Randomised trial of the bioavailability and efficacy of orally administered flunixin, carprofen and ketoprofen in a pain model in sheep

OBJECTIVE

To determine the efficacy and bioavailability of non-steroidal anti-inflammatory drugs (NSAIDs) when administered orally to sheep.

DESIGN

Randomised experimental design with four treatment groups: three NSAID groups and one control group (n = 10/group). The study animals were 40 18-month-old Merino ewes with an average weight of 31.4 ± 0.5 kg.

METHODS

Treatment was given orally at 24 h intervals for 6 days at dose rates expected to achieve therapeutic levels in sheep: carprofen (8.0 mg/kg), ketoprofen (8.0 mg/kg) and flunixin (4.0 mg/kg). Oil of turpentine (0.1 mL) was injected into a forelimb of each sheep to induce inflammation and pain; responses (force plate pressure, skin temperature, limb circumference, haematology and plasma cortisol) were measured at 0, 3, 6, 9, 12, 24, 36, 48, 72 and 96 h post-injection. NSAID concentrations were determined by ultra-high-pressure liquid chromatography.

RESULTS

The NSAIDs were detectable in ovine plasma 2 h after oral administration, with average concentrations of 4.5-8.4 µg/mL for ketoprofen, 2.6-4.1 µg/mL for flunixin and 30-80 µg/mL for carprofen. NSAID concentrations dropped 24 h after administration. Pain response to an oil of turpentine injection was assessed using the measures applied but no effect of the NSAIDs was observed. Although this pain model has been previously validated, the responses observed in this study differed from those in the previous study.

CONCLUSIONS AND CLINICAL RELEVANCE

The three NSAIDs reached inferred therapeutic concentrations in blood at 2 h after oral administration. The oil of turpentine lameness model may need further validation.

187 INCREASED EFFICIENCY OF DERIVING BOVINE STEM CELL-LIKE COLONIES USING VALPROIC ACID AND SMALL-MOLECULE COCKTAILS

Nonviral reprogramming of bovine embryonic and adult fibroblasts was undertaken using electroporation of a polycistronic plasmid carrying human reprogramming factors Oct4, Sox2, Lin28, and Nanog (Addgene Plasmid #20922). Because of difficulties encountered in reliably and reproducibly reprogramming bovine cells to a pluripotent state, several small-molecule combinations have been tested to support reprogramming. Previously, a combination of three molecules, (sodium butyrate, PD0325901 and SB431542; NaB-PD-SB) in induced pluripotent stem (iPS) medium [Minimum Essential Medium Alpha, 20% FBS, 1x insulin-transferrin-selenium (ITS), 2 mM Glutamax (Gibco, Grand Island, NY, USA), 100 μM nonessential amino acids (NEAA), 50 U mol–1 penicillin, 50 mg mL–1 streptomycin, 0.1 mM β-mercaptoethanol, 4 ng mL–1 human leukaemia inhibitory factor, and 10 ng mL–1 basic fibroblast growth factor] was found to accelerate the reprogramming process of bovine iPS cells, with colonies observed at 12 days post-electroporation, as opposed to 21 days without the addition of the small-molecule cocktail. The addition of 1 mM valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, in combination with the other small-molecule cocktail (NaB-PD-SB), was found to improve the reprogramming efficiency of bovine adult and embryonic fibroblasts, with colonies observed at Day 10 post-electroporation, and the average number of colonies present per 10-cm dish, rising from an average of 5 colonies observed in the NaB-PD-SB cocktail to 27 with the addition of VPA. Colonies grown in the presence of VPA had a consistent morphology, forming compact domed colonies consisting of small round cells with well-defined borders. It was observed that colonies growing in the presence of VPA tended to have a better defined border and grew larger in size than those grown in the presence of NaB-PD-SB alone. Colonies began to differentiate after 21 days and were no longer alkaline phosphatase positive after this time. Cells were either harvested for mRNA extraction or differentiated into embryoid bodies (EB). Expression of pluripotency genes, Oct4, Sox2, Klf4, Nanog, and Alkaline Phosphatase were significantly increased in the presence of VPA compared to nonreprogrammed somatic bovine fibroblasts, with expression profiles similar to those grown in the NaB-PD-SB cocktail. Embryoid bodies were analysed for gene expression of different germ layer markers, FOXA2 (endoderm), Nestin and TUBB3 (ectoderm), and Desmin (mesoderm) using quantitative RT–PCR. For both EBs derived from the NaB-PD-SB cocktail and those with VPA, at least one marker from each germ layer was present, demonstrating the potential potency of these cells. At least a 10-fold increase in expression of these was observed in comparison to somatic fibroblast cells. It is apparent that the addition of small molecules can assist in the reprogramming of bovine iPS cells, and addition of VPA to the cocktail results in more consistent putative bovine iPS colonies. Further work is needed to identify the causes for early differentiation of colonies in order to obtain fully reprogrammed pluripotent stem cells.

