Lars Friis Mikkelsen

Fasting of mice: a review.

Fasting of mice is a common procedure performed in association with many different types of experiments mainly in order to reduce variability in investigatory parameters or to facilitate surgical procedures. However, the effects of fasting not directly related to the investigatory parameters are often ignored. The aim of this review is to present and summarize knowledge about the effects of fasting of mice to facilitate optimization of the fasting procedure for any given study and thereby maximize the scientific outcome and minimize the discomfort for the mice and hence ensure high animal welfare. The results are presented from a number of experimental studies, providing evidence for fasting-induced changes in hormone balance, body weight, metabolism, hepatic enzymes, cardiovascular parameters, body temperature and toxicological responses. A description of relevant normal behaviour and standard physiological parameters is given, concluding that mice are primarily nocturnal and consume two-thirds of their total food intake during the night. It is argued that overnight fasting of mice is not comparable with overnight fasting of humans because the mouse has a nocturnal circadian rhythm and a higher metabolic rate. It is suggested that because many physiological parameters are regulated by circadian rhythms, fasting initiated at different points in the circadian rhythm has different impacts and produces different results.

Quality of plasma sampled by different methods for multiple blood sampling in mice

For oral glucose tolerance test (OGTT) in mice, multiple blood samples need to be taken within a few hours from conscious mice. Today, a number of essential parameters may be analysed on very small amounts of plasma, thus reducing the number of animals to be used. It is, however, crucial to obtain high-quality plasma or serum in order to avoid increased data variation and thereby increased group sizes. The aim of this study was to find the most valid and reproducible method for withdrawal of blood samples when performing OGTT. Four methods, i.e. amputation of the tail tip, lateral tail incision, puncture of the tail tip and periorbital puncture, were selected for testing at 21°C and 30°C after a pilot study. For each method, four blood samples were drawn from C57BL/6 mice at 30 min intervals. The presence of clots was registered, haemolysis was monitored spectrophotometrically at 430 nm, and it was noted whether it was possible to achieve 30–50 μL blood. Furthermore, a small amount of extra blood was sampled before and after the four samplings for testing of whether the sampling induced a blood glucose change over the 90 min test period. All methods resulted in acceptable amounts of plasma. Clots were observed in a sparse number of samples with no significant differences between the methods. Periorbital puncture did not lead to any haemolysed samples at all, and lateral tail incision resulted in only a few haemolysed samples, while puncture or amputation of the tail tip induced haemolysis in a significant number of samples. All methods, except for puncture of the tail tip, influenced blood glucose. Periorbital puncture resulted in a dramatic increase in blood glucose of up to 3.5 mmol/L indicating that it is stressful. Although lateral tail incision also had some impact on blood glucose, it seems to be the method of choice for OGTT, as it is likely to produce a clot-free non-haemolysed sample, while periorbital sampling, although producing a high quality of sample, induces such a dramatic change in blood glucose that it should not be applied for OGTT in mice.

Study on biological variability of five acute-phase reactants in dogs

The analytical, within-dog and between-dog components of variation were estimated for serum iron, plasma fibrinogen, serum C-reactive protein, serum α1-acid glycoprotein and serum haptoglobin, and used to 1) estimate the critical difference for significance between serial results; 2) assess the utility of conventional population-based reference ranges; and 3) set objective analytical performance standards for each quantity. Blood was sampled weekly from eight clinically healthy Beagle dogs for 5 weeks. Results were analysed for outliers and subsequently subjected to nested analysis of variance to obtain the components of variance. All quantities showed a degree of individuality, which can make the use of conventional population-based reference ranges alone an insensitive interpretative criterion. The critical difference needed for significance between serial results makes an objective criterion for monitoring individuals, and are useful for dogs where serial results are available for comparison. Desirable analytical imprecision was met for all quantities except for serum α1-acid glycoprotein, where improvement is warranted. Objective analytical performance standards for inaccuracy and total error were set up for each quantity.

Canine serum C‐reactive protein as a quantitative marker of the inflammatory stimulus of aseptic elective soft tissue surgery

BACKGROUND C-reactive protein (CRP) is an established serum marker for the presence of systemic inflammation in dogs. Results from previous experimental and clinical studies suggest that CRP concentrations also quantitatively reflect the degree and progress of an inflammatory process, suggesting its use for inflammation monitoring. OBJECTIVES The objective was to investigate whether the canine CRP response in serum correlates with the amount of trauma and the consequent inflammatory response after 3 standard aseptic soft-tissue surgical procedures in 3 groups of dogs. METHODS A total of 24 client-owned intact female dogs of various breeds were enrolled in a clinical study with random allocation into 2 surgical groups, for either conventional, open-approach ovariohysterectomy (OVH; n = 14) or laparoscopic assisted OVH (n = 10). In addition, a group of 8 male Beagles from a laboratory animal facility underwent vasectomy, serving as the third and mildest surgical trauma group. Serum CRP was measured pre- and at 4, 8, 12, 23, and 27 hours postsurgery. Cumulative concentration over time and point concentrations of CRP were correlated with the surgical trauma impact level. RESULTS There was a significant surgery trauma-related difference in cumulative CRP concentrations among the 3 groups, and also in the 12 hours postsurgery concentration. CONCLUSION The CRP response varied according to the degree of surgical trauma on 3 standardized levels, thus supporting the use of canine serum concentrations of CRP as an inflammatory activity indicator and monitoring marker.

Impact of blood sampling technique on blood quality and animal welfare in haemophilic mice.

Blood collection in mice can be a challenge, in particular for samples used for coagulation analysis as initiation of coagulation during the procedures can influence the results. Blood collection from the retrobulbar venous plexus is commonly used but the method remains controversial. Several alternatives exist but not all are applicable to mice with a compromised coagulation system because of subsequently excessive bleeding. We therefore wanted to explore whether blood collection by puncture of the submandibular vein could replace blood collected from the retrobulbar venous plexus during pharmacokinetic and pharmacodynamic studies in mice lacking coagulation factor VIII (FVIII). The plasma concentrations of recombinant activated factor VII were independent of the blood collection method in a pharmacokinetic study. The same applied to the thromboelastographic profile of mice with normal coagulation in a pharmacodynamic study. However, excessive haemorrhages were observed in all FVIII knockout mice after a single puncture of the submandibular vein and 60% of the mice were euthanized 2–4 h after the blood collection. In contrast, no or only slight haemorrhage was observed in animals subjected to blood collection from the retrobulbar venous plexus. No signs of distress determined by blood glucose level or clinical abnormalities of the eye were observed after puncture of the retrobulbar venous plexus. In conclusion, blood collected by puncture of the submandibular vein and retrobulbar venous plexus has a quality which allows it to be used in coagulation assays. However, because of excessive bleedings, puncture of the submandibular vein is not recommended in mice lacking FVIII.