Effects of tumor necrosis factor-alpha on secretion of prostaglandins E2 and F2alpha in bovine endometrium throughout the estrous cycle

To determine the physiological significance of tumor necrosis factor-alpha (TNFalpha) in the regulation of endometrial prostaglandin (PG) release in cattle, we investigated the effects of TNFalpha on the secretion of PGE2 and PGF2alpha by bovine endometrium during the estrous cycle. Bovine uteri were classified into six stages (estrus: Day 0, early luteal 1: Days 2 to 3, early luteal 11: Days 5 to 6, mid-luteal: Days 8 to 12, late luteal: Days 15 to 17 and follicular: Days 19 to 21). After 1 h of pre-incubation, endometrial tissues (20 to 30 mg) were exposed to 0 or 0.6 nM TNFalpha for 4 h. The PGE2 concentrations in the medium were higher in the luteal stages than in the follicular stage and in estrus. In contrast, PGF2alpha concentrations were higher in the follicular stage and in estrus than in the luteal stages. The ratio of the basal concentrations of PGE2 and PGF2alpha (PGE2/PGF2alpha ratio) was higher in the luteal stages than in the follicular stage and in estrus. Although TNFalpha stimulated both PGE2 and PGF2alpha secretion during the entire period of the estrous cycle, the level of stimulation of TNFalpha on PGE2 output by the bovine endometrium does not show the same cyclical changes as that shown on PGF2alpha output. The stimulation of TNFalpha resulted in a decrease in the PGE2/PGF2alpha ratio only in the late luteal stage. Furthermore, TNFalpha stimulated PGE2 secretion in stromal, but not epithelial cells. The overall results suggest that TNFalpha is a potent regulator of endometrial PGE2 secretion as well as PGF2alpha secretion during the entire period of estrous cycle, and that TNFalpha plays different roles in the regulation of secretory function of bovine endometrium at different phases of the estrous cycle.

The improvement of in vitro maturation systems for bovine and porcine oocytes

Recent advances in biotechnology have enabled us to produce cloned and genetically modified cattle and pigs by manipulating in vitro-produced embryos. However, the efficiency is still extremely low, mainly because of the low developmental competence of manipulated embryos. To improve this situation, IVM systems for bovine and porcine oocytes in in vitro embryo production systems must be improved. This paper addresses the selection of ovaries with competent follicles at a slaughterhouse and looking attached sight of oocytes at a lab, and the IVM of oocytes under redox state to enhance the developmental competence of IVM oocytes in cattle and pigs.

In situ localization of infectious bursal disease virus-binding cells by a biotin-streptavidin system

A biotin-streptavidin system was established to directly visualize infectious bursal disease virus (IBDV)-binding cells in cell culture or in fresh tissues. The cells or tissue sections were first incubated with a biotinylated, purified IBDV strain GZ911 and then with a streptavidin-beta-galactosidase conjugate. In the presence of the enzyme substrate X-gal, IBDV-binding cells were labeled in blue color. By applying this method to frozen tissue sections, virus-binding sites were localized in situ in the bursa, spleen, and kidney tissue sections, whereas no positive cells were detected in the thymus tissue sections. Chicken embryo fibroblasts, Vero cells, MOP-8 cells, 293-EBNA cells, PANC-1 cells, and HuTu 80 cells were found to bind to the virus. However, the binding of the virus to MDA-MB-231 cells and SVG p12 cells was undetectable. This method can be employed for the expressional cloning of IBDV receptor and can be applied to studies on other avian viruses.

In vitro hepatobiotransformation of sulphadimethoxine in laying hens

The biotransformation of sulphadimethoxine (SDM) was estimated in liver post-mitochondrial supernatants (S-9) from laying hens. The pathway and activity for hen S-9 were compared with those for cow and pig S-9. The formation of the hydroxylation of SDM, 6-hydroxy SDM (6-OH-SDM), was found only with hen S-9. The N4-acetylating activity of SDM in hen S-9 was lower than in cow and pig S-9. All S-9 from the three species de-acetylated N4-acetyl SDM (N4-AcSDM). With respect to the hydroxylation and N4-acetylation rates in hen S-9, the values incubated at 41 degrees C were higher than those at 37 degrees C (P < 0.01).

Comparison of the effect of two different handling media on rabbit zygote developmental ability

Despite the attention paid to culture media, the relevance of the handling medium at egg recovery/transfer is frequently overlooked. In the present work, we compare the effect of two different handling media (PBS and HEPES-buffered Ham F10, both supplemented with 20% (v/v) FCS), upon in vitro and in vivo developmental ability of in vivo fertilised rabbit zygotes. Zygotes recovered in HEPES-buffered medium (permanence 1 h as maximum) and subsequently cultured in vitro developed more efficiently to the compacted morula (100%) and blastocyst stage (92%) than those recovered in PBS (83% and 76%, respectively, P < 0.05). Zygotes recovered in such media were then further bilaterally transferred to recipient does following a brief in vitro culture period (for 4 hours). At caesarean section (day 28 of pregnancy), significant differences were observed in both the percentage of pregnant uterine horns (PBS: 60% vs. HEPES-buffered Ham F10: 100%) and live birth rates (PBS: 14% vs. HEPES-buffered Ham F10: 34%). Thus when early rabbit zygotes must be handled, even for short incubation periods, the medium is not innocuous.

Quantitative assessment of mast cells and expression of IgE protein and mRNA for IgE and interleukin 4 in the gastrointestinal tract of healthy dogs and dogs with inflammatory bowel disease

OBJECTIVE

To characterize the mucosal IgE network in dogs affected with inflammatory bowel disease (IBD) and compare it with that for healthy dogs.

ANIMALS

9 healthy dogs and 20 dogs with IBD.

