ABSTRACT
BACKGROUND: Proximal cytoplasmic droplets (PCDs), a remnant of germ cell cytoplasm, are common non-specific morphological defects in bovine semen. This study evaluated the effect of higher percentages of PCDs on the quality of frozen-thawed bovine semen, embryo production and early embryo development. METHODS: Three ejaculates from each of five (group 1: PCD ≤ 1%, control) and eight adult Bos indicus bulls (group 2: PCD ≥ 24%) were analysed. Semen samples were examined for: post-thaw motility, vigour of movement, concentration, sperm morphology, slow thermoresistance test (STT), membrane integrity, acrosome status, mitochondrial function using fluorescent probes association (FITC-PSA, PI and JC-1) and sperm chromatin integrity using acridine orange assay. Two bulls from group 2, with 28.5% and 48.5% PCD, respectively, and three bulls from the control group, each with 0% PCD, were selected for IVF (in vitro fertilisation). RESULTS: Semen analyses revealed a significant correlation (P < 0.01) between increased rates of PCD and sperm quality traits. Nevertheless, no differences were observed in sperm motility and vigour either before or after the STT or in the percentage of intact acrosomes (analysed by differential interference contrast microscopy (DIC) after STT), but membrane integrity, acrosome status (evaluated with FITC-PSA staining method after thawing) and mitochondrial function were reduced, when compared with group 1 (P < 0.05). The higher incidence of PCD was positively correlated to chromatin damage, especially after three hours of incubation at 37°C. IVF showed similar results for bull C2 (group 1, control) and bull P2 (group 2, group with higher PCDs). CONCLUSION: Higher PCD levels influenced spermatozoa quality traits. IVF and embryo development data showed that cleavage, blastocyst formation and blastocyst hatching may have been influenced by the interaction of morphology traits and individual bull effects.
Subject(s)
Cattle/physiology , Cryopreservation/veterinary , Embryonic Development , Semen Preservation/veterinary , Spermatozoa/physiology , Animals , Brazil , Cattle/genetics , Cryopreservation/methods , Fertilization in Vitro/veterinary , Male , Semen Preservation/methods , Sperm Motility , Spermatozoa/cytologyABSTRACT
Nesta pesquisa foram obtidos dados histológicos e morfométricos comparativos sobre os testículos de gatos, pós-orquiectomia, divididos em dois grupos: Grupo 1, gatos com até 1 ano de idade e Grupo 2, animais acima de 1 ano. Verificou-se que: (1) aos 4 meses de idade os túbulos seminíferos apresentaram-se pouco desenvolvidos e com ausência de luz, epitélio seminífero baixo, células de Sertoli indiferenciadas e tecido intersticial escasso; (2) aos 5 meses os túbulos seminíferos começaram a se diferenciar com aumento do diâmetro e luz tubulares e as demais estruturas permaneceram semelhantes à observação anterior; (3) aos 6-7 meses ocorreu o início da espermatogênese e espermiogênese; as células de Leydig apareceram maiores, poliédricas com citoplasma vacuolizado e núcleo claro, e tecido intersticial esparso com poucos vasos sangüíneos; (4) os animais com 1 ano de idade apresentaram morfologia testicular igual à do animal adulto, com túbulos seminíferos de maior diâmetro, epitélio germinativo alto e luz tubular pequena, as células de Leydig aparecendo poliédricas, com dimensões variadas, citoplasma vacuolizado, núcleo claro e nucléolo evidente, e espaço intertubular seminífero variado com vasos sanguíneos, predominantemente evidentes; (5) no Grupo 1 o diâmetro médio dos túbulos seminíferos foi de 160,58µm e no Grupo 2 foi de 185,94µm, sendo os valores médios significantes entre si; (6) a altura média do epitélio seminífero foi de 49,51µm para o Grupo 1 e de 63,29µm para o Grupo 2, estaticamente significantes; (7) os maiores valores mensurados foram obtidos para os gatos do Grupo 2, por serem gatos adultos e portanto com os órgãos reprodutores funcionais.
This paper deals with a comparative histologic and morphometric study of the testes of domestic cats distributed into two groups: Group 1, cats until 1 year of age, and Group 2, cats over 1 year. It was found that: (1) at 4 months of age the seminiferous tubules were poorly developed, appeared as seminiferous cords without lumen, lined by a low epithelium, and showed undifferentiated Sertoli cells and scarce interstitial tissue; (2) at 5 months the seminiferous tubules began to differentiate with increase in tubular diameter and lumen, the other tubular structures remaining similar to those previous referred; (3) at 6 and 7 months of age spermatocytogenesis began to appear, Leydig cells were large, polyhedral in shape, with vacuolated cytoplasm and clear nuclei, resting on a sparse interstitial tissue with few blood vessels; (4) 1-year-old cats showed testicular histological features of an adult animal, had seminiferous tubules of large diameter and high seminiferous epithelium with small lumen, and Leydig cells of different sizes, with polyhedral shape, vacuolated cytoplasm, clear nuclei and evident nucleoli resting in a sparse interstitial tissue with some blood vessels; (5) in Group 1 the average diameter of the seminiferous tubules was 160.58µm, and 185.94µm in Group 2; (6) the height of the seminiferous epithelium was 49.51µm for Group 1 and 63.29µm for Group 2; (7) the largest measures of the analyzed parameters were found in animals of Group 2, with functional reproductive organs.
