Effects of buprenorphine on acute pain and inflammation in the adjuvant-induced monoarthritis rat model.

Background and aim: Animal modelling of arthritis is often associated with pain and suffering. Severity may be reduced with the use of analgesia which is, however, often withheld due to concerns of introducing a confounding variable. It is therefore important to design and validate pain relief protocols that reduce pain without compromising the scientific objectives. The present study evaluated the effect of buprenorphine analgesia in the immediate post-induction period of an adjuvant-induced monoarthritic rat model. The aim of this study was to extend previous work on refinement of the model by alleviating unnecessary pain. Methods: Male and female Sprague Dawley rats were injected with 20 µl of complete Freund's adjuvant (CFA) into the left ankle. Rats were treated with buprenorphine, either injected subcutaneously or ingested voluntarily, and were compared to rats given subcutaneous injections with vehicle (saline or pure nut paste) or carprofen the first three days post CFA-injection. Measurements of welfare, clinical model-specific parameters and pain-related behaviour were assessed. Results: Buprenorphine, administered either subcutaneously (0.10 or 0.15 mg/kg, twice daily) or by voluntary ingestion in nut paste (1.0 or 3.0 mg/kg, twice daily), improved mobility, stance, rearing and lameness scores significantly 7 h post CFA-injection. Mechanical hyperalgesia peaked at 7 h and was significantly lower in buprenorphine-treated animals, compared to vehicle-treated animals. Joint circumference was highest 24-72 h after CFA injection. Animals treated with buprenorphine did not decrease in joint circumference, opposite carprofen treated animals. Conclusion: Buprenorphine, administered either subcutaneously or by voluntary ingestion, provides adequate analgesia for both sexes within the first 24 h post CFA-injection. Buprenorphine treatment improved clinical scores and appeared not to suppress the inflammatory response. The present study supports previous findings that voluntarily ingested buprenorphine is an effective alternative to repeated injections.

Refinements to captive chimpanzee (Pan troglodytes) care: a self-medication Paradigm.

In an effort to enhance welfare, behavioural management continually refines methods of non-human primate (NHP) care. Chimpanzees (Pan troglodytes) are one of the most cognitively complex captive NHPs and they have been observed to self-medicate in the wild. The population of captive chimpanzees in the US is aged (due to a breeding moratorium instituted in 1998) and will progressively require more medical care as they get older. To functionally simulate natural self-medication behaviour, provide chimpanzees with the opportunity to voluntarily participate in their own healthcare, and open new avenues of communication between caregivers and chimpanzees, we used a medication choice paradigm that allowed chimpanzees to choose their daily arthritis medication. We provided four arthritic, mobility-impaired chimpanzees with meloxicam or ibuprofen in blue or green Gatorade® to establish associations between the coloured drinks and the effects of the medications. We subsequently gave each chimpanzee a choice between the two medications. Behaviour was recorded using 15-min focal animal observations. Mobility was assessed using interactive mobility tests and a caregiver-rating system. One chimpanzee showed a medication preference (ibuprofen over meloxicam). The chimpanzees exhibited no significant behavioural or mobility differences over time, suggesting that ibuprofen and meloxicam may not differ significantly in their ability to alleviate arthritic symptoms. Whether or not the chimpanzees show a medication preference, the opportunity to make meaningful choices and the functional simulation of a complex behaviour, self-medication, is present when using this medication choice technique. Furthermore, the paradigm itself could have potential applications for additional medication options and treatment regimens.

Low socio-economic status is a newly identified independent risk factor for poor vitamin D status in severely obese adults.