PROCEDURE

In situ hybridization of mRNA specific for IgE and interleukin 4 (IL-4) and immunohistochemical analysis for IgE protein and 2 markers of mast cells (ie, tryptase and chymase) were performed on tissue sections obtained from the gastrointestinal (GI) tract and lymph nodes of dogs.

RESULTS

Dogs with IBD had significantly more cells positive for IgE protein and more mast cells in the GI mucosa than healthy dogs. Despite this significant increase in number of cells positive for IgE, cells positive for IgE mRNA were rarely detected in the GI mucosa; most cells positive for IgE mRNA were found in mesenteric lymph nodes. Signal pattern of IL-4 mRNA was similar to that of IgE mRNA.

CONCLUSIONS AND CLINICAL RELEVANCE

The increased numbers of cells positive for IgE and mast cells in dogs with IBD suggest hypersensitivity such as hypersensitivity to bacterial or dietary-derived antigens in the intestinal lumen. Future studies need to elucidate whether this represents a cause of inflammation or is a result of the inflammatory process of IBD.

Partial characterization of retroviruses from boid snakes with inclusion body disease

OBJECTIVE

To characterize retroviruses isolated from boid snakes with inclusion body disease (IBD).

ANIMALS

2 boa constrictors with IBD and 1 boa exposed to an affected snake.

PROCEDURE

Snakes were euthanatized, and tissue specimens and blood samples were submitted for virus isolation. Tissue specimens were cultured with or without commercially available viper heart cells and examined by use of transmission electron microscopy (TEM) for evidence of viral replication. Reverse transcriptase activ ty was determined in sucrose gradient-purified virus. Western blotting was performed, using polyclonal antibodies against 1 of the isolated viruses. Specificity of the rabbit anti-virus antibody was evaluated, using an immunogold-labeling TEM technique.

RESULTS

3 viruses (RV-1, RV-2, and RV-3) were isolated. The isolates were morphologically comparable to members of the Retroviridae family. Reverse transcriptase activity was high in sucrose gradient fractions that were rich in virus. Polyclonal antibody against RV-1 reacted with proteins of similar relative mobility in RV-1 and RV-2. By use of immunogold labeling, this antibody also recognized virions of both RV-1 and RV-2.

CONCLUSIONS AND CLINICAL RELEVANCE

A retrovirus was isolated from boid snakes with IBD or exposed to IBD. Western blot analysis of viral proteins indicated that viruses isolated from the different snakes were similar. Whether this virus represents the causative agent of IBD is yet to be determined. The isolation of retroviruses from boid snakes with IBD is an important step n the process of identifying the causative agent of this disease.

Nitric oxide production by coelomocytes of Asterias forbesi

Vertebrate mononuclear phagocytes produce a plethora of molecules involved in host defense. Among the most potent are the reactive oxygen and nitrogen intermediates. Coelomocytes from invertebrates subserve many of the same functions. In order to determine whether invertebrate phagocytes employ reactive nitrogen intermediates, we investigated the effect of various nonspecific stimulators and invertebrate interleukin (IL)-1alpha- and beta-like molecules on nitric oxide (NO) production. Elevated NO release by stimulated coelomocytes was seen after 24 h. Incubation of stimulated coelomocytes in the presence of arginine analogs inhibited NO release. When invertebrate IL-1-like molecules were added to the coelomocytes, they stimulated the release of NO. Western blot analysis using a polyclonal rabbit antiserum to murine NO synthase detected a band at approximately 125 kDa. These data indicate that coelomocytes are capable of producing and releasing NO and that NO is a chemical mediator that has been conserved as a host defense weapon of phagocytes through evolutionary time.

Parallel faecal and organ Mycobacterium avium subsp. paratuberculosis culture of different productivity types of cattle

Faecal (at least 3 months before slaughtering) and organ examinations were carried out in 611 animals (497 dairy, 69 dual-purpose and 44 beef cattle) originating from eight paratuberculosis infected cattle herds. The diagnosis in cattle was established by routine intestinal culture (ileum and the adjacent lymph nodes) after slaughter. In selected 132 animals, post-mortem intensive culture was performed on tissue samples collected from the gastrointestinal tract (duodenum, jejunum, ileum, ileocecal valve, caecum, rectum) and the corresponding lymph nodes, submandibular, retropharyngeal, tracheobronchial, liver and supramammary lymph nodes, kidney, liver and spleen. In 251 (41.1%) of all 611 animals, Mycobacterium avium subspecies paratuberculosis could be isolated from the faeces; in 164 (65.7%) out of 251 shedding animals the infection was detected in the ileum and adjacent lymph nodes. The detection of M. paratuberculosis by routine intestinal culture of faecal culture positive animals varied from 46.0% in animals shedding 1 CFU (colony forming unit), to 94.7% in massive shedders. On the contrary, M. paratuberculosis was detected by routine intestinal culture in 92 (25.5%) of the 360 faecal culture negative animals. Shedding animals had significantly higher (P<0.01) number of organisms in their organs than non-shedding animals. During the intensive tissue cultivation from selected 132 animals, 72 (54.5%) of them were positive. For the negative animals, no significant difference was found between the detection rate in organs examined after slaughter with routine and intensive method. However, in the subgroup of tissue culture positive animals a highly significant difference (P<0.01) was found by intensive examination (83.0%) compared with the routine examination (60.4%). Out of 72 tissue culture positive animals 73.6% of them harboured M. paratuberculosis in the gastrointestinal tract, 16.7% in the gastrointestinal tract and the parenchymatous organs, tracheobronchial and mandibular lymph nodes. The rest of the 9.7% of the infection was detected in the lymph nodes of head and lungs. Our study concerning the distribution of M. paratuberculosis by intensive examinations revealed a minimum effect of breed and production type on localisation of the agent. Thus, the results suggest that in case of an active infection, M. paratuberculosis can be localised in different organs of animals irrespective of their breed or production type.

