substrate utilization by different human sperm populations.
• To assess the feasibility of using 13C-MRS for non-destructive sperm analysis.

Main Methods:

• Human sperm populations were isolated using density gradient centrifugation (DGC).
• Sperm were incubated with 13C-labelled substrates (glucose, fructose, pyruvate).
• Metabolism was analyzed via 1D 13C MRS, quantifying lactate and bicarbonate production.

Main Results:

• 13C-labelled glucose, fructose, and pyruvate were converted to lactate and bicarbonate.
• Vital and motile sperm from the 40/80% interface showed significantly higher glucose conversion to lactate compared to pellet sperm.
• Lactate production correlated with sperm concentration but not non-sperm cells.

Conclusions:

• 13C-MRS is a viable tool for assessing human sperm metabolism.
• Vital sperm demonstrate preferential glucose utilization, suggesting distinct metabolic strategies.
• This method holds potential for diagnosing and treating male infertility by identifying metabolic deficits.