281 USE OF SMALL MOLECULES ENHANCES REPROGRAMMING SUCCESS IN BOVINE DERMAL FIBROBLASTS

Reprogramming of differentiated cells to induced pluripotency holds tremendous potential for livestock reproduction. Here we report use of small molecules to support the generation of stem cell-like colonies from bovine dermal fibroblasts that show characteristics of pluripotent cells. Reprogramming of bovine somatic cells was undertaken by introducing canonical reprogramming factors Oct4, Sox2, Klf4, and c-Myc through a lentiviral drug-inducible polycistronic vector. Several small molecules were tested to support reprogramming. A combination of 3 small molecules (sodium butyrate, PD0325901, and SB431542; NaB-PD-SB) in iPS medium [Minimum Essential Medium Alpha, 20% fetal bovine serum, 1× insulin-transferrin-selenium (ITS), 2 mM Glutamax, 100 µM NEAA, 50 U mol–1 penicillin, 50 mg mL–1 streptomycin, 0.1 mM β-mercaptoethanol, 4 ng mL–1 human leukemia inhibitory factor, and 10 ng mL–1 basic fibroblast growth factor] was found to accelerate the kinetics of the reprogramming process. Colonies appeared at 12 days of culture compared with 21 days in iPS medium alone (P < 0.01, n = 5). Colonies in NaB-PD-SB iPS medium had consistent morphology, with small cells in compact dome formations with well-defined colony borders. Cells were not passaged but were either harvested for mRNA extraction or differentiated into embryoid bodies. Gene expression of the reprogramming factors in stem cell-like colonies was confirmed by qRT-PCR, and further gene expression analysis revealed activation of Nanog and ALPL mRNA expression (P < 0.01, n = 2). Embryoid bodies were analysed for gene expression by quantitative RT-PCR. Silencing of the transgene was not observed in embryoid bodies despite withdrawal of the inducer doxycycline. Expression of the endoderm marker FOXA2, ectoderm markers NES and TUBB3, and mesoderm marker DES was strongly increased in embryoid bodies compared with non-reprogrammed bovine fibroblasts (P < 0.01, n = 2), confirming expression of marker genes for the 3 germ layers.

Effects of evaporative cooling on reproductive performance and milk production of dairy cows in hot wet conditions

Fourteen animals of second and third lactation of Thai Friesian crossbred cows (87.5% Friesian x 12.5% Bos indicus) located at Sakol Nakhon Research and Breeding Centre, Department of Livestock Development, Ministry of Agriculture and Cooperatives, were divided randomly into two groups of seven each to evaluate the effects of evaporative cooling on reproductive and physiological traits under hot, humid conditions. Results indicated that installation of evaporating cooling in the open shed gave a further improvement in ameliorating heat stress in dairy cows in hot-wet environments by utilising the low humidity conditions that naturally occur during the day. The cows housed in an evaporatively cooled environment had both a rectal temperature and respiration rate (39.09 degrees C, 61.39 breaths/min, respectively) significantly lower than that of the non-cooled cows (41.21 degrees C; 86.87 breaths/min). The former group also had higher milk yield and more efficient reproductive performance (pregnancy rate and reduced days open) than the latter group. It is suggested that the non-evaporatively cooled cows did not gain benefit from the naturally lower heat stress during night time.

263. The successful use of busulfan to deplete endogenous spermatogonia in ram testes

Our research into germ cell transfer builds upon murine research1 and is aimed at using this technique in livestock species. To increase the efficiency of colonization of transplanted germ cells, the recipient testes must be depleted of endogenous spermatogonia, without affecting the supporting cells. Three depletion methods were investigated, heat, cold and chemotherapy. Our first investigation looked at the direct cooling (0ºC) and heating (45ºC) of the testes of 4–6 week old ram lambs. Testes were collected 7 days post treatment. The second investigation involved the systemic injection of busulfan to ram lambs aged 3-4 months. Busulfan is used for preparing recipient mice for testes cell transfer.1 At doses affecting the stem cells of the testes, busulfan will result in mylosuppression. Therefore a preliminary dose response trial was conducted at dose rates 4, 8 and 16mg/kg to determine the most effective dose, without threatening the survival of the animal. Testes were recovered after 3 and 6 weeks. All testes sections followed routine histology and immunochemistry with PGP 9.5 (Table 1). For the heat and cold study, only gonocytes were present and there were no differences in testes weights, tubule diameters or gonocyte numbers in any of the treatment groups. For the busulfan study, dose rates of 8 and 16 mg/kg resulted in severe mylosuppression and euthanasia of 7 out of 8 animals between day 12 and 18, whereas animals in the 4mg/kg group showed only mild clinical effects, that were not life threatening. These results indicate that busulfan reduced endogenous spermatogonia in the pre-pubertal ram. This effect is observed at systemic doses of 4 mg/kg or higher; however, doses of 8 mg/kg and above are lethal to the survival of the animal. The use of direct heat (45ºC) or cold (0ºC) to the testes does not affect gonocyte numbers in ram lambs; however, effects on more mature stages was not studied. (1)Brinster RL, Zimmermann JW. (1994) Spermatogenesis following male germ-cell transplantation. Proc Natl Acad Sci USA 91, 11298–11302.