Sterility in Male Animals Induced by Injection of Chemical Agents into the Vas Deferens

Abstract

This study was undertaken to develop a simple non-surgical technic for achieving male sterility. The method induces obstruction in the vas deferens by injecting sclerosing chemical agents through the skin of the scrotum directly into the vas. Previous success in rats using 95% ethanol have been reported. This sutdy used 95% ethanol, 10% silver nitrate, 36% acetic acid, 3.6% formaldehyde, 3% sodium tetradecyl sulfate, 5% sodium morrhuate, 5% potassium permanganate, 3.6% formaldehyde in 90% ethanol, and for controls .9% sodium chloride. 25 or 50 mcl of the agent being tested was injected into each vas deferens of mature Sprague-Dawley rats. 2 weeks after treatment the rats were exposed to continuous mating. All of the rats treated with ethanol, silver nitrate, acetic acid, formaldehyde, and sodium tetradecyl sulfate have remained sterile for 8 months. 33% of those treated with potassium permanganate and 67% of those treated with sodium morrhuate have remained fertile. When the experiment was repeated in dogs using 95% ethanol, 10% silver nitrate, or 3.6% formaldehyde in 90% ethanol (100 or 500 mcl injected through the skin of the scrotum) the same obstructing sclerosis was found and a reduction in size of the vas was visible for approximately 2 cm. No sperm granulomas were found either grossly or microscopically. The method has not be used in humans but injections of methylene blue dye in alcohol have been made in several human autopsy specimens. The dye was contained within the sheath of the vas and penetrated the full thickness of the wall of the vas. The method is believed to be suitable for humans, would avoid post-surgical hemorrhage and infection, would require less equipment, and more rapid accomplishment and lower cost would follow if paramedical personnel could be taught the procudre in less developed countries for mass voluntary sterilizations. The results appear to be permanent. Surgical reversibility has not be determined.