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The cryopreservation of testicular tissue is presented as the only alternative for the preservation of genetic material from prepubertal animals. However, this biotechnology is still being tested. The objective of this study was to evaluate the effect of different associations of cryoprotectants and the potential of cell proliferation after vitrification of testicular tissue of prepubertal cats. Five testicular pairs from five prepubertal cats were used, and each pair was divided into four fragments. Of these, one fragment composed of the control group (CG) and the rest were distributed in experimental groups according to the associations of cryoprotectants to be tested (dimethyl sulphoxide (DMSO)/glycerol (GLY); ethylene glycol (EG)/GLY) or DMSO/EG) in a final cryoprotectant concentration of 5.6 m. The fragments were submitted to vitrification, and after one week, fragments were heated and processed for histomorphological evaluation and quantification of nucleolar organizer regions (NORs). DMSO/GLY did not differ from CG and was superior to the other vitrified groups, as to cell separation and degree of shrinkage of the basal membrane. Concerning cell differentiation, visibility of the nucleus and nuclear condensation, all the vitrified groups were inferior to CG; however, DMSO/EG was inferior to DMSO/GLY and EG/GLY, which did not differ among themselves. CG was superior to all groups in quantification of NORs. DMSO/EG was inferior to all others, and there was no difference between DMSO/GLY and EG/GLY. The association DMSO/GLY presented the best preservation of tissue integrity and potential of cell proliferation after vitrification of the testicular tissue of prepubertal cats., (© 2016 Blackwell Verlag GmbH.)

The reproductive potential of male animals is commonly evaluated using a breeding soundness examination incorporating B-mode ultrasound examination of the testes and recently Doppler ultrasound examination of the testicular arteries. These techniques may detect testicular normality or pathology, and while some measured parameters are associated with semen quality at the time of ultrasound examination, few studies have investigated the relationship with future semen quality. We hypothesized that B-mode and Doppler ultrasound measurements would correlate with future semen quality. Within two studies, we investigated the relationship between ultrasound measured testicular volume, testicular echogenicity, testicular homogeneity, subjective assessment of the testicular parenchyma, testicular artery resistance index, and pulsatility index with subsequent semen quality. Fifty-five normal fertile dogs of which 29 had stable semen quality and 26 had a subsequent decline in semen quality were examined during a 6-month period commencing 62 days after the ultrasound examination. Statistical analysis showed that no ultrasound parameters were predictive of future total sperm output or percentage live normal sperm. However, mean testicular echogenicity was positively related to future sperm motility (t = 2.202, p = .039). We conclude that quantitative ultrasound assessment of the appearance of the testicular parenchyma has potential for the evaluation of future semen quality in dogs., (© 2016 Blackwell Verlag GmbH.)