Support by FAPESP- Process: 06/03468-0.

Visceral leishmaniasis is determined by an intracellular protozoa belonging to the Leishmania donovani complex. The dog is admittedly the most important reservoir for visceral leishmaniasis and in Brazil the Leishmania chagasi is described. Recent studies have described lesions associated to the genital system. The parasite was detected in epididymis, testes, prepuce and glans penis tissues as well as in semen samples. The goal of the present study was evaluating spermatic changes associated with the natural infection in dogs by Leishmania sp. During eight consecutive weeks, ejaculates of six seronegative and six seropositive dogs were evaluated. The samples, 96 in total, were collected once a week by manual stimulation, and analyzed as to volume, concentration, motility, vigor, sperm morphology, chromatin integrity accessed by acridine orange stain, simultaneous evaluation of the plasmatic membrane integrity, acrosome status and mitochondrial potential through fluorescent probes (FITC-PSA, PI and JC-1). At the same time, the total proteins of the seminal plasma and blood plasma were measured. At the end of the trial, positive animals were submitted to euthanasia. The visceral Leishmaniasis caused an increase of major and minor defects in spermatozoa of animals affected by moderate to severe stages of the disease. In more advanced stages of the illness, the acrosomal and plasmatic membrane integrity was adversely affected. It was not possible to establish a pattern referring the evaluation of the mitochondrial potential using the mitochondrial probe 5,5',6,6'-tetrachlorine-1,1,3,3'-tetraethylbenzimidazolyl-carbocyanine iodide (JC-1). The incidence of morphological changes and the illness itself did not promote an increase of injuries to the chromatin. All animals with Leishmaniasis presented hyperproteinemia of the seminal plasma. The results of the present work proved that the seropositive animals, in a moderate or severe degree, presented spermatological changes, becoming susceptible to reproductive damage. In addition, a constant and outstanding datum was the hyperproteinemia observed in the seminal plasma, proving to be something reliable and interesting for new researches.