Casein secretion and cytological differentiation in mammary tissue from bulls of high or low genetic merit

We evaluated tissue content and secretion of milk proteins by mammary parenchymal explants prepared from tissue of mature Holstein bulls as a possible index for genetic merit. Explants from eight selection-line and eight control-line bulls were cultured for 48 or 96 h in medium with 5% fetal bovine serum with or without the addition of lactogenic hormones. Four selection-line and four control-line bulls were also treated for 7 d with estrogen and progesterone or placebo before tissue was removed on d 15 of the experiment. Overall, tissue content and secretion of casein were increased approximately twofold in selection-line bulls. Differences between genetic lines were evident only with the addition of lactogenic hormones. However, treatment of bulls with steroids was not necessary for casein secretion or detection of differences between genetic lines. Averaged for both lines, 96-h media concentrations of casein were 89-fold greater for explants cultured with added lactogenic hormones. Epithelial cells were classified as nonsecretory, droplet-containing, or degenerated. The appearance of droplet-containing cells was markedly increased in cultures supplemented with lactogenic hormones, and the cells were most often located within epithelial folds or pockets. Only occasionally did we observe areas of alveolar-like tissue. The data demonstrate that it is possible to induce the secretion of casein in mammary explants prepared from sexually mature bulls, that lactogenic hormones markedly stimulate secretion, and that differences in genetic merit may be expressed.

Effect of growth factors and co-culture with ovarian medulla on the activation of primordial follicles in explants of bovine ovarian cortex

It has been proposed that the ovarian medulla exerts an intra-ovarian inhibitory effect on primordial follicle activation in cattle. We tested this hypothesis using cortical ovarian explants and determined whether growth factors could alter follicle activation or primary follicle health. Ovaries were obtained from bovine fetuses, and cortical slices were cultured on Millicell culture inserts for up to 8 days. Within 2 d of culture, the proportion of primordial follicles decreased from 70.1 +/- 3.5 to 6.4 +/- 3.4% (P<0.05), and the proportion of primary follicles increased from 23.8 +/- 3.3 to 79.7 +/- 5.5% (P<0.05). The proportion of secondary follicles was relatively stable (6 to 13%). Morphological examination indicated that 91.9 +/- 3.7, 76.7 +/- 8.8, and 71.8 +/- 10.4% of primordial, primary, and secondary follicles, respectively, were considered to be healthy in slices of fresh tissue; these proportions were not altered by up to 8 d of culture (P>0.05). The proportion of all classes of follicles and their morphological health were not affected by the addition of medullary slices to the culture well, nor by the culture of corticomedullary slices (P>0.05). The addition of FSH, insulin-like growth factor-I, epidermal growth factor, basic fibroblast growth factor, or transforming growth factor-beta did not alter primordial follicle activation or the morphological health of primary or secondary follicles. The addition of transforming growth factor-alpha (TGFalpha) decreased the proportion of primary follicles that were healthy from 67.6 +/- 5.1 to 36.8 +/- 4.7% (P<0.05). In conclusion, these data do not support the existence of a medullary inhibitor of primary follicle activation but suggest a role for TGFalpha in the regulation of primary follicle development.

In vitro development of caprine ovarian preantral follicles

The in vitro growth and developmental pattern of caprine preantral follicles cultured in agar gel was observed. Preantral follicles 50 to 150 microm in diameter were isolated from prepuberal goat ovaries by treatment with collagenase and DNase. The isolated preantral follicles were cultured in agar gel for up to 14 days. A group of 10 follicles in different developmental stages was cultured in a culture well coated with 0.6% agar gel and filled with DMEM medium supplemented with FCS (10%), hypoxanthine (2 mmol/mL), dbcAMP (2 mmol/mL), FSH (100 ng/mL), insulin-transferrin-selenium (ITS) (50 ng/mL), IGF-1 (50 ng/mL), hydrocortisone (40 ng/mL) and antibiotics. Follicle viability was determined under an inverted phase-contrast microscope according to morphological and histological criteria, and follicle growth was assessed by their size and appearance. The results showed that the three-dimensional structures and forms of follicles were basically maintained intact during culture. Primary follicles developed into secondary follicles and a few of them into antral follicles. A large portion of secondary follicles entered the antral stage, and oocytes also acquired growth. The formation of theca lamina and zona pellucida was observed. The survival capacity of secondary follicles was greater than primary follicles. The survival rates for primary and secondary follicles were 11.36% (5/44) and 71.16% (53/74), respectively. During in vitro development the follicles demonstrated dominance. This experiment revealed the preliminary characteristics of the in vitro development of caprine preantral follicles.

Relative deficiency in IgA production by duodenal explants from German shepherd dogs with small intestinal disease

Matched samples of serum, saliva and tears were collected from four groups of dogs; two of the groups were German shepherd dogs (GSDs) either with (Group 1) or without (Group 4) a variety of small intestinal disorders; the remaining two groups were dogs of other breeds, again with (Group 2) or without (Group 3) small intestinal disease. Capture ELISAs were used to measure IgG, IgM, IgA and albumin concentrations within these samples; intestinal humoral immune status of clinical cases was assessed by quantifying immunoglobulin production from duodenal explant cultures.There were no significant differences in IgG, IgM or IgA concentrations in serum, saliva or tears between the different groups of dog. Moreover, no significant differences were noted between groups for IgG, IgM and IgA salivary and tear secretory indices. IgA production by 24-h explant cultures was significantly lower in GSDs compared with non-GSDs with small intestinal disease (groups 1 and 2, respectively), but the numbers of lamina propria IgA(+) plasma cells in duodenal biopsies were not different between groups. These results suggest that there may be a relative deficiency in local IgA secretion in GSDs with small intestinal enteropathies, which is not reflected in either serum IgA concentrations, or in secretion at unaffected mucosal sites. It remains to be determined whether such a deficiency is a breed-related primary defect, or whether it arises secondary to the pathological processes within the intestinal mucosa.

