The combined effects of microgravity and ionizing radiation on the body of rats in a ground-based study

  • M. A. Lebedeva Institute of General Pathology and Pathophysiology, Moscow, Russian Federation; Research Institute of Space Medicine of All-Russian Center for Disaster Medicine “Protection” of the Federal Biomedical Agency of Russia, Moscow, Russian Federation http://orcid.org/0000-0002-4601-8762
  • Yu. S. Medvedeva Institute of General Pathology and Pathophysiology, Moscow, Russian Federation http://orcid.org/0000-0003-0414-8427
  • M. V. Baranov Research Institute of Space Medicine of All-Russian Center for Disaster Medicine “Protection” of the Federal Biomedical Agency of Russia, Moscow, Russian Federation http://orcid.org/0000-0002-6300-6392
  • I. B. Alchinova Institute of General Pathology and Pathophysiology, Moscow, Russian Federation; Research Institute of Space Medicine of All-Russian Center for Disaster Medicine “Protection” of the Federal Biomedical Agency of Russia, Moscow, Russian Federation http://orcid.org/0000-0001-5294-7317
  • M. S. Demorzhi Institute of General Pathology and Pathophysiology, Moscow, Russian Federation http://orcid.org/0000-0001-7190-4304
  • N. N. Zolotov Zakusov Institute of Pharmacology, Moscow, Russian Federation http://orcid.org/0000-0003-3528-4659
  • A. V. Arutyunyan Konstantinov Petersburg Institute of Nuclear Physics, Gatchina of the Leningrad Region, Russian Federation
  • M. Yu. Karganov Institute of General Pathology and Pathophysiology, Moscow, Russian Federation; Research Institute of Space Medicine of All-Russian Center for Disaster Medicine “Protection” of the Federal Biomedical Agency of Russia, Moscow, Russian Federation http://orcid.org/0000-0002-5862-8090
DOI: https://doi.org/10.25557/2310-0435.2022.01.29-41
Keywords: space flight factors, long-term effects, combined effects, ECG, laser correlation spectroscopy

Abstract

During a space flight (SF), microgravity and radiation affect living objects simultaneously; however, most ground-based studies have focused on isolated effects of SF factors on physiological parameters. There is still no unified theory about the combined effect of radiation and microgravity on the human body. In this regard, combined effects of SF factors are of great interest.

Aim: To study long-term effects of two combinations of simulated microgravity and ionizing radiation (IR) on rat organs.

Methods: Two-week hindlimb unloading (HU); single acute gamma-irradiation at a dose of 1.5 Gy; ECG; laser correlation spectroscopy; measurement of blood corticosterone concentration; measurement of body and myocardial weight; morphological study of myocardial tissue. The effect of an exposure to the HU + irradiation combination was studied for 1.5 months and of an exposure to the Irradiation + HU combination for 3 months.

Results: The body weight was decreased in groups of combined exposures. The smallest changes in the myocardial electrical conduction were observed in the HU group. The Irradiation + HU group showed an increase in the QTc interval duration whereas the HU + Irradiation group had a prolonged PQ interval and a decreased amplitude of P and R waves. Laser correlation spectroscopy in the combined exposures revealed an increase in the percentage of particles with a small hydrodynamic radius. An increase in blood concentration of corticosterone was found in the radiation-exposed groups. The morphological picture of the myocardium of experimental groups showed diffuse focal changes. In the groups exposed to a combination of two SF factors, pronounced diffuse fibrosis with characteristic features of collagen deposition was observed.

Conclusion: The combined effect of simulated microgravity and IR caused more pronounced weight loss and morphological changes in the myocardium. Disorders of the myocardial electrical conduction and the increased corticosterone concentration in the combined exposure groups were both associated to a greater degree with the action of IR. The imbalance of blood serum homeostasis was most likely due to the influence of HU. Future insight into this issue will improve our understanding of effects of the space environment on human health and will help reduce the risks associated with long-term space missions.

Published
2022-04-27
How to Cite
Lebedeva, M. A., Medvedeva, Y. S., Baranov, M. V., Alchinova, I. B., Demorzhi, M. S., Zolotov, N. N., Arutyunyan, A. V., & Karganov, M. Y. (2022). The combined effects of microgravity and ionizing radiation on the body of rats in a ground-based study. Patogenez (Pathogenesis), 20(1), 29-41. https://doi.org/10.25557/2310-0435.2022.01.29-41
Issue
Vol. 20 No. 1 (2022): Патогенез
Section
Experimental researches