title: Biophysical mechanism-mediated time-dependent effect on sperm of human and monkey vas implanted polyelectrolyte contraceptive.
abstract: OBJECTIVE
  To determine the short and long-term morphological effects on sperm as induced by intra-vas alteration of pH and electrical charge.
  
  
  METHODS
  Desired biophysical influences were obtained by injection of reversible inhibition of sperm under guidance (RISUG) into the lumen of the vas deferens of human subjects and the monkey. RISUG is a polyelectrolyte hydrogel complex of styrene maleic anhydride (SMA) and dimethyl sulfoxide (DMSO) which generates an electrostatic charge and also lowers in a near space of pH domain. The morphology of sperm was examined by light microscopy, scanning and transmission electron microscopy. Human study enabled semen collection by masturbation as early as 3 h after injection and studies extended up to 6 months. In the monkey, on vas excision after RISUG implantation, sperm characteristics were examined in serial sections.
  
  
  RESULTS
  Semenology in clinical studies and histological data of the monkey showed a time-sequenced sperm plasma membrane, tail mitochondria and nuclear decondensation alterations in sperm structural components, which beared marked similarity to changes in the sperm head and tail during capacitation and entry into the ovum.
  
  
  CONCLUSIONS
  The findings provide a means of causing such changes in the sperm that inhibit the fertilizing ability before the nucleus is affected. Therefore achieving non-obstructive vas-based contraception, without genotoxic or teratogenic effects caused by infertile sperm passing into the semen, is feasible.
authors.affiliation: School of Medical Science and Technology, Indian Institute of Technology, Kharagpur 721302, India. guha_sk@yahoo.com
authors.forename: Sujoy K
authors.initials: SK
authors.lastname: Guha
mesh_terms: D000328:Adult; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D003272:Contraceptive Agents, Male / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D008298:Maleates / Q000494:pharmacology*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D011091:Polyesters; D011137:Polystyrenes; D013094:Spermatozoa / Q000187:drug effects* / Q000648:ultrastructure; D013343:Styrenes / Q000494:pharmacology*; D014649:Vas Deferens
chemical_list: D003272:Contraceptive Agents, Male; D008298:Maleates; D011091:Polyesters; D011137:Polystyrenes; D013343:Styrenes; C440495:contraceptive agent, RISUG; D004121:Dimethyl Sulfoxide