F. M. Regazzi

Sperm maturation in dogs: sperm profile and enzymatic antioxidant status in ejaculated and epididymal spermatozoa.

Spermatozoa become more susceptible to the attack of reactive oxygen species during maturation. To avoid oxidative damage, the epididymis must provide the necessary antioxidant protection. The aim of this study was to compare the canine sperm profile and the enzymatic antioxidant status of the ejaculated fractions and samples collected from the different segments of the epididymis (caput, corpus and cauda). Five adult dogs were used, and after 1–3 weeks, subsequently to bilateral orchiectomy and epididymal storage, sperm samples were collected from the different segments of the epididymis. Samples were evaluated for conventional microscopy and computer‐assisted motility analysis: sperm plasma membrane permeability and the activity of the antioxidant enzymes catalase, glutathione peroxidase (GPx) and superoxide dismutase (SOD). Samples collected from the caput and corpus showed lower values for most of the motility variables evaluated, indicating different levels of immaturity. Catalase activity was observed only in ejaculated samples. Conversely, GPx activity was higher in the cauda epididymidis. Correlations were found between SOD and GPx and SOD and sperm motility in the epididymal cauda and corpus, highlighting the importance of the enzymes for the protection of spermatozoa during the transit along the epididymis.

Cortisol profile and clinical evaluation of canine neonates exposed antenatally to maternal corticosteroid treatment.

The effects of glucocorticoids on both foetal canine lung and endogenous serum cortisol concentration have not been clearly delineated. Therefore, we aimed to investigate whether maternal corticosteroid treatment can alter maternal and neonatal cortisol profile and improve neonatal vitality. We allocated six bitches of different breeds and their neonates into two groups: control group (CONT)--maternal administration of saline solution at 55 days post-ovulation (n = 3); and betamethasone group (BETA)--administration of a single dose of 0.5 mg/kg betamethasone (Celestone Soluspan(®) ) at 55 days post-ovulation (n = 3). Caesarean sections were scheduled for day 63 after ovulation. However, BETA group dams showed precocious signs of labour, and c-sections were performed at 58 days post-ovulation. Maternal and neonatal evaluations were performed periodically between betamethasone administration and birth, respectively. Neonates from both groups presented unsatisfactory (<5) Apgar score at birth. However, in spite of an earlier improvement on vitality found on CONT group and the premature delivery on BETA group, both groups showed acceptable Apgar score 120 min after birth. Neonatal cortisol concentrations were higher on CONT group compared to BETA group at birth. In addition, a gradual decrease on maternal cortisol concentrations was observed in the BETA group from treatment until parturition. These findings suggest that despite the down-regulation on the hypothalamic-pituitary-adrenal axis and the induction of premature delivery, betamethasone treatment was able to provide similar vitality when compared to the untreated neonates born at term.

Hemodynamics of the uterine and umbilical arteries during the perinatal period in ewes

Examining feto-maternal blood flow is extremely important for accurate prenatal control and predicting adverse conditions during puerperium. We aimed to analyze blood flow of uterine artery (UA) and umbilical artery (UMA) from and subsequent to mid-gestation, lambing and postpartum of 15 ewes, subjected to lambing induction with aglepristone. Hemodynamic variables, diameter and blood flow of UA and UMA were determined by Doppler and B-mode ultrasonography at 60, 90 and 120 days of pregnancy, at 12 h before, 12 h after first aglepristone injection and 12 h after induction and days 1, 3, 5, 7, 15 and 30 after lambing. The UMA peak systolic:diastolic velocity (S/D), resistance index (RI) and pulsatility index (PI) decreased from mid-pregnancy until 120 d, whereas peak systolic velocity (PSV), end diastolic velocity (EDV) and time average maximum velocity (TAMAX) increased towards 120 d. The UMA RI additionally decreased at 12 h after lambing induction. The UMA diameter and volume increased from mid-gestation until 12 h before lambing induction. UA PSV and TAMAX increased from 60 until 90 days of pregnancy, while EDV, PSV and TAMAX decreased soon after parturition, with a further reduction at 7 days. The UA diameter and volume decreased during postpartum, stabilizing by 15 days after parturition. In conclusion, pregnancy is marked by progressive increase in uterine and umbilical blood flow, while lambing acutely diminishes umbilical vascular resistance, suggesting lack of progesterone influence on vasodilation. Conversely, puerperium is characterized by reduction in uterine blood supply mostly within the first 2 weeks of postpartum in sheep.

