Among small laboratory animals, mice (Mus musculus) are the most popular animal model in biomedical research because of their biological similarity to man, reduced maintenance cost, easy handling, short reproduction rate, and their use in genetic manipulation studies. Experimental procedures on animals often require anesthesia and/or analgesia to obtain adequate immobilization and to reduce stress or pain, not only for ethical reasons but also because of their potentially adverse effects on experimental results. Infact, anesthetic and analgesic agents may influence physiological parameters, potentially interfering with research models. Under these circumstances, it is of paramount importance to refine animal experiments and to use highly sophisticated anesthetic procedures that include systemic and local analgesia, sedation, chemical restraint, and both trained and dedicated personnel. Mice imaging procedures are increasingly used in preclinical research because they allow in vivo monitoring and they are readily available for longitudinal and noninvasive studies as well as investigations into the evolution of diseases and the effects of new therapies. The choice of a suitable anesthetic procedure is a key factor in preclinical imaging studies, and should comply with the imaging technique, the procedure length, and the aim of the study. We reviewed the existing literature on molecular imaging studies in mice, describing the effects of different anesthetic protocols, and reported our experience with such studies. We found that preanesthetic care reduces the incidence of complications that can occur in the course of anesthesia. In mice, strain, body weight, age, and sex add to the well-known anesthetic variability that exists among individuals of other species. Mice anesthesia was proved tricky for several reasons including the small animals’ size, metabolic rate, and the high risk of hypothermia and hypoglycemia. Several murine models that mimic human diseases such as obesity, diabetes mellitus, myocardial ischemia, and neoplasia require specific anesthetic protocols and pose increasing difficulties in serial studies. Furthermore, genome alterations of transgenic mice can influence the effects of anesthetic agents. Sometimes imaging procedures entail slightly painful or invasive procedures such as intracavitary or intravascular injections, blood vessel catheterization, or microinjections in target organs. Under these cases, we showed that it is important to carefully monitor and support mice body temperature, heart and respiratory rates, prevent surgical field infections by maintaining aseptic surgical conditions in combination with the use of local or systemic antibiotics, and to adopt an adequate analgesic protocol. Moreover, supportive care with fluid theraphy, a warm, dry, and quiet environment with an oxygen-enriched atmosphere may be also recommended in some experiments. We concluded that mice anesthesia and animal care demand a deep knowledge of the physiology and pharmacology of this species. According to the aims of experimental procedure, anesthetic protocol should be tailored by the use of tranquilizers, injectable/inhalation anesthetics and analgesics. Patient monitoring and post-operative care reduce the rate of complications, improving animal welfare and experimental results. Additional studies are needed for a better refinement of animal handling and anesthesia, for optimizing the results of imaging techniques, and for simultaneously improving animal welfare.

S. Gargiulo*, M. Gramanzini*, Liuzzi R, Greco A, Brunetti A, Vesce G, “Effects of some anesthetic agents on skin microcirculation evaluated by laser Doppler perfusion imaging in mice”, BMC Veterinary Research 2013 Dec 17; 9(1):255. doi: 10.1186/1746-6148-9-255. * equal contribution

A. Greco, M. Mancini, S. Gargiulo, M. Gramanzini, PP. Claudio, A. Brunetti, M. Salvatore, “Ultrasound Biomicroscopy in Small Animal Research: Applications in Molecular and Preclinical Imaging”, Journal of Biomedicine and Biotechnology 2012; doi:10.1155/2012/519238.

S. Gargiulo, A. Greco, M. Gramanzini, S. Esposito, A. Affuso, A. Brunetti, G. Vesce, “Mice Anesthesia, Analgesia, and Care, Part I: Anesthetic Considerations in Preclinical Research”, ILAR Journal 2012 Mar,  Volume 53, Issue 1, pp 55-69.

S. Gargiulo, A. Greco, M. Gramanzini, S. Esposito, A. Affuso, A. Brunetti, G. Vesce, “Mice Anesthesia, Analgesia, and Care, Part II: Special Considerations for Preclinical Imaging Studies”, ILAR Journal 2012 Mar, Volume 53, Issue 1, pp 70-81.  

S. Gargiulo, M. Gramanzini, P. Gisonni, G. Vesce, M. Mancini. Hemodynamic effects of some sedative drugs in traslational murine models. SIARTIVet 2015, May 25-26, Naples, Italy.

S. Gargiulo, M. Gramanzini, P. Gisonni, G. Vesce, A. Brunetti and M. Salvatore, “High resolution echocardiographic evaluation of hemodynamic effects of anesthetics in mice”, EMIM 2014, June 4-6, 2014, Stadsschouwburg Antwerp, Belgium.

M. Gramanzini, S. Gargiulo, A. Greco A. Brunetti, “Analgesic treatment in High Resolution Ultrasound (HRU) guided in utero micro-injection in laboratory mouse”, AISAL 2013, 18-19 ottobre, Imola, Italia. (Comparative Medicine Vol 63, No 6, December 2013, Pages 537-542).

S. Gargiulo, M. Gramanzini, A. Greco, A. Brunetti, “Analgesic treatment in a MCAO mouse model”, AISAL 2013, 18-19 ottobre, Imola, Italia, (Comparative Medicine Vol 63, No 6, December 2013, Pages 537-542).

S. Gargiulo, M. Gramanzini,  A. Greco,  A. Brunetti, G. Vesce, “The effects of some anesthetic agents on microcirculation evaluated by Laser Doppler Perfusion Imaging (LDPI) in mice”, LXVII Convegno SISVET-Brescia 17-19 Settembre 2013.

A. Greco, S. Gargiulo, M. Gramanzini, LM. Pizzuti, M. Mancini, A. Brunetti, “Feasibility of High-Resolution Ultrasound guided Microinjection in mice uterus”, Simposio AISAL 2010, 4-5 novembre 2010 Imola, Italia. (Comparative Medicine Vol 60, No 6, December 2010).

A. Greco, S. Gargiulo, B. Lamagna, M. Gramanzini, L. Meomartino, A. Brunetti, “Imaging e manipolazione di embrioni di topo in utero guidata dall’ecografia ad alta risoluzione”, Atti SICV 2010, Olbia, Italia.