Behaviour was assessed in 32 C57BL/6JCrl and 32 C3H/HeN male mice 1 h following vasectomy; saline or meloxicam was administered 30 min prior to surgery at 5, 10, or 20 mg kg(-1). Faeces were collected 24 h prior to, and 3, 6, 9, 12, 24 h following, vasectomy for measurement of faecal corticosterone. Peak corticosterone levels were significantly higher in mice that underwent vasectomy and received saline (p<0.001) or meloxicam at 5 or 10 mg kg(-1) (p=0.021, and p<0.001, respectively) compared with normal un-operated controls. Mice that underwent vasectomy and received 20 mg kg(-1) meloxicam had peak corticosterone levels that were not different from normal un-operated mice (p=0.254). Discriminant analysis was used to identify behaviours responsible for group separation; these were summed to create two behaviour scores. Score 2 (the frequency of flinching, writhing, rear leg lift and press 2) was thought to be pain related; mice that underwent vasectomy and received saline exhibited significantly more of these behaviours than the normal controls (p=0.032), and the mice that received meloxicam (at any dose). Strain differences were observed in both the stress response to vasectomy and the behavioural changes; the C3H/HeN mice had higher pain scores (behaviour Score 2) and peak corticosterone responses than the C57BL/6JCrl mice. We have demonstrated that significant changes occur in the behaviour of mice following vasectomy, and these changes are reduced by use of meloxicam. Vasectomy elicits a rise in corticosterone levels that was only reduced by the highest dose of meloxicam.

This study evaluated whether the automated behaviour recognition software 'HomeCageScan' (HCS) could detect behaviour changes and any positive analgesic effects in two mouse strains undergoing vasectomy (C3H/HeNCrl and C57BL/6). Another objective was to test the effectiveness of HCS in differentiating between the effects of each treatment relative to conventional manual analysis. Each control (unoperated) group consisted of four mice of each strain. They were either untreated mice, mice given meloxicam alone (10 mg/kg) or mice given either saline or meloxicam (10 mg/kg) 30 min prior to isoflurane anaesthesia. The vasectomized mice received either saline or meloxicam at 5, 10 or 20 mg/kg, again, 30 min prior to isoflurane anaesthesia. Filming began one hour following surgery. Each mouse was filmed for 6 min for the manual analysis and then for a further 20 min for analysis with HCS. In a time-matched test, HCS and the manual analysis produced activity data that generated identical conclusions regarding treatment effects and strain differences. Both HCS and the manual analysis found the C57BL/6 controls were overall more active, but not following vasectomy, when both types of analysis detected markedly reduced activity. Low-dose meloxicam (5 mg/kg) had a positive effect on postoperative mobility in the C3H/HeNCrl mice; however, increasing the dose rate progressively reduced this. These effects were also detected with the manual analysis. Overall, HCS provided a sufficiently accurate and rapid method of analysing mouse behaviour encouraging more prolonged assessments in the future. This capability and the possibility of training the software to recognize a greater range of behaviours, including pain-specific indicators, should be of considerable value for assessing postoperative behaviour in both mice and rats. This would allow analgesic requirements to be investigated in a greater range of rodent models than is currently feasible with conventional analysis methods. Analysing behaviour changes in both experimentally induced and clinical pain states in animals can be an effective means to assess both pain severity and analgesic efficacy. As an integrated response to complex nociceptive stimuli, such analyses offer a more clinically relevant method of assessing analgesic effects than analgesiometry. However, studying behaviour in sufficient detail to detect pain-related behaviour changes and the effects of drugs upon these is extremely time consuming, so studies often only assess a limited range of behaviours, 1,2 or assess for a relatively short time.3 -5 Until recently, automated behavioural analyses have utilized activity monitoring based on infrared technology, 6 simple wheel running 7 or activity recorded via telemetry implants. 8,9 There has recently been a major expansion in the use of genetically-altered mice, and many of these animals require phenotyping to determine the effects of the altered genotype on the animals' physiology, cognition and behaviour. The resources needed to conduct phenotyping te...

