PhD, Associate Professor A.N. Zakharova¹
PhD Yu.G. Kalinnikova¹
Postgraduate E.S. Negodenko¹
Postgraduate A.A. Orlova¹
Dr. Med., Professor L.V. Kapilevich^{1, 2
1}National Research Tomsk State University, Tomsk
²Siberian State Medical University, Tomsk

Keywords: cyclic physical training model, treadmill, small laboratory animals.

Background. Lately in sports physiology a growing priority has been given to experimental research [5, 8, 9] of physical training process that is known to trigger molecular changes in muscles and stimulate endocrine function [6, 7]. It has become traditional to use laboratory mice in the experiments to clarify the physical training process [2, 3], since mice have many advantages to other small laboratory animals – e.g. in homology of the human and murine genes that is very close in many aspects. The mice-using experiments may model quite a few physiological and pathological changes in the human body that are well traceable due to the short reproductive cycles [4]. Physical training experiments may use a wide range of physical loads including wheel running, swimming, hanging, weight trainings etc. Of special interest for such experiments are the treadmill trainings [4].

Objective of the study was to develop and test benefits of a cyclic physical training model on laboratory mice.

Methods and structure of the study. We sampled for the new cyclic physical training model testing experiment the 12 weeks-old male mice of C57BL/6 line (n = 60 procured from the Institute of Pharmacology’s Siberian Affiliate) split up into Experimental and Reference Groups (EG, RG) of 30 mice each). The RG was untrained, and the EG training was designed under the new model. The mice were kept in an isolated ventilated vivarium at 24±1.0°C, air humidity of 60%, and day/night regime of 12+12. Every mouse was marked and kept in quarantine for 7 days, 6 mice per cage, with free access to water and standard food "Prokorm" (made by ZAO "Biopro", Novosibirsk).

We used a treadmill for small laboratory animals made on a special contract for the cyclic physical trainings. The treadmill includes the following elements: (1) Rough-surface varied-incline rubber run belt of 60 cm²; (2) Casing to divide the run surface into 10 isolated tracks; (3) Electrical stimulation module with the contact copper plates behind the run spots to force the mice run; and (4) Control unit (see Figure 1).

Body mass of the animals was tested on a permanent basis by DL-WP laboratory balance (A&DI, Japan) and processed by STATISTICA10.0 software toolkit, with the group differences rated by the nonparametric Mann-Whitney test, and with the differences deemed statistically significant at p<0.05; and the data presented in Xav ± SE format. The experiment was approved by the local Ethics Committee of the Biological Institute of National Research Tomsk State University (Protocol No. 32 dated December 2, 2019).

Results and discussion. The cyclic physical training model was tested for 4 weeks, with every weekly microcycle including 6 run days and 1 rest day: see the cyclic physical training model design in Table 1 hereunder. The mice run on the treadmill at varied speeds, with the runs alternated with passive rest breaks to simulate as close as possible the natural lifestyles of the animals (as reported by etiology of rodents, their natural lifestyle is dominated by short dashes with passive rest breaks, with the top speeds relatively seldom [1].

The 4-week cyclic physical training model testing experiment resulted in the EG body mass reduction versus the RG due to the high-intensity aerobic practices – as verified by the pre- versus post-experimental weights averaging 28.67±0.6g and 27.98±1.12g, respectively, (p <0.05), versus the RG body mass growth up to 31.02±1.3g (p <0.05): Figure 2.

It should be noted that every animal stood the experiment well. Actually it took only one day for the mice to get used to the cyclic physical training and run effectively, with no abnormal behavioral and functional reactions fixed; no reductions in the water/ food demands; and not one lethal case in the experiment.

Conclusion. The new cyclic physical training model was tested beneficial for small laboratory animals and may be recommended for a wide range of preclinical and other experimental studies in sports physiology.

The study was sponsored by a grand finance from the RRF under Research Project # 19-15-00118

Figure 1. Treadmill for small laboratory animals: A general view; B run belt and electric stimulators

Figure 2. Body mass variation for the test period; *p<0.05 for intergroup difference

Table 1. Cyclic physical training model design

References

1. Belyaeva G.S., Pekin A.V., Danilov N.A., Erofeev A.I. Experimental model for physical performance rating in small laboratory animals when building positive motivation. Prikladnye problemy bezopasnosti tekhnicheskikh i biotehnicheskikh sistem. 2015. No. 1. pp. 29-32.
2. Kapilevich L.V., Kabachkova A.V., Zakharova A.N. et al. Skeletal muscle secretory function: mechanisms of production and physiological effects of myokines. Uspekhi fiziol. nauk. 2016. v. 47. No. 2. pp. 7-26.
3. Kapilevich L.V., Milovanova K.G., Sidorenko S.V. et al. Effect of dynamic and static loads on sodium and potassium levels in skeletal muscles in mice. Byulleten eksperimentalnoy biologii i meditsiny. 2020. v. 169. no. 1. pp. 4-7.
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6. Kapilevich L.V., Kironenko T.A., Zaharova A.N., Kotelevtsev Y.V., Dulin N.O., Orlov S.N. Skeletal muscle as an endocrine organ: Role of [Na+]i/[K+]i-mediated excitation transcription сoupling. Genes & Diseases. 2015. V. 2, no.4. pp. 328–336.
7. Kapilevich L.V., Zakharova A.N., Kabachkova A.V., Kironenko T.A., Orlov S.N. Dynamic and static exercises differentially affect plasma cytokine content in elite endurance- and strength-trained athletes and untrained volunteers. Frontiers Physiology. 2017. V. 8. No. 35.
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9. Zhang H.J., He J., Pan L.L., Ma Z.M., Han C.K., Chen C.S. Effects of moderate and vigorous exercise on nonalcoholic fatty liver disease: a randomized clinical trial. JAMA Intern Med. 2016. No. 176. pp. 1074–1082.

Corresponding author: zvi@tut.by

Abstract

Objective of the study was to develop and test benefits of a cyclic physical training model on laboratory mice.

Methods and structure of the study. We sampled for the new cyclic physical training model testing experiment the 12 weeks-old male mice of C57BL/6 line (n = 60 procured from the Institute of Pharmacology’s Siberian Affiliate) split up into Experimental and Reference Groups (EG, RG) of 30 mice each). The RG was untrained, and the EG training was designed under the new model.

Results and conclusions. All mice performed the physical loads successfully. After the first insight into the test procedure, the animals completely familiarized themselves with the task, and on the second day performed the loads in full. There was no abnormal reaction in their behavior and functional state. No reduction of food or water intake was detected. No fatalities were reported during or after the tests either.

The new cyclic physical training model was tested beneficial for small laboratory animals and may be recommended for a wide range of preclinical and other experimental studies in sports physiology.