Criopreservação de tecido testicular de cães : avaliação histológica e ultraestrutural

Abstract

Canids are part of the large number of endangered species. The survival of these species depends on the conservation of existing biodiversity. The use of gamete preservation techniques associated with reproductive technologies such as artificial insemination (AI), in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) were developed to help propagate and preserve the genetic potential of canídeos.A testicular tissue cryopreservation might be a method used when ejaculate freezing techniques is not possible. This work set in two experimentos congelamento and vitrificaçãoin vitro, comparing different cryoprotectants (glycerol, dimetisufóxido (DMSO) and trehalose) in testicular tissue of domestic dogs (Canis familiaris). Fragments of 9 adult dogs testes were subjected to a cooling with 4 cryopreservation protocols: slow freezing with glycerol, dimethylsulfoxide (DMSO) or solid surface vitrification using glycerol or DMSO. Fragments of 3mm testicular parenchyma were separated into groups: control, subjected to slow freezing and vitrification. Histological evaluations of the fragments were performed before, after freezing and thawing by light and electron microscopy. Based on morphology and ultrastructure, the testicular tissue of slow freezing, there was no difference between the cryoprotectants. Among the vitrified groups, exposure to DMSO produced a greater structural integrity and architecture when compared to the glycerol group. Comparison of slow freezing and vitrification have shown that vitrification samples revealed more area consisting of tubular compartment, tubular lumen, seminiferous epithelium and conserved membrane. Furthermore, the intertubular compartment Leydig cells showed normal morphology and had characteristics typical of steroidogenic cells. From the results, it was concluded that vitrification DMSO is the most effective method for criopresevar testicular tissue of adult dogs, and can be used as a routine procedure.