Preparation of an epithelium-free mammary fat pad and subsequent mammogenesis in ewes

The objective of this study was to develop a surgical procedure for the preparation of an epithelium-free mammary fat pad (cleared mammary fat pad; CFP) in ewes. At 7 to 10 d of age, ewe lambs (n = 43, mean BW 9.2 +/- .2 kg at 14 d) were sedated and one mammary gland was locally anesthetized. An incision circumscribing the base of the teat was made and blunt dissection was performed through the extraneous mammary fat pad tissue to enable the parenchyma and teat to be wholly removed. Failure to completely remove the epithelium enabled it to regenerate and grow into the mammary fat pad. Mean diameter of the parenchymal rudiment at 7 to 10 d of age was 8.9 +/- .5 mm (range of 5 to 16 mm). The excision site was closed with wound clips and recovered lambs returned to their dams. The contralateral mammary gland remained intact, allowing it to undergo normal development. Live weight gain was unaffected by this procedure. Ewes were subsequently slaughtered in groups at various stages of prepuberty, puberty, gestation, and lactation. Of 39 operated glands recovered, only one demonstrated epithelial outgrowth within the CFP. Parenchyma within the contralateral, intact gland underwent phases of rapid growth in prepuberty, puberty, and late gestation and was capable of milk synthesis after steroid induction or parturition. Change in weight of the CFP paralleled that of the intact mammary gland to 100 d of pregnancy. Sham CFP surgery was performed on four additional ewes wherein the parenchyma was completely excised and immediately replaced. Sham-operated epithelium populated the mammary fat pad and synthesized milk that could be expressed from the teat. A CFP in sheep will be a useful model for future investigations into the local growth regulatory mechanisms associated with ruminant mammogenesis.

Contact of dog spermatozoa with homologous uterine tube epithelium prolongs flagellar activity in relation to the stage of the estrous cycle

There is scant information about the storage of spermatozoa within the reproductive tract of the bitch. In several species the uterine tube plays a significant role in sperm storage. The present study was performed to investigate the interaction between spermatozoa and the epithelium of the uterine tube, in particular how this interaction might influence the flagellar activity of spermatozoa in relation to the stage of the estrous cycle. Epithelium was harvested from uterine tubes of 24 bitches at various stages of the estrous cycle (estrus, luteal phase or anestrus), and cultured with pooled spermatozoa collected from 6 dogs. Spermatozoa rapidly bound to the epithelial surface by their heads and the majority of attached spermatozoa were motile. The intimate association between spermatozoa and the uterine tube epithelium maintained motility in a manner that was related to the stage of the estrous cycle. Flagellar activity was significantly greater for spermatozoa bound to estrous epithelium than epithelium from the luteal phase or anestrus. On average, approximately 10% of spermatozoa that were attached to the uterine tube epithelium of estrous bitches retained their flagellar activity for 48 h after innoculation. There was no apparent influence of the region of the uterine tube on this effect. These findings suggest that the uterine tube may form a functional spermatozoal reservoir in the bitch.

Tissue culture of the enteric nervous system from equine ileum

Ileal samples were harvested fresh from euthanized adult horses. The tissues were microdissected to prepare wholemount preparations for immunohistochemistry and for either explant or dissociated culture systems of the enteric nervous system. Explant culture systems were established using whole-mounts of either the submucous plexus or the muscularis externa (including the myenteric plexus). Dissociated cell cultures could only be obtained from the submucous plexus. Culture systems were maintained for up to 5 days. Immunoreactivity for a neuronal marker (Pan-N) and for glial cell markers (GFAP and S100) indicated the presence of both neurons and enteric glia in the tissue culture preparations. This is the first report of equine enteric neurons being grown in tissue culture Further refinements to the techniques will be required before this in vitro model can be used for quantitative analysis.

The protective action of polyvinyl alcohol during rapid-freezing of mouse embryos

Biological products like serum and BSA are routinely used in embryo freezing solutions. These products are undefined and can potentially expose the embryos to infectious agents. Therefore, this experiment was designed to evaluate in vitro and in vivo survival of mouse embryos frozen in solutions supplemented with a chemically defined macromolecule, polyvinyl alcohol (PVA). Morula-stage embryos from superovulated mice were collected, frozen by a rapid freezing procedure, and cryoprotectant diluted out (after thawing) in media supplemented with either 10% fetal calf serum (FCS), 0.1 mg/mL PVA, or a combination of 10% FCS and 0.1 mg/mL PVA. Frozen-thawed (good to excellent quality) and nonfrozen (control, collected in FCS supplemented medium) embryos were cultured in medium M16 (32) supplemented with either 4 mg/mL BSA or 0.1 mg/mL PVA for 72 h. Embryos frozen in solutions supplemented with FCS or PVA and nonfrozen embryos were transferred to pseudopregnant recipients. Recipients were humanly killed on Day 15 after transfer, and the rate of implantation and percentage of live fetuses were recorded. The supplementation of collection, freezing and cryoprotectant dilution solutions with FCS, PVA or FCS plus PVA did not influence (P > 0.05) the rate of survival and in vitro development of embryos to hatched/hatching blastocyst-stage. However, a higher (P < 0.01) in vitro development rate to hatching/hatched-stage was recorded when frozen-thawed embryos were cultured in medium supplemented with BSA than with PVA. There was no difference (P > 0.05) in the rate of implantation (68 vs 72%) or percentage of live fetuses (62 vs 60%) between pregnant recipients with embryos frozen in medium with FCS or PVA. The rate of implantation and development of embryos frozen in medium supplemented with PVA or FCS was comparable (P > 0.05) to that of nonfrozen embryos. It may be concluded that PVA can be substituted for FCS in medium for freezing mouse embryos; however, it can not be completely substituted for BSA in the in vitro culture of embryos to the hatched blastocyst stage.

