Blood collection from the sublingual vein in mice and hamsters: a suitable alternative to retrobulbar technique that provides large volumes and minimizes tissue damage.

Blood examination is a key element in studies of laboratory animals. In rodents, retrobulbar venous plexus puncture is a commonly used method for obtaining a blood sample. Although this technique yields large volumes of blood, the disadvantage is that it can lead to severe tissue damage. The aim of the present study was to develop the puncture of V. sublingualis as a suitable alternative technique for drawing blood in mice and other rodents. In rats, this method has been established for collecting large blood volumes. During the first part of the study, the sublingual bleeding technique was developed for use in mice and hamsters. Guinea pigs, however, do not have a sublingual vein; therefore, in this species the method is not possible. In the second part of the study, retrobulbar and sublingual methods were compared using male CD-1 mice. When compared with the retrobulbar method, sublingual venepuncture showed less tissue destruction in mice, with a decreased mean severity in the histological examination. In conclusion, sublingual venepuncture can be recommended as a suitable, alternative blood collection technique, because of the reduced risk of tissue damage in mice and hamsters.

What the literature tells us about score sheet design.

Score sheets are an essential tool of animal welfare. They allow transparent assessments to be made of animal health and behavior during animal experiments and they define interventions when deviations from normal status are detected. As such, score sheets help to refine animal experiments as part of the 3R (replacement, reduction and refinement) concept. This mini review aims at summarizing the scarce literature available on score sheet design.

Sublingual and submandibular blood collection in mice: a comparison of effects on body weight, food consumption and tissue damage.

In a large number of animal experiments, blood collection is crucial for achieving the study aim. Requirements on sampling techniques used include their practicability, their effectiveness in terms of obtaining the desired blood volume, sample quality and low impact on animal's wellbeing. Numerous methods for blood collection from mice have been published. For large blood volumes, submandibular and sublingual bleeding was developed as alternatives to the retrobulbar bleeding method, which is considered controversial as it results in severe tissue damage. Only a few studies report the use of submandibular and sublingual techniques in mice. In particular, the degree of tissue damage or influence on animal's wellbeing due to submandibular bleeding in conscious mice has not yet been clearly assessed. This gap in the knowledge base has been filled by our exploratory study that revealed clear differences between both techniques. Defence movements during submandibular blood collection in conscious mice resulted in more complications and revealed insufficient blood sample quality due to the prolonged duration of blood collection. In addition, it is likely that these movements may have caused lesions to be more pronounced. Changes in red blood cell parameters (red blood cell count, haemoglobin and haematocrit), in glucose and in total protein concentrations observed in anaesthetized animals were most likely related to anaesthesia. Sublingually punctured mice gained significantly more body weight than submandibularly punctured mice, likely due to less severe tissue lesions and improved healing processes. Based on these results, we recommend the sublingual blood collection technique to be used in mice. However, if the submandibular bleeding technique is used, it should be performed in anaesthetized mice only.