The rate of forward motility increased from 3.6% to
16.8% (Figure 1a). The change in motility by H2 treatment
was higher than or similar to results previously
reported, e.g., 17.95% to 25.1% for treatment with
platelet-activating factor [27] and a 21% increase for exogenous
pyruvate treatment [28]. Because the increase
of forward motility was observed within only 30 min, H2
treatment may stimulate cell signaling and activate mitochondria,
but not transcription and translation in sperm.
However, it remains to be elucidated whether the stimulatory
effects are dependent on a property of H2 as a reductant.
Furthermore, H2, but not N2, stimulated sperm
motility, indicating that the effect of H2 did not rely on
mechanical stimuli.