962 resultados para Semen cryopreservation


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Pós-graduação em Medicina Veterinária - FMVZ

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Background: Intrauterine insemination (IUI) is widely used to treat infertility, and its adequate indication is important to obtain good pregnancy rates. To assess which couples could benefit from IUI, this study aimed to evaluate whether sperm motility using a discontinuous gradient of different densities and incubation in CO2 in normospermic individuals is able to predict pregnancy.Methods: A total of 175 couples underwent 175 IUI cycles. The inclusion criteria for women were as follows: 35 years old or younger (age range: from 27 to 35 years) with normal fallopian tubes; endometriosis grades I-II; unexplained infertility; nonhyperandrogenic ovulatory dysfunction. Men with normal seminal parameters were also included. All patients underwent ovarian stimulation with clomiphene citrate and human hMG or r-FSH. When one or (at most) three follicles measuring 18 to 20 mm were observed, hCG (5000 UI) or r-hCG (250 mcg) was administered and IUI performed 36-40 h after hCG. Sperm processing was performed using a discontinuous concentration gradient. A 20 microliters aliquot was incubated for 24 h at 37 degrees C in 5% CO2 following a total progressive motility analysis. The Mann-Whitney and Chi-square tests, as well as a ROC curve were used to determine the cutoff value for motility.Results: Of the 175 couples, 52 (in 52 IUI cycles) achieved clinical pregnancies (CP rate per cycle: 29.7%). The analysis of age, duration and causes of infertility did not indicate any statistical significance between pregnancy and no pregnancy groups, similar to the results for total sperm count and morphology analyses, excluding progressive motility (p < 0.0001). The comparison of progressive motility after processing and 24 h after incubation between these two groups indicated that progressive motility 24 h after incubation was higher in the pregnancy group. The analysis of the progressive motility of the pregnancy group after processing and 24 h after incubation has not shown any motility difference at 24 h after incubation; additionally, in couples who did not obtain pregnancy, there was a statistically significant decrease in progressive motility 24 h after incubation (p < 0.0001). The ROC curve analysis generated a cutoff value of 56.5% for progressive motility at 24 h after incubation and this cutoff value produced 96.1% sensitivity, 92.7% specificity, 84.7% positive predictive value and 98.3% negative predictive value.Conclusions: We concluded that the sperm motility of normospermic individuals 24 h after incubation at 37 degrees C in 5% CO2, with a cutoff value of 56.5%, is predictive of IUI success.

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The major challenge for a greater dissemination of in vitro produced (IVP) bovine embryos is to improve embryonic survival after cryopreservation. The involvement of embryonic lipids on this issue is well documented. However, it has been recognized that not only the amount of lipids that affects embryo cryotolerance, but the embryo survival capacity after cryopreservation is a rather multifactorial event. In this review, some strategies to improve embryonic lipid composition and postcryopreservation survival by modifying the embryos themselves to make them more cryopreservable are overviewed. The use of semi-defined and defined serum-free culture media, the addition of some chemicals in the culture media to modify embryo lipid composition, and the modulation of embryo cell membrane fluidity by cholesterol or unsaturated fatty acids added to the culture media and oocyte/embryo donor nutritional management with a diet enriched in polyunsaturated fatty acids, were described as alternatives for the improvement of IVP embryo survival after cryopreservation.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Two studies were conducted to understand sperm cryosensitivity in an endangered equid, the Przewalski's horse (Equus ferns przewalski), while testing the cryoprotectant ability of formamides. The first assessed the toxicity of permeating cryoprotectants (glycerol, methylformamide IMF] and dimethylformamide [DMF]) to Przewalski's horse spermatozoa during liquid storage at 4 C. The second examined the comparative influence of three diluents (with or without formamides) on cryosurvival of sperm from the Przewalski's versus domestic horse. When Przewalski's horse spermatozoa were incubated at 4 C in INRA 96 with differing concentrations of glycerol, MF or DMF or a combination of these amides, cells tolerated all but the highest concentration (10% v/v) of MF alone or in combination with DMF, both of which decreased (P < 0.05) motility traits. There was no effect of cryoprotectants on sperm acrosomal integrity. In the cryosurvival study, average sperm motility and proportion of cells with intact acrosomes in fresh ejaculates were similar (P> 0.05) between the Przewalski's (67%, 84%, respectively) and domestic (66%, 76%) horse donors. Sperm from both species were diluted in lactose-EDTA-glycerol (EQ), Botu-Crio (BOTU; a proprietary product containing glycerol and MF) or SM (INRA 96 plus 2% [v/v] egg yolk and 2.5% [v/v] MF and DMF) and then frozen over liquid nitrogen vapor. After thawing, the highest values recovered for total and progressive sperm motility, acrosomal integrity and mitochondria] membrane potential were 42.4%, 21.8%, 88.7% and 25.4 CN (CN = mean JC-1 fluorescence intensity/cell on a channel number scale), respectively, in the Przewalski's and 49.3%, 24.6%, 88.9% and 25.8 CN, respectively, in the domestic horse. Although sperm progressive motility and acrosome integrity did not differ (P> 0.05) among treatments across species, mitochondrial membrane potential was higher (P< 0.05) in both species using EQ compared to BOTU or SM media. Additionally, Przewalski's stallion sperm expressed higher (P < 0.05) post-thaw total motility in BOTU and SM compared to EQ whereas there were no differences among freezing diluents in the domestic horse. In summary, Przewalski's stallion sperm benefit from exposure to either MF or DMF as an alternative cryoprotectant to glycerol. Overt sperm quality appears similar between the Przewalski's and domestic horse, although the total motility of cells from the former appears more sensitive to certain freezing diluents. Nonetheless, post-thaw motility and acrosomal integrity values for Przewalski's horse spermatozoa mimic findings in the domestic horse in the presence of INRA 96 supplemented with 2% (v/v) egg yolk and a combined 2.5% concentration of MF and DMF. Published by Elsevier Inc.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The process of spermatic division and differentiation (spermatogenesis) occurs with intratesticular temperature lower that the corporal temperature and for that is essential that the testicular thermoregulation mechanism occurs properly. For evaluation of the scrotal surface temperature can be used the infrared thermography or testicular sensors, besides that, can be evaluated the blood flux in the spermatic cord through the Doppler ultrasonography. Thus, the aim of this study is to analyze the testicular thermoregulation in adult buffaloes through scrotal thermography and Doppler ultrasound of testicular artery and verify its effect on sperm quality. For that were used seven healthy buffaloes, with age of 3 and 4 years, of the Murrah breed. The animals were subjected to 3 semen collections using artificial vagina, with one day of interval. In addiction, the retal temperature measurement (RT) with dry bulb thermometer, the measurement of scrotal surface temperature (SST) and body surface temperature (BST) through infrared thermography and the pulsatility (PI) and resistivity (RI) index of testicular artery by Doppler ultrasonography, were performed using 2 distinct moments: animals previously placed to shade (M1) and animals subjected to 4 hours of sun (M2). All parameters were compared by T test and the correlations were performed by Pearson test using the In Stat Graph Pad 3 (R) program. The significant level considered was 5%. There was an increase (p<0,05) of RT, SST, SNT and RI in M2. increasing trend was observed (0,05>p>0,01) PI and RI between M1 and M2. There was a low correlation between SST and semen quality. The results of this study allow us to conclude that adult buffaloes have low ability to perform body and testicular thermoregulation in situations of enviromental heat stress. However, this low capacity of testicular temperature maintenance demonstrated no correlation with the sperm kinetic parameters and sperm morphological defects in buffalo spermatozoa.

