Comparison of intrinsic exercise capacity and response to acute exercise in ICR (Institute of Cancer Research) mice derived from three different lineages / 한국실험동물학회지

Background@#As a laboratory animal resource, the ICR mouse is commonly used in a variety of research fields. However, information on differences in exercise-related characteristics in ICR mice derived from different lineages and the underlying mechanisms remains to be elucidated. In this study, we investigated the intrinsic exercise capacity and a magnitude of response to acute exercise, and sought to identify mechanisms contributing to difference in Korl:ICR (a novel ICR lineage recently established by the National Institute of Food and Drug Safety Evaluation, Korea) and two commercialized ICR lineages derived from different origins (viz., A:ICR mouse from Orient Bio Com, the United States, and B:ICR mouse from Japan SLC Inc., Japan). @*Results@#Results showed that despite no significant difference in body weight and weight-proportioned tissue mass of heart and skeletal muscles among groups, the relatively low intrinsic exercise capacity and exaggerated response to acute exercise were identified in B:ICR comparted with Korl:ICR and A:ICR, as reflected by total work and lactate threshold (LT). Also, the mitochondrial efficiency expressed as the complex 1 and complex 1 + 2 respiratory control ratio (RCR) values for cardiac mitochondrial O 2 consumption in B:ICR was significantly lower than that in Korl:ICR with higher level of state 2 respiration by glutamate/malate and UCP3 expression in cardiac muscle. @*Conclusions@#Taken together, these results indicate that the intrinsic exercise capacity of ICR mouse varies according to lineages, suggesting the role of cardiac mitochondrial coupling efficiency as a possible mechanism that might contribute to differences in the intrinsic exercise capacity and magnitude of response to exercise.

Comparison of intrinsic exercise capacity and response to acute exercise in ICR (Institute of Cancer Research) mice derived from three different lineages / 한국실험동물학회지

Background@#As a laboratory animal resource, the ICR mouse is commonly used in a variety of research fields. However, information on differences in exercise-related characteristics in ICR mice derived from different lineages and the underlying mechanisms remains to be elucidated. In this study, we investigated the intrinsic exercise capacity and a magnitude of response to acute exercise, and sought to identify mechanisms contributing to difference in Korl:ICR (a novel ICR lineage recently established by the National Institute of Food and Drug Safety Evaluation, Korea) and two commercialized ICR lineages derived from different origins (viz., A:ICR mouse from Orient Bio Com, the United States, and B:ICR mouse from Japan SLC Inc., Japan). @*Results@#Results showed that despite no significant difference in body weight and weight-proportioned tissue mass of heart and skeletal muscles among groups, the relatively low intrinsic exercise capacity and exaggerated response to acute exercise were identified in B:ICR comparted with Korl:ICR and A:ICR, as reflected by total work and lactate threshold (LT). Also, the mitochondrial efficiency expressed as the complex 1 and complex 1 + 2 respiratory control ratio (RCR) values for cardiac mitochondrial O 2 consumption in B:ICR was significantly lower than that in Korl:ICR with higher level of state 2 respiration by glutamate/malate and UCP3 expression in cardiac muscle. @*Conclusions@#Taken together, these results indicate that the intrinsic exercise capacity of ICR mouse varies according to lineages, suggesting the role of cardiac mitochondrial coupling efficiency as a possible mechanism that might contribute to differences in the intrinsic exercise capacity and magnitude of response to exercise.

Comparative analysis of restraint stress-induced depressive-like phenotypes in C57BL/6N mice derived from three different sources / 한국실험동물학회지

C57BL/6NKorl mice are a novel mouse stock recently developed by the National Institute of Food and Drug Safety Evaluation in Korea. Extensive research into the nature of C57BL/6NKorl mice is being conducted. However, there is no scientific evidence for the phenotypic response to restraint stress (RST), a stress paradigm for modeling depressive disorders, in rodents. In this study, we investigated the repeated RST-induced depressive-like phenotypes in C57BL/6 N mouse substrains (viz., C57BL/6NKorl mice from Korea, C57BL/6NA mice from the United States, and C57BL/6NB mice from Japan) obtained from different sources. The results showed that C57BL/6 N mice derived from various sources exposed to repeated RST resulted in depressive-like phenotypes reflected by a similar degree of behavioral modification and susceptibility to oxidative stress in a duration-dependent manner, except for the distinctive features (increased body weight (BW) and tolerance to the suppression of BW gain by exposure to repeated RST) in C57BL/6NKorl mice. Taken together, the duration-dependent alteration in depressive-like phenotypes by repeated exposure to RST observed in this study may provide valuable insights into the nature of C57BL/6NKorl mice as an alternative animal resource for better understanding of the etiology of depressive disorders and the mechanisms of antidepressant actions.

Comparative analysis of dose-dependent neurotoxic response to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in C57BL/6 N mice derived from three different sources / 한국실험동물학회지

MPTP, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine is commonly used to induce nigrostriatal defects to induce parkinsonism and/or parkinsonian syndrome, to replicate the lesions seen in Parkinson's disease (PD), with use in numerous PD models in mice. It has been suggested that various biological characteristics including strain could result in differing mortality rates, sensitivity to MPTP administration, and reproducibility of lesions in mice, but there is no evidence on the sensitivity of C57BL/6 mice from different origins to MPTP and its associated pathological lesions. In this study, we investigated the magnitude of the dose-dependent response to acute MPTP administration in C57BL/6NKorl mice and two commercialized C57BL/6 stocks derived from the United States and Japan. We measured biological features (body weight, temperature, and composition), nigrostriatal neurotoxic responses (dopamine levels, tyrosine hydroxylase enzymes, and protein carbonylation) and motor function. In results, the three different C57BL/6 stocks exhibited similar overall neurotoxic response and locomotor impairment which increased in a dose-dependent manner with acute MPTP administration (10 mg/kg, 20 mg/kg, and 30 mg/kg, all with external heat support), although some of these differences were not significant. In conclusion, this study provides scientific evidence that C57BL/6NKorl mice can be used as an alternative animal model for practical and targeted PD research.