Exogeneous substances affecting development of in vitro-derived bovine embryos before and after embryonic genome activation

Three experiments were conducted to evaluate how exogenous substances [fetal bovine serum (FBS), arachidonic acid (AA), glutathione (GSH), platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF), fibroblast growth factor (FGF), insulin, transferrin and selenium (ITS)] affect preimplantation bovine embryo development. Cumulus-oocyte complexes (COC) were matured and fertilized in vitro, and their development was monitored up to 192 h post insemination in a two-step culture system. In Experiment 1, inseminated oocytes were cultured in modified bovine embryo culture medium (mBECM) supplemented with FBS or BSA for up to 60 h post insemination, and the resultant 8-cell embryos were then cultured singly in mBECM supplemented with AA+GSH+PDGF+TGF. More (P<0.005) blastocysts were derived from 8-cell embryos produced in media containing FBS than BSA. In Experiment 2, the 8-cell embryos produced in mBECM supplemented with FBS were cultured singly in mBECM as follows: 1) no supplementation; 2) AA and GSH or 3) AA, GSH, PDGF and TGF. Compared with no supplementation, a significant (P<0.05) increase in the proportion of 16-cell embryos and morulae was obtained after the addition of either AA+GSH or AA+GSH+PDGF+TGF. In Experiment 3, oocytes were cultured singly in mBECM as follows: 1) no supplementation; 2) AA+GSH+PDGF+TGF; 3) AA+GSH+PDGF+TGF and FGF; 4) AA+GSH+PDGF+TGF and ITS; 5) AA+GSH+PDGF+TGF, FGF and ITS or 6) FBS. Eight-cell embryos grown in each system were subsequently cultured singly in mBECM with AA+GSH+PDGF+TGF. More (P<0.05) 16-cell embryos were obtained in medium supplemented with either AA+GSH+PDGF+TGF and ITS or FBS than in unsupplemented medium. Fewer (P<0.05) oocytes developed to the 8-cell stage with the addition of AA+GSH+PDGF+TGF and FGF than without. In conclusion, embryo development to the blastocyst stage is regulated by exogenous AA, GSH, PDGF, FGF and ITS in a stage-specific manner.

A tissue culture system to study respiratory ciliary epithelial adherence of selected swine mycoplasmas

An in vitro culture system for swine tracheal epithelial cells was developed to study the adherence of swine mycoplasmas. Swine tracheal epithelial cells were isolated by enzymatic digestion and cultured on microporous membranes. Growth medium was placed under the membrane support to create air-liquid interface feeding resulting in the cells growing cilia and microvilli on the apical surface. Two strains of Mycoplasma hyopneumoniae (pathogenic strain 91-3 and non-pathogenic type strain J) and two strains of Mycoplasma flocculare (type strain Ms42 and field isolate 7160T) were used in this study. The morphology of the cultured tracheal cells was evaluated by transmission electron microscopy. Adherence of M. hyopneumoniae and M. flocculare and damage to the cilia were demonstrated using scanning electron microscopy. The pathogenic M. hyopneumoniae strain 91-3 adhered to cilia inducing obvious damage. The non-pathogenic M. hyopneumoniae strain J did not adhere to mature cilia. Both M. flocculare strains Ms42 and 7160T adhered to mature and budding cilia. No obvious ciliary damage was observed with strain Ms42. Minimal damage consisting of a slight tangling of the cilia occurred after adherence by strain 7160T. This model will enable us to further study the role of adherence of mycoplasmas on the pathogenesis of swine pneumonia.

Effects of catecholamines in vitro on lipogenesis in cultured adipose tissue from young goats

Freshly prepared and cultured perirenal and omental adipose tissue explants were used to investigate the effect of age and hormones on lipogenesis in young goats. Perinatal (1-2 days of age) and older (24-32 days of age) male goats were used. Adipose explants were cultured (24 h) in the presence of insulin, cortisol and recombinant bovine growth hormone (bST) and subsequently incubated (2 h) in a glucose-free buffer containing (14C)-acetate in the presence or absence of noradrenaline (Ne) and isoprenaline (Iso) to measure tissue lipogenic responses to hormones added to the culture medium and to measure the responsiveness to catecholamines. Inclusion of hormones in the culture medium did not change lipogenesis during subsequent acute incubation in glucose-free buffer in both perirenal and omental adipose tissue from perinatal goats. On the other hand, in perirenal explants from older animals, insulin alone or insulin plus cortisol increased (P < 0.05) and cortisol alone decreased (P < 0.05) the rate of fatty acid synthesis. When perirenal explants were cultured in the presence of insulin plus cortisol plus bST, the rates of lipogeneses were lower (P < 0.05) than those in cultures with insulin plus cortisol. A similar pattern of the effects of hormones on the rates of fatty acid synthesis was also seen in omental explants; however, these effects were not significant. In vitro rates of lipogeneses were decreased (P < 0.05) by Ne but not Iso in freshly prepared omental explants of both perinatal and older animals and in freshly prepared perirenal explants of older animals. In cultured perirenal explants of both perinatal and older animals the mean values of lipogenesis were decreased (P < 0.05) by both Ne and Iso. However, in cultured omental explants both catecholamines were effective (P < 0.05) in older but not in perinatal animals.

