Monoclonal antibodies against human CD34 antigens do not cross-react with ovine umbilical cord blood cells

CD34 is a cell surface glycoprotein expressed by hematopoietic progenitors and endothelial cells. It is widely used in the clinic for isolation of human hematopoietic stem cells. In recent years large animals are gaining increasing importance in biomedical research for the study and therapy of human diseases. Sheep has proved to be an useful experimental model for preclinical trials in transplantation procedures. Unfortunately, the lack of specie-specific monoclonal antibodies (MABS) recognizing hemopoietic progenitor cells hampers the use of this animal in experimental hematology. The aim of this paper was to determine whether commercial monoclonal antibodies specific for human CD34 molecule could cross-react with hematopoietic progenitor cells (HPC) present in sheep umbilical cord blood (UCB). Six anti-human CD34 MABS, recognizing the three different epitope classes, were tested in flow cytometry on purified mononuclear cells (MNC) isolated from cord blood of both species. None of the MABS used in this trial seemed to be able to identify HPC from sheep UCB. These data suggest that the panel of monoclonal antibodies used for cross reactivity detection has to be expanded with recently produced reagents. Further studies should be directed towards the production of ovine specific anti CD34 MABS

Testicular degeneration and infertility following arbovirus infection

Arboviruses can cause a variety of clinical signs including febrile illness, arthritis, encephalitis and hemorrhagic fever. The recent Zika epidemic highlighted the possibility that arboviruses may also negatively affect the male reproductive tract. In this study, we focused on bluetongue virus (BTV), the causative agent of bluetongue and one of the major arboviruses of ruminants. We show that rams that recovered from bluetongue displayed signs of testicular degeneration and azoospermia up to 100 days after the initial infection. Importantly, testicular degeneration was induced in rams experimentally infected with either a high (BTV-1IT2006) or low (BTV-1IT2013) virulence strain of BTV. Rams infected with the low virulent BTV strain displayed testicular lesions in the absence of other major clinical signs. Testicular lesions in BTV-infected rams were due to viral replication in the endothelial cells of the peritubular areas of the testes, resulting in stimulation of a type-I IFN response, reduction of testosterone biosynthesis by Leydig cells, and destruction of Sertoli cells and the blood-testis barrier in more severe cases. Hence, BTV induces testicular degeneration and disruption of spermatogenesis by replicating solely in the endothelial cells of the peritubular areas unlike other gonadotropic viruses. This study shows that a naturally occurring arboviral disease can cause testicular degeneration and affect male fertility at least temporarily

Stress responses in lambs castrated with three different methods

The present work was conducted to evaluate the animal response to stress in lambs caused by three different castration techniques. Forty-six male lambs aged 4-5 months were randomly allocated to one of four groups including Burdizzo (B), scrotal ablation (SA), orchiectomy (OR) and control handling (H). Local anaesthesia (lidocaine 2%) was administered in both spermatic cords and the scrotal neck of lambs before each treatment. Blood samples were collected at -30, -10, +1, +20, +40, +60, +120, and +180 minutes. Serum cortisol concentrations were determined using a competitive immunoassay and the area under the curve (AUC) was calculated for each lamb. The following biochemical parameters were assayed for each animal at each time point: alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and glucose (GLU). The time needed for total lesion resolution and weight gain of each animal was recorded. Orchiectomy elicits the greatest cortisol response, significantly greater than that seen in similarly handled controls (P≤0.01), Burdizzo and scrotal ablation groups (P≤0.05). The serum cortisol AUC was higher in the scrotal ablation group (P≤0.05) than controls, but lower than in the orchiectomy group (P≤0.05). The Burdizzo group didn’t differ from controls. Serum glucose levels of the castrated lambs differed significantly from the control group, following a trend similar to cortisol. No change was seen in ALT, AST, LDH or CK. No difference in weight gain was seen among the groups. Our results suggest that use of the Burdizzo is the preferable castration technique for adult lambs, while scrotal ablation is a valid surgical alternative to orchiectomy and permits more rapid wound healing that is ideal for extensive management where flocks are not under close observation

Transplantation of sheep embrionic stem cells in cartilage lesions: preliminary observations

The aim of this study is to evaluate whether ovine embryonic stem cells transplanted in experimental lesions can differentiate into chondrocyte cells and if the new cartilage is of ialine type

Treatment with embryonic stem-like cells into osteochondral defects in sheep femoral condyles

