THE IN-VITRO EFFECTS OF NICOTINE AND COTININE ON SPERM MOTILITY

Swim-up spermatozoa from the seminal samples of nonsmokers, usually no t exposed to passive smoking, were treated in vitro with nicotine (NIC ) and cotinine (COT) at the average levels found in smokers' seminal p lasma and at levels 500 times higher than this average, This was done to evaluate the action of these drugs on sperm motility, Each sample w as allowed to swim up in Tyrode's solution with or without the drug; t he study was carried out at time 0 and +1, +2, +4, +8 and +24 h of inc ubation, using a light microscope and a CASA system (experiment 1), In addition, the direct action of smoke on spermatozoa was studied using aspirated cigarette smoke (experiment 2), Kinetic parameters were the n measured at 30 min, 45 min and 60 min starting from the last smoke i njection, The first experiment showed that MC and COT at average level s did not produce statistically significant variations of the kinetic parameters studied up to 24 h, However, the much higher concentration significantly altered all the kinetic variables in relation to the tim e of incubation, The second experiment with smoke in toto demonstrated a sharp reduction in all the sperm kinetic parameters, This reduction was seen after 30 min exposure to smoke and increased progressively u ntil almost complete immotility at 1 h of exposure, These results sugg est that NIC and COT are not responsible for the harmful effects of ci garette smoke on sperm kinetic parameters reported in the literature.