Secretion of interferon-tau by bovine embryos in long-term culture: comparison of in vivo derived, in vitro produced, nuclear transfer and demi-embryos

Interferon-tau (IFNtau) is the pregnancy recognition signal of bovine embryos, inhibiting luteolysis. We studied trophoblastic growth and IFNtau secretion of embryos with different developmental potential, i.e., in vivo derived and in vitro produced embryos, cloned embryos and demi-embryos, to evaluate if the ability of secreting IFNtau might be responsible for differences in pregnancy rates after transfer of these categories of embryos to recipients. Day 8 embryos of excellent quality were individually placed in microdrops of buffalo rat liver cell-conditioned medium and maintained for up to 23 days. Embryos were observed on Days 11, 15, 19 and 23, the mean diameter (2r) of attached and spherical embryos was measured, and their trophoblastic area was calculated as r2pi or 4r2pi, respectively. Simultaneously, medium was changed and the IFNtau levels of conditioned media were determined using a bioassay of antiviral activity. Trophoblastic area was smaller (P < 0.05) in demi-embryos than in all other groups, which exhibited similar trophoblastic growth until Day 19. However, on Day 23 trophoblastic area of in vivo derived embryos was more than twice (P < 0.05) as large as those of in vitro produced and nuclear transfer (NT) embryos. IFNtau levels increased only slowly with time in culture of demi-embryos. By contrast, the level of IFNtau doubled from Day 11 to Day 15 in conditioned media from all other groups of embryos. The linear increase in IFNtau production of vivo and in vitro derived embryos continued until the end of the culture period, whereas conditioned media from NT embryos contained significantly (P < 0.05) less IFNtau activity on Days 19 and 23 than those of the former two groups. Our results demonstrate different capabilities of secreting IFNtau for in vivo derived and in vitro produced embryos vs. NT and demi-embryos, which may--at least part--be responsible for the differences in pregnancy rates after transfer to recipients.

Maturation, fertilization and complete development of porcine oocytes matured under different systems

This study was designed 1) to determine the effectiveness of 2 in vitro maturation systems commonly employed to produce nuclear and cytoplasmically mature pig oocytes, 2) to assess the effects of boar, sperm concentration and maturation system on oocyte penetrability and male pronucleus formation and 3) to determine the ability of the in vitro matured oocytes to be fertilized in vivo by artificial insemination (AI) of sows. The differences examined between the 2 maturation systems included the culture medium (Waymouth vs TCM199), hormones, additives, culture conditions (static vs gentle agitation) presence or absence of porcine follicular fluid (PFF) and presence or absence of follicular shells. The results showed that nuclear maturation rate was similar in both systems (83.3 +/- 3.5 vs 86.4 +/- 2.5%), and intracellular content of glutathione was 5.21 +/- 0.73 vs 3.5 +/- 0.39 pmol/oocyte, although no correlation between these parameters was observed. The penetration rate and number of sperm cells per oocyte were dependent on the boar, maturation system and sperm concentration, but the rate of male pronuclear formation seemed to be influenced only by the boar and the maturation system but not by sperm concentration. In vivo fertilization of in vitro matured oocytes showed that both maturation systems could yield viable oocytes since 3 of 4 gilts and 2 of 4 gilts, respectively, became pregnant. Failure to become pregnant was not associated with inadequate oocyte maturation since control gilts, which received their own ovulated oocytes rather than in vitro matured oocytes at transfer, also did not become pregnant. We conclude that polyspermy may be an inherent problem in the IVF but not in the IVM systems.

In vitro development of individually matured bovine oocytes in relation to follicular wall atresia

Morphologically good-quality cumulus oocyte complexes (COCs) can originate from slightly atretic follicles. Biochemical and ultrastructural investigations reveal that a very high percentage of bovine antral follicles express some degree of atresia. The aim of the present study was to determine the developmental competence of good quality COCs in relation to their biochemically estimated follicular wall apoptosis. For experimental design a single oocyte maturation system was established, followed by group culture processing oocytes together according to their level of follicular wall atresia estimated by an ELISA for apoptotic cell death. Single oocyte culture during maturation reduced the developmental capacity of oocytes significantly (P < 0.01), with 5% blastocysts versus 25% after common group culture. Blastocyst formation for single oocyte maturation was found exclusively in oocytes isolated from luteal stage ovaries with low degree of apoptosis. The level of follicular wall apoptosis in luteal stage follicles (0.79 +/- 0.05 units/mg protein, n = 198) was lower than in follicular stage follicles (1.14 +/- 0.05 units/mg protein, n = 208). This was caused by significant higher levels in small (< 3.5 mm diameter) and large (> 5.5 mm diameter) follicles of the latter group. In conclusion, despite reduced developmental capacity after single oocyte maturation, we were able to reveal some functional relationship between oocyte origin and quality. It was shown that morphologically good quality COCs isolated from follicles with higher degree of apoptosis lose their developmental capacity.

Studies on a chemically defined medium for in vitro culture of in vitro matured and fertilized porcine oocytes

The present study evaluated the effects of various components in a chemically defined medium on the development of IVM/IVF porcine embryos. The investigated components included energy substrates (lactate, pyruvate or glucose, alone or in various combinations), amino acids (glutamine, glycine or alanine), PVP and HEPES buffer. The effects of each energy substrate were the same as the control. However, a mixture of lactate with either of the other energy substrates increased the development rate. Glutamine tended to decrease rate of the development more than other amino acids, and this inhibition was dose dependent. Both PVP and HEPES buffer did not affect development rate. However, more than 35 mM HEPES buffer induced fragmentation From the above results, a new culture medium was designed (supplemented with 0.276 mM glycine, 0.176 mM alanine, 15 mM HEPES buffer and 1% (wt/vol) PVP in BSA-free Whitten's medium with or without glucose). The new medium resulted in a higher embryo development rate (20.4 and 16.3%) than that obtained with the control medium (10.0%).