Background Articular cartilage has poor intrinsic capacity for regeneration because of its avascularity and very slow cellular turnover. Defects deriving from trauma or joint disease tend to be repaired with fibrocartilage rather than hyaline cartilage. Consequent degenerative processes are related to the width and depth of the defect. Since mesenchymal stem cells (MSCs) deriving from patients affected by osteoarthritis have a lower proliferative and chondrogenic activity, the systemic or local delivery of heterologous cells may enhance regeneration or inhibit the progressive loss of joint tissue. Embryonic stem cells (ESCs) are very promising, since they can self-renew for prolonged periods without differentiation and can differentiate into tissues from all the 3 germ layers. To date only a few experiments have used ESCs for the study of the cartilage regeneration in animal models and most of them used laboratory animals. Sheep, due to their anatomical, physiological and immunological similarity to humans, represent a valid model for translational studies. This experiment aimed to evaluate if the local delivery of male sheep embryonic stem-like (ES-like) cells into osteochondral defects in the femoral condyles of adult sheep can enhance the regeneration of articular cartilage. Twenty-two ewes were divided into 5 groups (1, 2, 6, 12 and 24 months after surgery). Newly formed tissue was evaluated by macroscopic, histological, immunohistochemical (collagen type II) and fluorescent in situ hybridization (FISH) assays. Results Regenerated tissue was ultimately evaluated on 17 sheep. Samples engrafted with ES-like cells had significantly better histologic evidence of regeneration with respect to empty defects, used as controls, at all time periods. Conclusions Histological assessments demonstrated that the local delivery of ES-like cells into osteochondral defects in sheep femoral condyles enhances the regeneration of the articular hyaline cartilage, without signs of immune rejection or teratoma for 24 months after engraftment.</br

Embryo transfer and related technologies in sheep reproduction

This paper reviews the status of embryo transfer and the major technologies applied to preimplantation of embryos in sheep. Embryo production from superovulated ewes is hindered by an unpredictable response to hormonal treatment. Progress in this area should be expected by an appropriated control of follicular development with gonadotropin-releasing hormone (GnRH) agonist or antagonist prior to gonadotrophin administration. Simple protocols for the cryopreservation of sheep embryos by vitrification are already available and the development of frozen-thawed blastocysts to term is close to the fresh ones. Further research is required to identify factors able to promote the maturation in vitro of oocytes, namely those obtained from prepubertal animals. Semen and embryo sexing procedures are available in cattle although much less attention was paid to their application to sheep. Among all the reproductive technologies, cloning with embryonic and foetal cells has progressed dramatically in sheep and nuclear transfer has been used to produce transgenic animals as an alternative to pronuclear injection. The production of the first lamb cloned from a somatic cell opened new opportunities in animal breeding as well as exciting lines of basic research. The overall conclusions are that, apart from superovulation, the application of in vitro technologies is likely to evolve rapidly and once applied, a great impact on traditional and new animal productions should be expected. However, a better understanding of the changes in gene expression, induced in embryos by different in vitro manipulation procedures, is necessary to prevent abnormal foetal development. Cette revue traite du transfert d’embryons et des principales biotechnologies appliquées à l’embryon ovin. La production d’embryons, après superovulation, est limitée par la réponse non reproductible au traitement hormonal. Un progrès pourrait venir d’un contrôle approprié du développement folliculaire avec un agoniste ou antagoniste de GnRH appliqué avant le traitement gonadotrope. Des protocoles simples pour la congélation d’embryons ovins par vitrification sont disponibles et, après décongélation, le développement à terme de blastocystes congelés est proche de celui des embryons frais. De nouvelles recherches seront nécessaires pour identifier les facteurs capables de stimuler la maturation in vitro des ovocytes, en particulier ceux d’animaux prépubères. Le sexage des spermatozoïdes et des embryons est possible chez les bovins, mais peu appliqué chez les ovins. De toutes les techniques de reproduction, c’est celle du clonage à partir de cellules embryonnaires ou foetales qui a le plus progressé; le transfert nucléaire a été utilisé pour produire des animaux transgéniques, comme alternative à l’injection dans les pronoyaux. La production du premier agneau cloné à partir d’une cellule somatique a ouvert de nouvelles perspectives en élevage et en recherche fondamentale. En conclusion, excepté dans le domaine de la superovulation, les biotechnologies vont évoluer rapidement; leur application aura certainement un grand impact sur les méthodes traditionnelles et nouvelles de production. Cependant, une meilleure connaissance des effets sur l’expression de gènes embryonnaires induits par les manipulations in vitro serait nécessaire pour éviter un développement foetal anormal

The effect of by-pass linseed oil supplementation on the maternal antioxidant system during the embryo-maternal recognition period in ewes