BACKGROUND: Hypovitaminosis D is very prevalent, especially in the obese population. However, the degree of severity and the parameters involved in vitamin D deficiency in this population are still unclear. The present study aimed to identify, from among the factors known to influence vitamin D status in a healthy population, those impacting the same parameter in obese population. METHODS: Serum 25-OH-D concentration was measured in 564 patients with class III obesity [i.e. severe and morbid obesity; mean (SD) body mass index (BMI) 42.04 (6.92) kg m-2 ] and their demographic, clinical, biological, anthropometric, dietary and socio-economic data were collected. RESULTS: We observed that 96% of the obese patients had serum 25-OH-D lower than 30 ng mL-1 . Severe vitamin D deficiency (serum 25-OH-D concentration <10 ng mL-1 ) affected 35% of this population. We found an inverse relationship between 25-OH-D levels and BMI (P = 0.012), fat mass (P = 0.041), metabolic syndrome (P < 0.0001), fasting blood glucose (P = 0.023), homeostasis model assessment for insulin resistance (P = 0.008), waist circumference (P = 0.001), and fasting blood triglycerides (P = 0.002) and C-reactive protein (P = 0.005). Low socio-economic status independently increased the risk of severe vitamin D deficiency [odds ratio (OR) = 1.98; 95% confidence interval (CI) 1.25-3.13], especially in the autumn-winter season (OR = 2.94; 95% CI 1.98-4.36), morbid obesity (OR = 3.19; 95% CI 1.49-6.82), metabolic syndrome (OR = 1.6; 95% CI 1.06-2.42) and inflammation (OR = 1.03; 95% CI 1.01-1.06). CONCLUSIONS: Vitamin D deficiency is extremely common among obese patients, and the prevalence of severe deficiency is high. The association of adiposity, high body mass index, metabolic syndrome and inflammation with vitamin D status is marked, whereas low socio-economic status appears to be a major risk factor for severe vitamin D deficiency, suggesting that vitamin D deficiency may at least in part be responsible for the greater health vulnerability of populations with low socio-economic status.

The applicability of a gel delivery system for self-administration of buprenorphine to laboratory mice.

Oral administration of perioperative analgesia to laboratory mice is beneficial compared with administration by injection. The mice become less stressed when allowed to voluntarily ingest the drug in a palatable feed item and it results in high and long-lasting serum concentrations of the drug. We have previously demonstrated sticky nut and chocolate paste to be well-liked by mice and readily ingested in most cases. However, a disadvantage with nut and chocolate paste is its high content of fat and sugar, which may have undesirable effects in some experimental models. Alternatively, a delivery system using an aqueous gel may serve as a supplementary source of fluid post-operatively and as a vehicle for analgesic drugs. In the present study, we investigated the willingness of the mice to ingest a commercially available gel, by measuring the duration from introduction of the gel to first ingestion, as well as the amount ingested overnight. Furthermore, buprenorphine in two different concentrations (5 and 15 µg/mL) was mixed in the gel and the resulting serum concentrations of buprenorphine were investigated. The aqueous gel was ingested by the mice, but their willingness was low and did not increase over time. The serum concentrations of buprenorphine were similar to, or higher than, those following a subcutaneous injection (0.1 mg/kg body weight), but the variation was considerably higher. In conclusion, aqueous gel may serve as a relevant vehicle for the voluntary ingestion of buprenorphine in mice, but the willingness of the mice to ingest the gel needs to be improved.

Delayed response task performance as a function of age in cynomolgus monkeys (Macaca fascicularis).

We compared delayed response task performance in young, middle-aged, and old cynomolgus monkeys using three memory tests that have been used with non-human primates. Eighteen cynomolgus monkeys--6 young (4-9 years), 6 middle-aged (10-19 years), and 6 old (above 20 years)--were tested. In general, the old monkeys scored significantly worse than did the animals in the two other age groups. Longer delays between stimulus presentation and response increased the performance differences between the old and younger monkeys. The old monkeys in particular showed signs of impaired visuo-spatial memory and deteriorated memory consolidation and executive functioning. These results add to the body of evidence supporting the utility of Macaca fascicularis in studies of cognition and as a potential translational model for age-associated memory impairment/dementia-related disorders.