Effect of hyaluronic acid on the development of porcine 1-cell embryos produced by a conventional or new in vitro maturation/fertilization system

In pigs, it is difficult to produce normal fertilized embryos from immature oocytes in vitro. However, a new maturation/fertilization system in which the percentage of normal fertilized embryos is comparatively high has been developed recently. In the present study, porcine 1-cell embryos were produced both by a conventional and a new system and then cultured in NCSU-23 supplemented with hyaluronic acid at various concentrations. In the conventional system, the percentage of oocytes with monospermic penetration and 1 male pronucleus and 1 female pronucleus was only 6%. At 144 h after insemination, the percentage (5%) of embryos developing to the blastocyst stage in medium supplemented with 0.5 mg/mL hyaluronic acid was significantly (P<0.05) higher than that (2%) in medium without hyaluronic acid. When oocytes were matured and inseminated using the new system, monospermic penetration and the formation of 1 male and 1 female pronucleus were observed in 69% of the penetrated oocytes. However, blastocyst formation (8 to 14%) at 144 h after insemination was not affected by the concentration (0 to 1.0 mg/mL) of hyaluronic acid. These results indicate that the effect of hyaluronic acid on the development of in vitro-produced porcine embryos varies with the conditions of oocyte maturation and fertilization.

Allopurinol, an inhibitor of xanthine oxidase, improves the development of IVM/IVF bovine embryos (>4 cell) in vitro under certain culture conditions

To determine the origin of free oxygen radicals in the culture medium of bovine embryos, the effect of allopurinol, an inhibitor of xanthine oxidase, on the development of embryos (>4 cell) in modified synthetic oviduct fluid (m-SOF) medium was examined. When embryos were cultured in the presence of 0.2 mM allopurinol under high oxygen tension (5% CO2 in air), the blastocyst rate significantly (P<0.05) increased compared with the absence of allopurinol (allopurinol (+) 42 vs. (-) 25%; Day 6, 63 vs. 51%; Day 7, 69 vs. 58%; Day 8). However, allopurinol had no effect on embryo development under low oxygen tension (5% CO2, 5% O2, 90% N2). Moreover, it was found that the developmental rate and the total cell number of blastocysts decreased (development rate: 60 vs. 28%, cell number: 132 vs. 74) when the embryos were cultured in medium containing 0.01 U/mL xanthine oxidase (XOD) and 0.1 mM hypoxanthine (HXT), and the damaging effect of XOD and HXT was removed by the addition of 0.2 mM allopurinol. The beneficial effect of allopurinol was also observed when the glucose concentration was increased to 4.5 mM from 1.5 mM (control: 22% vs. allopurinol: 34%; Day 8), but no beneficial effects were observed in the media without glucose (control: 55% vs. allopurinol: 59%). Taken together, these results suggested that a portion of the free oxygen radicals are generated from the XOD and HXT reactions under culture conditions, and this generation is enhanced by high oxygen tension in the gas atmosphere or by high glucose concentrations in the medium.

Tissue culture-propagated orf virus vaccine protects lambs from orf virus challenge

Twenty, eight-day-old specific pathogen-free (SPF) lambs were vaccinated by a single scarification approximately 4 cm in length on the inner right thigh with a double-pronged applicator. The titre of live virus in the vaccine was 10(7.2) TCID50/ml and the estimated dose per lamb was 0.04 ml. Three months and six months later 10 of the vaccinated lambs and five age-matched unvaccinated control specific pathogen free lambs were challenged by a single scarification with virulent virus on the inner left thigh in the same way. After the vaccination all 20 lambs developed lesions characteristic of orf virus infection that had largely resolved four weeks later, when they all had reciprocal ELISA antibody titres > or = 3200 that persisted in all but one of them until they were challenged. After the challenge, the development of lesions in the vaccinated and unvaccinated sheep was compared daily for four weeks by means of a clinical scoring system. Both groups of vaccinated lambs had significantly lower (P < 0.01) total clinical scores after challenge at three months and six months than the unvaccinated lambs.

An in vitro culture method for chick embryos obtained from the anterior portion of the magnum of oviduct

1. Chick embryos, obtained from the anterior portion of the magnum of the oviduct 60 to 80 min after the preceding egg had been laid, were cultured in vitro in small and large recipient eggshells until hatching. 2. Of 82 embryos cultured, 46.3% had survived to day 4 of incubation, and 19.5% survived to hatching. 3. The method for culturing embryos used in this experiment could facilitate research on the in vitro manipulation of early chick embryos.

Collection, in vitro fertilisation and culture of bovine oocytes intravaginally or in a conventional incubator

The aim of this study was to test the feasibility of intravaginal culture for in vitro fertilisation and production of bovine embryos. Oocytes were collected from five cows, superovulated with ovine follicle stimulatory hormone (oFSH), by using a 7.5 MHz rectal linear array ultrasound transducer. From 124 follicles punctured, the oocyte recovery rate was 48 per cent. Fifty-one oocytes were placed in capsules either in the vagina or in an incubator, and cocultured with sperm for 24 hours followed by coculture with oviductal cells for 48 hours. There was no significant difference between the fertilisation rates or the cleavage rates achieved by the two systems and the mean fertilisation rate was 44 per cent. However, the fertilised oocytes did not develop beyond the eight-cell stage.