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Ipomoea carnea is a toxic plant in Brazil and other tropical countries that often poisons livestock; its primary toxin is swainsonine. Some substances that interact with the endocrine system have been called endocrine disruptors (EDs). Considering swainsonine's mode of action, it is feasible to hypothesize that this compound could act as an ED. Bisphenol A (BPA), an estrogen-mimic, is considered a classical ED in rodents. This study aimed to evaluate the possible ED actions of I. cameo and BPA in male goats. Seventeen adult male goats were divided into three homogeneous groups: control (C, n = 5); IC (n = 6, received 5.0 g/kg body weight of freshly harvested I. cornea per day), and BPA (n = 6, received 25.0 mg/kg body weight of BPA per day). The experimental period was 120 days. During the experiment, blood samples were collected at 0, 30, 60, 90 and 120 days for biochemical and hormonal evaluations. On the same days, semen samples were collected for andrological evaluation, and scrotal circumference and testicular consistency were determined. The males were castrated on day 121, and fragments of testicle and epididymis were collected for histopathological evaluation. A decrease in serum T3 and T4 was observed in the IC group as well as an increase in the number of sperm with morphological alterations. In the BPA group, reduced serum 14 and a decreased percentage of sperm with plasma membrane integrates were observed. A histopathological examination revealed the vacuolar degeneration of Sertoli cells and areas of laminar patterns of calcium deposits in the IC group and vacuolar degeneration in the rete testis in the BPA group. These results indicate that both I. cameo and BPA are potential EDs in goats. This study emphasized the susceptibility of livestock to ED actions. We also demonstrated the action of I. cameo acting as EDs in the endocrine and reproductive systems. (C) 2014 Elsevier B.V. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The aim of this study was to evaluate the effects of breed and season on semen quality parameters of zebu bulls. Data (1,632 registers) of semen production from Gir (n = 4) and Nelore (n = 15) bulls were collected between October 2005 and November 2009. The ejaculates were collected twice a week during various seasons (summer, fall, winter, and spring) and evaluated for the following semen parameters: ejaculate volume, sperm concentration, sperm motility, forward progressive motility (FPM), and sperm morphology. Factor analysis was used to determine the relationship among variables. The effect of breed (Gir and Nelore) and season and their cross effect on each parameter and extracted factor were tested using ANOVA. A negative correlation (P < 0.05) was observed between FPM and proximal droplet, as well as with abnormal loose head, abnormal small head, pouch formation, abnormal mid-peace, and strongly folded tail. Gir bull sperm showed more major defects, detached acrosome, and minor FPM (P < 0.01), whereas Nelore bulls showed a higher number of sperm with normally loose head.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)