Correlations between serum levels of beta amyloid, cerebrospinal levels of tau and phospho tau, and delayed response tasks in young and aged cynomolgus monkeys (Macaca fascicularis).

BACKGROUND: In an attempt to explore cynomolgus monkeys as an animal model for Alzheimer's disease, the present study focused on the Alzheimer's biomarkers beta amyloid 1-42 (Aß42 ) in serum, and total tau (t-tau) and phosphorylated tau (p-tau) levels in cerebrospinal fluid. METHODS: We measured biomarker levels in Young and Aged cynomolgus monkeys and correlated these with performance on three delayed response tasks. RESULTS: The Aß42 concentration of the Aged monkeys was significantly lower than in the Young subjects, while the t-tau and p-tau did not significantly differ between the groups. The Young subjects performed significantly better than the Aged individuals on the memory tests. Only Aß42 levels were significantly correlated with performance in the three delayed response tasks. CONCLUSIONS: Circulating Aß42 levels were lower in Aged monkeys and were correlated with inferior performance on delayed response tasks in Aged animals; therefore, both measures may be useful in establishing cynomolgus monkeys as models for studies of AD.

Physiological and behavioural stress responses in cynomolgus macaques (Macaca fascicularis) to noise associated with construction work.

The aim of the present study was to evaluate the behavioural and physiological responses to environmental disturbances (live and recorded dynamite explosions) in laboratory non-human primates in preparation for a future tunnel construction underneath our animal facility. In a pilot study (A) on 20 female Macaca fascicularis, a day of test blasts resulted in an increase in faecal cortisol and immunoreactive cortisol metabolites (CICM), and the animals reacted behaviourally with vertical flight and vocalizations. In a follow-up study (B), we assessed the impact of 10 days of exposure to recorded detonations on the behaviour and CICM in 16 M. fascicularis. In the latter study we introduced a predictive signal, serving as a conditional stimulus, to half of the animals. We found no significant effects of the noise in the Signal group; while the Control groups' CICM values were affected. The behaviour was largely unaffected in the two groups. It was decided not to introduce a research moratorium on biomedical research planned to be conducted during the future tunnel construction, and that a conditional stimulus ('warning signal') will be used.

Space use selectivity by chimpanzees and gorillas in an indoor-outdoor enclosure.

Understanding the relationship between physical environments and nonhuman primate behavior is a key element for effective care and management in a range of settings. The physical features of the captive environment, including not only gross useable space but also environmental complexity, can have a significant influence on primate behavior and ultimately, animal welfare. But despite this connection, there remains relatively little conclusive data on how captive primates, especially great apes, use the spaces provided to them, especially in modern, indoor-outdoor enclosures that have become more prevalent in recent years. In this study, we used four years of detailed data on where 23 great apes (chimpanzees and gorillas) positioned themselves within a modern, indoor-outdoor zoo enclosure to determine not only how the apes utilized their space but also how access to outdoor areas affected their spatial selectivity. We found that both species used relatively little of their available space: chimpanzees and gorillas spent half their time in only 3.2 and 1.5% of their useable three-dimensional space, respectively. Chimpanzees utilized the outdoor space more than gorillas, but access to the outdoors did not affect space selectivity in the indoor area for either species. Although both species of ape were highly selective in their space use, consideration should be given to the importance of providing the choice to locate in a variety of spaces, including outdoor areas. These data represent an extremely detailed account of space selectivity by great apes in an indoor-outdoor environment and have substantial implications for future facility design and captive primate management.

The effect of environmental enrichment on the behavior of captive tufted capuchin monkeys (Cebus apella).

