Orbital bleeding in rats while under diethylether anaesthesia does not influence telemetrically determined heart rate, body temperature, locomotor and eating activity when compared with anaesthesia alone

The question addressed was whether orbital bleeding in rats, while under diethylether anaesthesia, affects their locomotor activity, body core temperature, heart rate rhythm and eating pattern. Roman High Avoidance (RHA) and Roman Low Avoidance (RLA) rats were used to enhance generalization of the results. Orbital bleeding when the rats were under diethylether anaesthesia was compared with diethylether anaesthesia alone. To take into account any effects of handling, the rats were also subjected to sham anaesthesia. The RHA rats urinated more during anaesthesia, needed more time to recover from the anaesthesia and showed a greater endocrine stress response to diethylether anaesthesia when compared with the RLA rats. During anaesthesia, the RHA rats showed a greater fall of body temperature and bradycardia than did the RLA rats. Diethylether anaesthesia reduced locomotor activity in the RHA rats, but had no effect in the RLA rats. In neither RHA nor RLA rats did anaesthesia plus orbital puncture, versus anaesthesia alone, influence body temperature, heart rate rhythm, locomotor and eating activity. The lack of effect of orbital puncture occurred both in the short term (within 2 h) and long term (within 48 hours) and thus this study indicates that orbital puncture had, at least with respect to variables measured in the present study, no effect superimposed on that of diethylether anaesthesia

Identification of Srp9 as a febrile seizure susceptibility gene

Objective: Febrile seizures (FS) are the most common seizure type in young children. Complex FS are a risk factor for mesial temporal lobe epilepsy (mTLE). To identify new FS susceptibility genes we used a forward genetic strategy in mice and subsequently analyzed candidate genes in humans. Methods: We mapped a quantitative trait locus (QTL1) for hyperthermia-induced FS on mouse chromosome 1, containing the signal recognition particle 9 (Srp9) gene. Effects of differential Srp9 expression were assessed in vivo and in vitro. Hippocampal SRP9 expression and genetic association were analyzed in FS and mTLE patients. Results: Srp9 was differentially expressed between parental strains C57BL/6J and A/J. Chromosome substitution strain 1 (CSS1) mice exhibited lower FS susceptibility and Srp9 expression than C57BL/6J mice. In vivo knockdown of brain Srp9 reduced FS susceptibility. Mice with reduced Srp9 expression and FS susceptibility, exhibited reduced hippocampal AMPA and NMDA currents. Downregulation of neuronal Srp9 reduced surface expression of AMPA receptor subunit GluA1. mTLE patients with antecedent FS had higher SRP9 expression than patients without. SRP9 promoter SNP rs12403575(G/A) was genetically associated with FS and mTLE. Interpretation: Our findings identify SRP9 as a novel FS susceptibility gene and indicate that SRP9 conveys its effects through endoplasmic reticulum (ER)-dependent synthesis and trafficking of membrane proteins, such as glutamate receptors. Discovery of this new FS gene and mechanism may provide new leads for early diagnosis and treatment of children with complex FS at risk for mTLE

Orbital bleeding in rats while under diethylether anaesthesia does not influence telemetrically determined heart rate, body temperature, locomotor and eating activity when compared with anaesthesia alone

The question addressed was whether orbital bleeding in rats, while under diethylether anaesthesia, affects their locomotor activity, body core temperature, heart rate rhythm and eating pattern. Roman High Avoidance (RHA) and Roman Low Avoidance (RLA) rats were used to enhance generalization of the results. Orbital bleeding when the rats were under diethylether anaesthesia was compared with diethylether anaesthesia alone. To take into account any effects of handling, the rats were also subjected to sham anaesthesia. The RHA rats urinated more during anaesthesia, needed more time to recover from the anaesthesia and showed a greater endocrine stress response to diethylether anaesthesia when compared with the RLA rats. During anaesthesia, the RHA rats showed a greater fall of body temperature and bradycardia than did the RLA rats. Diethylether anaesthesia reduced locomotor activity in the RHA rats, but had no effect in the RLA rats. In neither RHA nor RLA rats did anaesthesia plus orbital puncture, versus anaesthesia alone, influence body temperature, heart rate rhythm, locomotor and eating activity. The lack of effect of orbital puncture occurred both in the short term (within 2h) and long term (within 48 hours) and thus this study indicates that orbital puncture had, at least with respect to variables measured in the present study, no effect superimposed on that of diethylether anaesthesia.

