Alterations in Sperm Motility and Hyperactivation (HA) Following in Vitro Methamphetamine (METH) Exposure

OBJECTIVE: Methamphetamine is an addictive central nervous system stimulant known to affect dopaminergic and serotonergic neurons. Meth use is a serious and growing health hazard, particularly since it increases risky sexual behavior. This portion of the study evaluated the in vitro effects of Meth on human sperm motility and HA. Separate experiments addressed semen quality in men who were using Meth, with or without HIV. DESIGN: In vitro addition of Meth to semen of healthy donors (n = 10) who did not use drugs. MATERIALS AND METHODS: Meth was diluted into F10 medium + 0.3% HSA (100μM, 10μM, 10nM, and 100pM) then added to the neat semen. Control aliquots had no Meth. The semen was washed, and swim-up portions were incubated at 37°C. Computer-assisted semen analysis (CASA) was used to track % motility, HA, velocity, and head movement after 2, 4, 6 and 24 hr of exposure to Meth. RESULTS: Results indicated that Meth had a biphasic effect (dose and time dependent) on sperm hyperactivation, expressed as % of control.Table 1100μM10μ10nM100pM2hr198.7120.8149.6175.94hr166.196.0149.0121.36hr162.381.9121.2148.824hr94.463.057.194.4Stimulation of HA after 2 hr was observed with 100uM, 10nM, and100 pM Meth. Both the 10 nM and 10 μM treatments induced significant inhibition of Hyperactivation after 24 hr (p < 0.001; p < 0.05). Sperm motility showed little change after Meth treatment. Open table in a new tab Stimulation of HA after 2 hr was observed with 100uM, 10nM, and100 pM Meth. Both the 10 nM and 10 μM treatments induced significant inhibition of Hyperactivation after 24 hr (p < 0.001; p < 0.05). Sperm motility showed little change after Meth treatment. CONCLUSIONS: In vitro Meth exposure induced significant (biphasic) effects on sperm hyperactivation. Early stimulation at 2 hr, followed by 24 hr inhibition was similar to nicotine effects on sperm function. Meth use is associated with more frequent sexual encounters and a higher incidence of HIV infection. As one reproductive endpoint, vigorous HA swimming is a key indicator of capacitation status and fertility potential. Ongoing studies will determine how Meth use changes semen quality, and whether newly addicted users have enhanced fertility potential.