The authors provided different forms of environmental enrichment to six old laboratory male tufted capuchin monkeys (Cebus apella) and studied the behavior of the monkeys during a baseline period and during three enrichment periods. Each observation period lasted 5 d, with an interval of 6 d between periods. During the first enrichment period, the authors provided Buster cubes and wood cylinders with drilled holes filled with gum arabic. During the second enrichment period, monkeys were provided with a deep litter of bark shavings, and during the third enrichment period, they were given Buster cubes, wood cylinders and bark shavings. When provided with enrichment, the monkeys engaged in natural, species-specific activities and began to exhibit behavioral profiles that more closely resembled those of their natural counterparts. This suggests that their psychological well-being had improved and that group housing combined with environmental enrichment can improve the welfare of old laboratory tufted capuchin monkeys that were previously housed individually.

Ape behavior in two alternating environments: comparing exhibit and short-term holding areas.

In many facilities, primates are voluntarily transferred between different enclosures on a daily basis to facilitate animal husbandry and exhibit maintenance. This procedure is particularly relevant in the management of great apes living in zoos, where the requirements of functional management must be balanced with the desire to maintain enriching and naturalistic exhibit enclosures that benefit ape residents and attract the visiting public. In these settings, examinations of ape behavior and welfare typically focus exclusively on activity in the primary exhibit area. However, physical, social and sensory experiences unique to each area may shape different patterns of behavior. In the current study, zoo-living chimpanzees and gorillas were moved each day from exhibit areas to off-exhibit holding areas for a short duration as a part of regular management procedures. Behavioral data indicated species-specific reactions to the holding area, including increased aggression and self-directed behavior by chimpanzees and increased activity and prosocial behavior among gorilla subjects. Both species showed more feeding-foraging behavior while in the exhibit enclosure. Results suggest that holding areas may not meet all behavior needs of captive great apes and demonstrate the importance of including all components of the captive enclosure in comprehensive analyses of great ape behavior and welfare.

Impact of surgical severity and analgesic treatment on plasma corticosterone in rats during surgery.

Tissue injury and anaesthesia during surgery induce a stress response associated with increased glucocorticoid secretion from the adrenal glands. This response alters the normal physiology and may cause postoperative morbidity, as well as affect the results during acute experiments. The aim of the present investigation was to study the effect of surgical severity and analgesic treatment on circulating corticosterone in male Sprague-Dawley rats. Male rats were treated with either lidocaine infiltrated during surgery, buprenorphine (0.05 or 0.1 mg/kg subcutaneously) or saline subcutaneously. Each treatment group was subjected to either arterial catheterisation or arterial catheterisation and laparotomy. A catheter was inserted in the common carotid artery and blood was collected during surgery and during anaesthesia 6 h after surgery. Lidocaine treatment reduced the corticosterone levels compared to saline treatment after catheterisation but not after laparotomy. Buprenorphine treatment reduced the corticosterone levels during the first hour after surgery after both catheterisation and laparotomy. The higher buprenorphine dose led to an earlier and more pronounced reduction, especially after laparotomy. In the present study, the corticosterone response during surgery in laboratory rats is correlated with the severity of the procedure, and buprenorphine reduces the surgical stress response more effectively than lidocaine treatment.

Impact of aspen furniture and restricted feeding on activity, blood pressure, heart rate and faecal corticosterone and immunoglobulin A excretion in rats (Rattus norvegicus) housed in individually ventilated cages.

This study aims to evaluate the impact of adding different items in individually ventilated rat cages on the animal's activity, cardiovascular parameters and faecal stress indicators. The following three cage items made of aspen were compared: a cross made of two intersecting boards, a similar cross where drilled holes were loaded with food pellets (restricted feeding) and a rectangular tube. Male rats of the strains BN and F344 (n = 12) were housed in groups of three; one rat in each group was implanted with a telemetric transponder to measure mean arterial pressure (MAP) and heart rate (HR). In a crossover design, each group spent 14 days with each type of cage furniture, thereafter faecal pellets were collected for faecal analyses. The means of activity and means and coefficient of variation for MAP and HR were calculated for days 2, 6, 10 and 14. As a way of determining which of the statistically significant MAP and HR mean changes were biologically meaningful, the night-day differences of the controls on day 14 were used. Both board types lowered MAP of F344 rats; hence dividing walls seem beneficial for F344 welfare. None of the MAP or HR differences in BN rats were biologically significant. No statistically significant differences in faecal corticosterone or IgA excretion were detected. In conclusion, provision of general recommendations with respect to cage furniture for rat cages is complicated because there is a clear genetic component involved in how animals respond to these structures.

