The effect of intermittent vibration on the morpho-functional state of the nervous system in rats

Introduction. Prolonged intense vibration exposure is a chronic stress factor for animals and humans, which causes disorders at both the neurohumoral and molecular cellular levels. During experimental studies on animals, the authors found that prolonged vibration has a negative effect on the neurons of the cerebral cortex and, as a result, on the state of bioelectric activity of the brain and behavioral reactions of rats. However, little is known about the relationship of pain sensitivity indices with morphological changes in the structure of rat nervous tissue in the dynamics of intermittent vibration exposure.

The study aims to investigate the effect of intermittent vibration exposure on the morphofunctional state of the nervous system in Wistar rats.

Materials and methods. The experiments were performed on male Wistar rats (n=59) weighing 160–240 g. The researchers divided the rats into 2 groups: control and experimental. An experimental group of rats was exposed to vibration at a fundamental frequency of 16 Hz, with a vibration acceleration of 120 dB. The authors performed vibration exposure in an intermittent mode, consisting of alternating eight 20-minute vibration periods and eight 10-minute breaks of 4 hours a day 5 times a week for a total duration of the experiment of 9 weeks. Scientists assessed the change in pain response thresholds in rats in the dynamics of vibration effects using classical pain models — "Hot plate" and "Tail Flick". Structural changes developing as a result of prolonged vibration exposure were determined based on the results of morphological examination of rat brain tissue.

Results. Intermittent vibration exposure to rats for 9 weeks led to a change in the threshold of pain response — to an extension of the latent response period: in the Hot plate test from weeks 3 to 6 by 41% and 46%, respectively, compared with the control group; in the Tail flick test — by 3 by 32% at week 6, by 28% at week 6, and by 65% at week 9 compared to the control group. Experts have identified the dynamics of morphological disorders in the brain tissue of rats exposed to intermittent vibration. On the 3^rd week of exposure to vibration, disturbances in the structure of brain tissue begin to manifest themselves only in the form of an uneven distribution of nerve cells and the appearance of hyperchromic neurons. At the 6^th and 9^th weeks of vibration application, the authors observed more pronounced hyperchromia of the nuclei of neurons, partial cell decay in some areas of the brain with zonal loss of the latter and the phenomena of neuronophagy, which indicates degenerative changes in the central nervous system.

Limitations. The experiments were conducted on laboratory rats of the same line and the same sex, using intermittent vibration exposure at a single frequency of 16 Hz, with a vibration acceleration of 120 Db.

Conclusion. Intermittent vibration exposure during 3, 6, and 9 weeks led to an increase in pain response thresholds in rats in both the Hot plate and Tail flick tests, which is associated with a general decrease in CNS activity. A comparison of the results of histological studies obtained at weeks 3, 6, and 9 of intermittent vibration exposure showed progressive morphological and structural changes in the rat brain.

Ethics. The study was approved by the local Ethics Committee of the Research Institute for Complex Problems of Hygiene and Occupational Diseases (Minutes of meeting No. 4 § 2 dated 11/18/2021). The animals were kept, fed and removed from the experiment in accordance with the requirements of the European Convention for the Protection of Vertebrates Used for Experimental or Other Scientific Purposes (ETS No. 123, European Convention for the Protection of Vertebrate Animals used for Experimental and other Scientific Purposes, Strasbourg, 18.03.1986).

Contributions:
Zhukova A.G. — research concept and design, material collection and data processing, text writing;
Gorokhova L.G. — conducting an experiment, collecting material and processing data, editing text;
Gostyaeva E.P. — conducting an experiment, collecting material and processing data;
Koltunova A.A. — conducting an experiment, collecting material and processing data;
Kazitskaya A.S. — conducting an experiment, collecting material and processing data;
Bugaeva M.S. — material collection and data processing;
Bondarev O.I. — data processing, text editing.

Acknowledgement. We would like to express our gratitude to the students of the Faculty of Physical Culture, Natural Sciences and Environmental Management of the Kuzbass Humanitarian and Pedagogical Institute of Kemerovo State University, who study in Biology and Chemistry, for their help in setting up the experiment: Zhukova A.A., Kozlova V.N., Logvinsky V.A., Plotnikova A.O.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 02.06.2026 / Accepted: 09.06.2026 / Published: 11.08.2026

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