This study analyzed the effects of dietary supplementation with by-pass linseed oil (LO; rich in α-linolenic acid) on maternal antioxidant systems at Days 14 and 16 of pregnancy in Sarda ewes. This trial used sixteen dry ewes. Eight ewes (CT group) were fed with a control diet without LO, and eight ewes (LO group) were fed with a diet supplemented with LO (10.8 g of α-linolenic acid/ewe/day). Both diets had similar crude protein and energy levels. The experiment included 10 days of an adaptation period and 31 days of a supplementation period. This supplementation period was divided into Period −2 (from Day −15 to −8), Period −1 (from Day −7 to −1; before synchronized mating period/Day 0), Period +1 (from Day +1 to + 7 after mating), and Period +2 (from Day +8 to +15 after mating). Estrous synchronization was induced in all the ewes using an intravaginal sponge (45 mg fluorgestone acetate) for 14 days and equine chorionic gonadotropin (350 UI/ewe) at the end of the treatment. On Days 14 (CT, N = 4; LO, N = 4) and 16 (CT, N = 4; LO, N = 4) after mating, the ewes were slaughtered. Samples of plasma, uterine, and luteal tissues were collected. Thiols, total antioxidant activity (TEAC), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content were measured. On Day 16, thiol and TEAC in luteal tissues were higher in the LO group when compared with the control one (p &lt; 0.05). Moreover, TEAC was higher for the LO group in uterine tissues on Days 14 and 16 (p &lt; 0.05). SOD activity was higher in the LO group in luteal and uterine tissues on Day 14 and Day 16, respectively (p &lt; 0.001). On Day 16, uterine MDA content was lower for the LO group (p &lt; 0.001). No differences were found between groups at the plasmatic level. However, the by-pass LO supplementation enhanced the analyzed antioxidant parameters in luteal and uterine tissues. In conclusion, these results demonstrate that by-pass LO supplementation exerted a positive effect on antioxidative defenses on maternal structures during the embryo-maternal recognition period in ewes. Thus, this could contribute to improving the maternal environment during the embryo-maternal recognition period in mammals

Multiplication of five breeds of "exotic" sheep in New Zealand using the technique of embryo transplantation : a thesis presented in partial fulfilment for the requirements of the degree of Master of Philosophy in animal science at Massey University

Sheep of five* breeds imported into New Zealand and held at a quarantine farm were increased in number through the use of embryo transplantation (ET) procedures. For this, donor ewes after superovulation treatment were inseminated with fresh semen of rams of their own breed and flushed to recover embryos 5 or 6 day after onset of oestrus. The embryos after classification and processing through ten washes of flushing media were transported to a secondary quarantine farm and transferred into synchronised recipient Coopworth and Romney ewes. Some of the surrogate ewes received intravaginal progesterone supplementation (CIDR) for 14 days after transfer. Details of lamb production were recorded. This thesis reports the results of some factors that can affect the success of a commercial ET programme. Among the donor ewes 87-89% of the animals were in oestrus after synchronisation and gonadotrophin treatment. The ewes not in heat often had low or absent superovulatory responses. Superovulation was induced with either FSH-P or Folltropin given as 7 or 8 intramuscular injections at 12 h interval begining 72 h before withdrawal of the progesterone treatment (CIDR). The gonadotrophin dose levels were modified according to the breed and also as the programme progressed. Most of the data were examined within breed. The superovulatory response to either the type of gonadotrophin preparation or the dose levels did not differ significantly. The variation in recovery rate of embryos was not affected by the type of gonadotrophin used, whether the animals treated were flushed on one or two occasions, whether flushing was done 5 or 6 days after oestrus, or according to the ovulatory response (classed as 1-8, 9-16 and >16 corpora lrttea counted). Overall 85% of the ova were fertilised and had developed into embryos. There were no significant differences in fertility between inseminations done in the morning or the afternoon, or when flushed once or twice, or when AI was followed by natural mating, or relative to the ovulatory response. Moreover there was no significant difference within the six breeds in the fertility rate. The quality of the embryos, classified as "good" or "poor" on the basis of their appearance and stage of development consistent with the day of flushing (developmental age), was .significantly affected in several of the breeds by the type of gonadotrophin, the dose levels, the ovulatory response and the age of the embryos when recovered. The pregnancy rate after the transfer of two embryos was 59%, 72%, 60%, 53%, 53%, 46% for recipients carrying DT,FT,FINN,GOT,OXD,WHM embryos, respectively. The comparable ·values for embryo survival were 46%, 57%, 54%, 42%, 40%, 34%, respectively. In general among the factors studied involving breed of recipient, degree of synchronisation between donor and recipient, ovulation rate in the recipient, interval from flushing to transplantation and progesterone supplementation it was found that only the latter factor in the DT, FT and OXD breeds of embryos was significant.The results from this multiplication programme after considering 409 treatments with gonadotrophin gave an average of 6.0 corpora lutea, 3.9 eggs recovered, 3.4 eggs fertilised and 1.5 lambs born per treatment. It is concluded that the low recovery rate and poor survival rate of the embryos are important factors to be overcome if a significant increase in the number of lambs born is to be expected from embryo transplantation. Work to overcome these problems is necessary, but attempts should also be made to increase the OR through modification of the gonadotrophin treatments. Support for this idea is suggested because in some animals with a high OR satisfactory numbers of eggs were fertilised and an increase of good quality embryos was recorded.* Texel (from two sources, Danish (DT) and Finnish (FT) and considered as separate breeds), Finnish Landrace (Finn), Gotland Pelt (Got), Oxford Down (OXD), White Headed Marsh (WHM) breeds