An individual based, multidimensional approach to identify emotional reactivity profiles in inbred mice

Background Despite extensive environmental standardization and the use of genetically and microbiologically defined mice of similar age and sex, individuals of the same mouse inbred strain commonly differ in quantitative traits. This is a major issue as it affects the quality of experimental results. Standard analysis practices summarize numerical data by means and associated measures of dispersion, while individual values are ignored. Perhaps taking individual values into account in statistical analysis may improve the quality of results. New method The present study re-inspected existing data on emotional reactivity profiles in 125 BALB/cJ and 129 mice, which displayed contrasting patterns of habituation and sensitization when repeatedly exposed to a novel environment (modified Hole Board). Behaviors were re-analyzed on an individual level, using a multivariate approach, in order to explore whether this yielded new information regarding subtypes of response, and their expression between and within strains. Results Clustering individual mice across multiple behavioral dimensions identified two response profiles: a habituation and a sensitization cluster. Comparison with existing method(s) These retrospect analyses identified habituation and sensitization profiles that were similar to those observed in the original data but also yielded new information such as a more pronounced sensitization response. Also, it allowed for the identification of individuals that deviated from the predominant response profile within a strain. Conclusions The present approach allows for the behavioral characterization of experimental animals on an individual level and as such provides a valuable contribution to existing approaches that take individual variation into account in statistical analysis

Comparison of 2 blood sampling methods in mice to increase animal welfare and the reliability of experimental results

There is a strong need to gain systematic knowledge about the potential impact of routine procedures on laboratory animals to ensure animal welfare and reliability of experimental results. Blood sampling is a frequently used procedure within laboratory animal research. Two of the most common anesthesia-free techniques to obtain blood in mice are the saphenous venipuncture and submandibular bleeding. It is common practice that these methods are applied repeatedly to 1 individual. The impact of both techniques, either performed singly or repeatedly, on the animal’s welfare is not fully known yet. We directly compared the effects of both sampling methods on physiological stress responses, behavior, tissue damage, and procedure duration in 2 frequently used mouse strains: C57BL/6 and BALB/c mice (n = 45/strain). The mice were randomly assigned to 3 treatment groups (saphenous venipuncture, submandibular bleeding, control) of 15 mice/strain and were sampled weekly (80 μl/ blood sample) during 4 wk for the experimental groups and 5 wk for the control group. To evaluate the acute physiological stress response, plasma corticosterone levels were determined. As an indicator of chronic stress, body weights were recorded once a week and the thymus was weighed after necropsy. Behavior was recorded using video cameras in front of the cages and afterwards analyzed by a well-trained observer using event logging software. Tissue damage was evaluated by scoring pre-and postmortem hemorrhages and hematomas at the injection site and by measuring alanine transaminase, aspartate aminotransferase, and creatine kinase plasma levels. Submandibular bleeding appeared to be less time consuming (P<0.05) while providing higher sample volumes. However, this method led to increased acute stress responses in C57BL/6 mice (P = 0.03). All animals of both strains undergoing this procedure expressed more pain-related behavior (P < 0.05) and the extent of tissue damage at the injection site was significantly higher when compared to the saphenous venipuncture (P < 0.05). Thus, in order to avoid the undesirable effects of stress on experimental outcomes and to reduce the extent of tissue damage, saphenous venipuncture should be preferred above submandibular bleeding whenever possible

Comparison of 2 blood sampling methods in mice to increase animal welfare and the reliability of experimental results

There is a strong need to gain systematic knowledge about the potential impact of routine procedures on laboratory animals to ensure animal welfare and reliability of experimental results. Blood sampling is a frequently used procedure within laboratory animal research. Two of the most common anesthesia-free techniques to obtain blood in mice are the saphenous venipuncture and submandibular bleeding. It is common practice that these methods are applied repeatedly to 1 individual. The impact of both techniques, either performed singly or repeatedly, on the animal’s welfare is not fully known yet. We directly compared the effects of both sampling methods on physiological stress responses, behavior, tissue damage, and procedure duration in 2 frequently used mouse strains: C57BL/6 and BALB/c mice (n = 45/strain). The mice were randomly assigned to 3 treatment groups (saphenous venipuncture, submandibular bleeding, control) of 15 mice/strain and were sampled weekly (80 μl/ blood sample) during 4 wk for the experimental groups and 5 wk for the control group. To evaluate the acute physiological stress response, plasma corticosterone levels were determined. As an indicator of chronic stress, body weights were recorded once a week and the thymus was weighed after necropsy. Behavior was recorded using video cameras in front of the cages and afterwards analyzed by a well-trained observer using event logging software. Tissue damage was evaluated by scoring pre-and postmortem hemorrhages and hematomas at the injection site and by measuring alanine transaminase, aspartate aminotransferase, and creatine kinase plasma levels. Submandibular bleeding appeared to be less time consuming (P<0.05) while providing higher sample volumes. However, this method led to increased acute stress responses in C57BL/6 mice (P = 0.03). All animals of both strains undergoing this procedure expressed more pain-related behavior (P < 0.05) and the extent of tissue damage at the injection site was significantly higher when compared to the saphenous venipuncture (P < 0.05). Thus, in order to avoid the undesirable effects of stress on experimental outcomes and to reduce the extent of tissue damage, saphenous venipuncture should be preferred above submandibular bleeding whenever possible