Efectos de la inmunización contra GnRH sobre la estructura y función testicular en perros adultos

Effects of immunization against GnRH in the structure and function of testicles in adult dogs. The use of GnRH and its analogues for reversible immunological castration in mammals offers great possibilities to achieve successful fertility control in domestic animals. The goal of this work was to evaluate the biological effect of GnRHm1-TT, a synthetic vaccine formulation as an immunogen, on the reproductive organs and semen quality of adult male Beagle dogs. Eight dogs of 16-17 years of age and 9-13 kg, were used. The sample was distributed at random in two groups of four animals each. One group was placebo, and the other received two doses of 1 mg of the formulation with an eight-week interval and equivalent to 0.8 mg of GnRHm1 per animal. Respectively, complete and incomplete Freund adjuvants were used on the first and second immunizations. The experiment lasted 16 weeks. In the doses and scheme used, peptide GnRHm1-TT induced structural and functional changes in testicles and epididymides, probably due to the neutralizing capacity of anti GnRH antibodies on endogenous GnRH. At the end of the experiment it was concluded that the ejaculates from dogs corresponded to one animal ready for reproduction, another not ready, and the other two uncertain. In the three last cases it was caused by low concentration of viable spermatozoa and high percentage of pathological spermatozoa; however, all placebo animals were up for reproduction. The results achieved allow us to suggest the possibility of trying other schemes and doses with this peptide to achieve effective inhibition of the reproductive capacity of dogs and other adult mammal species.