Embryonic stem cells in farm animals

Embryonic stem cell technology is now well established in the mouse (reviewed by Robertson, 1987). This technology implies the isolation from the preimplantation embrao of a cell line (ES) that is cultured in vitro in an undifferentiated state. Embryonal carcinoma cells (EC) lines obtained from malignant tumours (Martin, 1975), together with all the information available on their culture requirements (reviewed by Heath, 1987), represented a very important starting point for the establishment of ES cells (Martin, 1981). ES cells share many characteristics with EC cells such as the ability to contribute to somatic tissues of animals obtained following injection of cells into a host blastocyst, to differentiate in vitro under appropriate stimuli (Rudnicki & McBurney, 1987) and to form retransplantable tumours. ES cells, however, have substantial advantages over EC cells in that they can be derived directly from a normal embryo, they maintain a normal karyotype and when reintroduced into a host blastocyst they can colonise the germ line (Bradley, 1987). ES cells are maintained in an undifferentiated state by the presence of feeder layers producing various factor(s) that prevent to the cells from differentiating. It has been shown that glycoproteins are responsible for this effect and these have been named according to their different activities: DIA, differentiation inhibitory activity (Smith & Hooper, 1987); LIF, leukaemia inhibiting factor (Smith et al, 1988; Williams et al, 1988); HILDA, human interleukin for DA cells (Moreau et al., 1988). It is now possible to establish and maintain ES cells in culture in the absence of feeders cells but in the presence of such factors (Nichols et al., 1990).

Steroid synthesis by equine conceptuses between days 7 and 14 and endometrial steroid metabolism

The objective of this study was to determine if changes in steroid synthesis occurred in the horse blastocyst about the time of maternal recognition of pregnancy. Embryos collected between days 7.5 and 14.5 were incubated for 8 hr in vitro in HAM's F10 containing radiolabelled pregnenolone. The steroid metabolites in the incubation medium were separated by reverse phase HPLC and the major peaks expressed as a percentage of total metabolites. It was found that there were no major changes in the profile of metabolites throughout the period of study, although there was increased conversion as the conceptuses developed. It was found that the major metabolite produced was 17 alpha-hydroxyprogesterone and not estradiol as expected. A second experiment was conducted to determine if 17 alpha-hydroxyprogesterone was metabolized by endometrial tissue. Endometrial biopsies from anestrous mares and from pregnant and nonpregnant mares at day 11 were incubated with radiolabelled 17 alpha-hydroxyprogesterone, progesterone or pregnenolone. The 17 alpha-hydroxyprogesterone, but not progesterone nor pregnenolone, was converted to a more polar metabolite in all groups. Production of this metabolite was significant greater in the anestrous mares. This metabolite has not been unidentified conclusively. Thus, results of this study show that 17 alpha-hydroxyprogesterone is the major steroid synthesized by the equine blastocyst and that this steroid is further metabolized to an unidentified steroid by the endometrium. These steroids could play a role in conceptus development or maternal recognition of pregnancy.

Pathogenesis of equine herpesvirus-1 in specific pathogen-free foals: primary and secondary infections and reactivation

Six specific pathogen-free foals shown to be free of equine herpesvirus-1 and 4 (EHV-1 and -4) and lacking in maternally-derived antibodies were used to investigate the pathogenesis of EHV-1 in horses. Following primary intranasal inoculation with EHV-1 all foals showed signs of a mild, self-limiting upper respiratory tract infection. A leucopenia was observed, comprising both a lymphopenia and neutropenia. Virus was isolated from nasal mucus and buffy coat cells over several days during the clinical episode and after the animals became clinically normal. Notwithstanding the mildness of the clinical disease, virus was not eliminated completely and intravenous administration of dexamethasone resulted in reactivation of latent EHV-1 in animals which had received only a single dose of the virus. In a second infection given to four foals, 61 days after the primary inoculation, no clinical signs were observed, haematological changes were minimal and viraemia was absent.

Na-transport during long-term incubation of the hen lower intestine: No aldosterone effect

1. In order to test the aldosterone effect in vitro, Na-transport of the coprodeal epithelium from hens on low-NaCl diet was measured in the Ussing chamber for up to 8 hr. Short-circuit current (SCC, near equal to the amiloride inhibitable Na-transport) was recorded. 2. Incubation media were either Krebs-phosphate or bicarbonate buffer with and without addition of beta-hydroxybutyrate, glutamine and mannose as "metabolic fuels". The media were replaced every hour. The Krebs-phosphate buffer was further tested with and without indomethacin and media replacement. Na-transport was best maintained in this buffer with replacement: SCC at 4 hr: 156 +/- 21 microA/cm2, 8 hr: 73 +/- 14 microA/cm2. 3. The aldosterone experiments were carried out on tissues from hens resalinated for 24 hr. No effects were demonstrated at concentrations up to 10(-5) M. The SCC showed an unexpected raise within 2-4 hr to a very high level (4 hr: 221 +/- 61 microA/cm2) both in the control and in all aldosterone-treated tissues. This SCC decreased slowly to 210 +/- 29 microA/cm2 at 8 hr. It was abolished by amiloride. 4. No increase in SCC was observed in tissues from hens after 48 and 72 hr of resalination either after aldosterone or on chronic high-NaCl diet.

Development of cultured quail embryos

Japanese quail embryos were cultured by a plastic wrap technique after 2.5 days of normal incubation, and their development was investigated. Mean survival time was 13 days (2.5 days of preincubation plus 10.5 days of experimental culture). Mean morphological stage shown by the cultured embryos was Stage 28 of Zacchei (1961) (corresponding to 11 days of normal incubation) and the maximum stage of development was Stage 31 (corresponding to 14 days of normal incubation). In the latter half of incubation periods, cultured embryos showed retarded development, and their size was smaller than intact control embryos. Because continual observation of embryos is possible, this culture technique would be useful for experimental manipulation of the embryos or studies on lethal genes.