Immunospecific immunoglobulins and IL-10 as markers for Trypanosoma brucei rhodesiense late stage disease in experimentally infected vervet monkeys.

OBJECTIVE: To determine the usefulness of IL-10 and immunoglobulin M (IgM) as biomarkers for staging HAT in vervet monkeys, a useful pathogenesis model for humans. METHODS: Vervet monkeys were infected with Trypanosoma brucei rhodesiense and subsequently given sub-curative and curative treatment 28 and 140 days post-infection (dpi) respectively. Matched serum and CSF samples were obtained at regular intervals and immunospecific IgM, immunoglobulin G (IgG) and IL-10 were quantified by ELISA. RESULTS: There was no detectable immunospecific IgM and IgG in the CSF before 49 dpi. CSF IgM and IgG and serum IgM were significantly elevated with peak levels coinciding with meningoencephalitis 98 dpi. The serum IL-10 was upregulated in both early and late disease stage, coinciding with primary and relapse parasitaemia respectively. CSF white cell counts (CSF WCC) were elevated progressively till curative treatment was given. After curative treatment, there was rapid and significant drop in serum IgM and IL-10 concentration as well as CSF WCC. However, the CSF IgM and IgG remained detectable to the end of the study. CONCLUSIONS: Serum and CSF concentrations of immunospecific IgM and CSF IgG changes followed a pattern that mimics the progression of the disease and may present reliable and useful biomarkers of the disease stage. Due to rapid decline, serum IgM and IL-10 are, additionally, potential biomarkers of the success of chemotherapy.

Comparison of the efficacy and safety of a novel meloxicam ophthalmic formulation with a reference diclofenac solution in cataract surgery.

A novel topical ophthalmic formulation of the preferential COX-2 inhibitor meloxicam has recently been developed. The purpose of the present study was to evaluate the efficacy and safety of this novel 0.03% meloxicam solution with regard to a reference 0.1% diclofenac formulation in a prospective, parallel, randomized, multicenter, double-blind study. Two groups of patients submitted to phacoemulsification with intraocular lens implantation were formed. Patients in one group were treated with meloxicam and those in the other group with diclofenac. Dosing was 1 drop t.i.d. for 30 days, beginning the first day after surgery, for both treatments. Inflammation was assessed by the presence of cells in the anterior chamber, anterior chamber flare, ciliary flush, photophobia and pain. Both treatments significantly reduced these indicators. Topical meloxicam and diclofenac produced a similar degree of burning sensation and conjunctival hyperemia. There was no significant difference between treatments in any of the measured parameters. It is concluded that the novel meloxicam solution is effective and safe. Meloxicam, however, did not offer any significant benefit over the diclofenac formulation in patients submitted to cataract surgery.

The diet board: welfare impacts of a novel method of dietary restriction in laboratory rats.

Laboratory rats are commonly fed ad libitum (AL). Moderate dietary restriction (DR) decreases mortality and morbidity when compared with AL feeding, but there are several obstacles to the implementation of DR. Traditional methods of restricted feeding disrupt normal diurnal eating rhythms and are not compatible with group housing. We have designed a novel method, the diet board, to restrict the feeding of group-housed rats. Animals fed from the diet board had 15% lower body weight than the AL-fed animals at the age of 17 weeks. The welfare effects of diet board feeding were assessed by comparing the stress physiology of diet board fed animals with that of AL-fed animals. Diet board feeding was associated with higher serum corticosterone levels and lower faecal secretion of IgA, suggesting the diet board causes a stress reaction. However, the AL-fed group had larger adrenal glands with higher adrenaline and noradrenaline content than the diet board animals. No gastric ulcers were found in any of the animals at necropsy. The diet board thus appears to cause a stress reaction when compared with AL-fed rats, but no apparent pathology was associated with this reaction. The diet board could help to solve the health problems associated with AL feeding, while allowing the rats to be group-housed and to maintain their normal diurnal eating rhythms. The diet board can also be seen as a functional cage furniture item, dividing the cage into compartments and thus increasing the structural complexity of the environment. In conclusion, the diet board appears to possess refinement potential compared with traditional methods of DR.