Establishing effective cage-side pain assessment methods is essential if post-surgical pain is to be controlled effectively in laboratory animals. Changes to overall activity levels are the most common methods of assessment, but may not be the most appropriate for establishing the analgesic properties of drugs, especially in mice, due their high activity levels. Use of drugs that can affect activity (e.g. opioids) is also a problem. The relative merits of both manual and automated behaviour data collection methods was determined in two inbred mouse strains undergoing vasectomy following treatment with one of 2 buprenorphine dose rates. Body weights and the effects of surgery and buprenorphine on faecal corticosterone were also measured.Surgery caused abnormal behaviour and reduced activity levels, but high dose buprenorphine caused such large-scale increases in activity in controls that we could not establish analgesic effects in surgery groups. Only pain-specific behaviour scoring using the manual approach was effective in showing 0.05 mg/kg buprenorphine alleviated post-vasectomy pain. The C57 mice also responded better to buprenorphine than C3H mice, indicating they were either less painful, or more responsive to its analgesic effects. C3H mice were more susceptible to the confounding effects of buprenorphine irrespective of whether data were collected manually or via the automated approach. Faecal corticosterone levels, although variable, were higher in untreated surgery mice than in control groups, also indicating the presence of pain or distress.Pain-specific scoring was superior to activity monitoring for assessing the analgesic properties of buprenorphine in vasectomised mice. Buprenorphine (0.01 mg/kg), in these strains of male mice, for this procedure, provided inadequate analgesia and although 0.05 mg/kg was more effective, not completely so. The findings support the recommendation that analgesic dose rates should be adjusted in relation to the potential severity of the surgical procedure, the mouse strain, and the individual animals' response.

Vasectomized mice are needed in the production of genetically-modified animals. The BVAAWF/FRAME/RSPCA/UFAW Joint Working Group on Refinement recommended that vasectomy should be performed via an incision in the scrotal sac, rather than via laparotomy, arguing that the former could be less painful due to minimal tissue trauma. This study was undertaken to assess the validity of this recommendation. Mice underwent vasectomy via either abdominal or scrotal approach surgery. Mice were filmed for 15 min presurgery and at one, 24 and 48 h postsurgery. Data were obtained using automated behaviour recognition software (HomeCageScan). Meloxicam was administered either alone or combined with acetaminophen prior to surgery. A third group received only saline subcutaneously. Postsurgery behaviour changes were compared between groups at each time point. Exploratory behaviours such as rearing, walking and sniffing were most greatly reduced at one hour following surgery whereas the duration of grooming increased. By 48 h these changes had largely subsided. Results indicated mice undergoing scrotal approach surgery fared better at one hour postsurgery, but the magnitude of this was relatively insignificant compared with the overall effects of surgery. If the observed behaviour changes resulted from pain, results suggested there was no significant advantage of scrotal versus abdominal approach vasectomy. These and other recently obtained data on the effects of non-steroidal anti-inflammatory drugs (NSAIDs) in mice suggest considerably larger doses of these or more potent analgesics, more precise monitoring of surgical outcomes, or a combination of these factors are needed to determine the extent of pain experienced by mice undergoing vasectomy. Of the total number of animals used in regulated procedures in the UK, genetically-modified animals has increased from 8% (1995) to 54% in 2010. 1 Almost all of these animals were mice, of which a significant proportion being males undergoing vasectomy for inducing pseudopregnancy in females for transgenic animal production. It is presently unknown whether these mice, and those currently involved in these types of studies, experience pain. Despite virtually no supporting evidence the BVAAWF/FRAME/RSPCA/ UFAW Joint Working Group on Refinement 2 recommended vasectomy should be performed via scrotal approach surgery, where the vas deferens could be accessed via a relatively minor incision. By comparison with laparotomy, avoiding incising the abdominal muscles bearing the weight of the viscera (ca. 30% of body mass) 2 was considered likely to be less painful. However, scrotal approach vasectomy also involves dissection and tearing of tissue to access the vas deferens, so significant postoperative pain remains likely.Behavioural analysis is a key method of identifying pain postsurgery in rats and mice. In addition to suppression of normal behaviours including walking and rearing, a range of discrete identifiable acts have been characterized following vasectomy including; belly pressin...