Effects of delta-9-tetrahydrocannabinol, the primary psychoactive cannabinoid in marijuana, on human sperm function in vitro

Objective: To investigate effects of delta-9-tetrahydrocannabinol (THC) on human sperm function in vitro. Design: Laboratory analysis of sperm motility after exposure to THC using computer-assisted semen analysis and acrosome reaction by fluoroscein isothiocyanate-labeled peanut agglutinin staining. Setting: An assisted reproductive technology unit. Patient(s): Seventy-eight male patients. Intervention(s): Sperm were divided into 90% (the best fertilizing potential used in assisted conception) and 45% (the poorer subpopulation) fractions by density centrifugation and incubated with THC at concentrations equivalent to therapeutic (0.032 mu M) and recreational (0.32 and 4.8 mu M) plasma levels at 37 degrees C for 3 h. Main Outcome Measure(s): Sperm motility and spontaneous and induced acrosome reactions. Result(s): Percentage progressive motility was decreased dose dependently in the 90% fraction (by 2%-21%; P <.05; P <.001). The 45% fraction showed a greater decrease in percentage progressive motility (by 28% at 0.032 mu M; 56% at 4.8 mu M; P=.004 and P=.01 res). Straight line velocity and the average path velocity also were reduced (by 10%, in the 90% LAYER) in both fractions. Spontaneous acrosome reactions were reduced in the 90% (17% at 0.032 mu M, 35% at 4.8 mu M P=.004 and P <.001 resp) and more markedly in the 45% fractions (17%-35%; P <.001). When the acrosome reaction was artificiafly induced (90% fraction) by A23187, THC (4.8 mu M) resulted in a 57% inhibition (P <.001). Conclusion(S): The use of THC as a recreational drug may adversely affect male fertility.