Effect of subcutaneous injection and oral voluntary ingestion of buprenorphine on post-operative serum corticosterone levels in male rats.

BACKGROUND: Adequate peri-operative analgesia may reduce post-operative stress response and improve recovery in laboratory animals. We have established a method involving repeated automated blood sampling, allowing quantification of serum corticosterone levels in rats for stress assessment without stress-inducing handling or restraint. In the present study, the effects of the commonly used route of buprenorphine administration (0.05 mg/kg injected subcutaneously) were compared with oral administration (0.4 mg/kg mixed with Nutella and orally administered by voluntary ingestion) in male Sprague-Dawley rats. METHODS: A catheter was placed in the jugular vein and attached to an Accusampler for automated blood sampling. During 96 h after surgery, blood was collected at specified time points. Pre- and post-operative body weights and water consumption were registered. RESULTS: Buprenorphine significantly suppressed levels of circulating corticosterone after the oral but not after the subcutaneous treatment. Both buprenorphine treatments had a positive impact on maintenance of body weight and water consumption, compared to the control group that received no buprenorphine. CONCLUSION: The present investigation suggests that oral voluntary ingestion ad libitum is an efficacious, convenient and non-invasive way of administering peri-operative buprenorphine to rats, as judged by corticosteroid response and effects on body weight and water consumption.

Stress in cynomolgus monkeys (Macaca fascicularis) subjected to long-distance transport and simulated transport housing conditions.

The stress associated with transportation of non-human primates used in scientific research is an important but almost unexplored part of laboratory animal husbandry. The procedures and routines concerning transport are not only important for the animals' physical health but also for their mental health as well. The transport stress in cynomolgus monkeys (Macaca fascicularis) was studied in two experiments. In Experiment 1, 25 adult female cynomolgus monkeys were divided into five groups of five animals each that received different diets during the transport phase of the experiment. All animals were transported in conventional single animal transport cages with no visual or tactile contact with conspecifics. The animals were transported by lorry for 24 h at ambient temperatures ranging between 20 degrees C and 35 degrees C. Urine produced before, during and after transport was collected and analysed for cortisol by enzyme-linked immunosorbent assay (ELISA). All monkeys exhibited a significant increase in cortisol excretion per time unit during the transport and on the first day following transport.Although anecdotal reports concerning diet during transport, including the provision of fruits and/or a tranquiliser, was thought likely to influence stress responses, these were not corrobated by the present study. In Experiment 2, behavioural data were collected from 18 cynomolgus macaques before and after transfer from group cages to either single or pair housing, and also before and after a simulated transport, in which the animals were housed in transport cages. The single housed monkeys were confined to single transport cages and the pair housed monkeys were kept in their pairs in double size cages. Both pair housed and singly housed monkeys showed clear behavioural signs of stress soon after their transfer out of their group cages.However, stress-associated behaviours were more prevalent in singly housed animals than in pair housed animals, and these behaviours persisted for a longer time after the simulated transport housing event than in the pair housed monkeys. Our data confirm that the transport of cynomolgus monkeys is stressful and suggest that it would be beneficial for the cynomolgus monkeys to be housed and transported in compatible pairs from the time they leave their group cages at the source country breeding facility until they arrive at their final laboratory destination in the country of use.