Perfil de proteínas plasmáticas em cadelas gestantes e não gestantes

O estudo das interacoes orgânicas da gestacao e as mudancas fisiologicas que estao ocorrendo nesta fase sao de extrema importância para a avaliacao clinica da femea gestante ou para estabelecer o diagnostico de processos patologicos em andamento. O objetivo do presente estudo foi comparar o perfil das diversas proteinas sanguineas (fracoes proteicas do soro - albumina, a1, a2, b, g globulinas e proteina total) durante o periodo gestacional e no diestro em cadelas. Foram utilizadas 40 femeas caninas da raca Dogue Alemao, em idade variando entre 2 a 7 anos, clinicamente saudaveis. Os animais foram separados em dois grupos, denominados Grupo nao gestante (NG) e Grupo gestante (G), constituidos por 20 femeas em diestro e 20 femeas gestantes, respectivamente. Preconizou-se colheita de sangue semanalmente de cada animal durante 9 semanas. Nas femeas do grupo NG, as amostras foram colhidas a partir do inicio do diestro, ate a deteccao do inicio do anestro; no grupo G, as amostras foram colhidas do inicio do diestro ate o momento da paricao. A partir do soro sanguineo, foram determinadas as concentracoes de proteina total, albumina, a1, a2, b e g globulinas. Nao houve diferenca significativa quanto aos resultados de proteina serica total entre a 1a e 6a semanas de gestacao e diestro, havendo decrescimo gradual em ambos grupos. Ja ao final da gestacao (entre a 7a e 9a semanas), houve acrescimo significativo dos valores de proteina total, sugerindo acao anabolica. Os niveis de albumina sofreram queda da 1a a 9a semana, tanto no grupo gestante, como nao-gestante, com diferenca estatistica entre os dois grupos na 7a, 8a e 9a semanas. As concentracoes de α1 globulina nas femeas gestantes sofreram acrescimo significativo a partir da 2a semana, contudo, diferenca estatistica entre os grupos NG e G ocorreu somente na 8a e 9a semanas, coincidindo com a fase de preparacao a paricao. Houve aumento no perfil de α2 globulina entre a 2a e 3a semanas de gestacao, porem tais valores nao diferiram das femeas em diestro. Diferenca significativa de α2 globulina foi observada apenas durante a 4a, 5a, 6a, 8a e 9a semanas entre os dois grupos avaliados. As concentracoes sericas de β globulina nas cadelas nao-gestantes foi superior as das femeas gestantes durante a 2a, 4a e 7a semanas. Durante o primeiro terco da gestacao (1a a 3a semana), foi observado queda dos valores de γ globulina, coincidente ao periodo pre implantacional e durante a formacao dos sitios de implantacao. Entre a 8a e 9a semanas de gestacao, houve acrescimo significativo de γ globulina, possivelmente consequente ao aumento da producao de imunoglobulinas direcionadas a glândula mamaria, como constituinte do colostro. Em conclusao, as proteinas alteram-se de forma evidente durante o periodo de gestacao. Foi possivel inferir diferencas nas funcoes biologicas das proteinas sanguineas em cadelas gestantes e nao gestantes. As proteinas determinadas estao envolvidas com o estimulo inflamatorio durante a gestacao, alem dos mecanismos de regulacao hormonal e preparacao do organismo materno a lactacao.

The Oxidative Stress, Antioxidant Profile and Acid–base Status in Preterm and Term Canine Neonates

During the initiation of neonatal pulmonary respiration, there is an exponential increase in reactive oxygen species that must be scavenged by antioxidant defences. However, neonate and preterm newborns are known to possess immature antioxidant mechanisms to neutralize these toxic effects. The purposes of this study were to compare the development of antioxidant system between preterm and term canine neonates and to evaluate the magnitude of acid-base balance during the initial 4 h of life. A prospective study was conducted involving 18 neonatal puppies assigned to Term Group (63 days of gestation; n = 5), Preterm-57 Group (57 days of gestation; n = 8) and Preterm-55 Group (55 days of gestation; n = 5). Neonates were physically examined through Apgar score and venous haemogasometry within 5 min, 2 and 4 h after birth. No difference on amniotic fluid and serum superoxide dismutase (SOD), glutathione peroxidase (GPx) and the marker of oxidative stress (thiobarbituric acid reactive substances; TBARS) was verified. Irrespective of prematurity, all neonates presented low vitality, hypothermia, acidosis, hypoxaemia and hypercapnia at birth. However, term puppies clinically evolved more rapidly than preterm newborns. During the course of the study, premature neonates presented more severe complications, such as prolonged hypoxaemia and even death. In conclusion, premature puppies have no signs of immature enzymatic mechanisms for controlling oxidative stress, although SOD and GPx may participate in achieving acid-base balance. Aside from initial unremarkable symptoms, premature puppies should be carefully followed up, as they are at high risk of succumbing to odds of prematurity.