Free radical oxidation in rats in the delayed period after combined exposure to dust and radiation

Our plain-English summary of Free radical oxidation in rats in the delayed period after combined exposure to dust and radiation, by S.O. Tapbergenov, B.A. Zhetpisbaev, O.Z. Ilderbayev, et al (Bulletin of Experimental Biology and Medicine, 2013).

The study

• Authors: S.O. Tapbergenov, B.A. Zhetpisbaev, O.Z. Ilderbayev, H.S. Zhetpisbaeva, R.R. Olzhayeva, I.I. Prozor, O.A. Usenova, G.O. Ilderbayeva
• Journal: Bulletin of Experimental Biology and Medicine
• Published: 2013;154(6):747-9
• Cited by: 2 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

We studied the intensity of free radical processes in organs (liver, spleen, thymus, lymph nodes of the small intestine, and adrenal glands) and cells (lymphocytes) in the delayed period after combined exposure to a sublethal dose of γ-radiation (6 Gy) and asbestos dust particles. Combined exposure was followed by accumulation of LPO metabolites (diene conjugates and malonic dialdehyde) in homogenates of the studied organs and resulted in antioxidant defense failure in experimental animals. Ionizing radiation have a pivotal role in these processes.

In plain English

In this experiment, the authors divided 45 male white rats into three groups of 15. The control rats were given saline. The second group had asbestos dust placed directly into the lungs through the windpipe. The third group got the same dust plus a single whole-body dose of 6 Gy of gamma radiation. The asbestos type was not stated, and no group received radiation alone. Ninety days after irradiation, the authors measured two markers of lipid peroxidation (oxidative damage to fats in cells), conjugated dienes and malonic dialdehyde. They measured these in the liver, spleen, thymus, small-intestine lymph nodes, adrenal glands and blood lymphocytes. In asbestos-only rats, the markers rose in several tissues but fell in some, such as conjugated dienes in the adrenal glands and malonic dialdehyde in the spleen. In rats given both exposures, both markers were higher than in controls in all six tissues, and in most tissues higher than in asbestos-only rats. The authors concluded that asbestos dust activated lipid peroxidation, that the combined effects were more pronounced, and that radiation was the dominating agent.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Animal experiment: rats randomly assigned to a control group, an asbestos dust group, or an asbestos dust plus radiation group. Differences were tested with Student's t test.
• Who was studied: 45 outbred white male rats weighing 200 to 240 g, 15 per group, killed 90 days after radiation exposure (the 'delayed period'). The study was done at the State Medical University, Semey, Kazakhstan.
• Exposure: Asbestos dust (fiber type not stated), ground to sizes the authors describe as similar to workplace airborne dust, was introduced into the lungs through the trachea. The authors report that asbestosis was confirmed histologically in lung tissue. Group 3 also received a single whole-body dose of 6 Gy of cobalt-60 gamma rays. Controls received physiological saline.
• Main results:
  • Asbestos-only rats compared with controls, conjugated dienes: increased 1.27 times in blood lymphocytes, 1.36 times in thymus, 2.43 times in liver, 1.51 times in spleen and 2.8 times in small-intestine lymph nodes. They decreased 1.72 times in the adrenal glands (all p less than 0.05).
  • Asbestos-only rats compared with controls, malonic dialdehyde: increased 2.2 times in lymph nodes, 4.67 times in thymus and 2.67 times in adrenal glands, and decreased 1.78 times in the spleen (p less than 0.05). It did not change in the liver or blood lymphocytes.
  • Asbestos plus radiation rats compared with controls, conjugated dienes: higher in all six tissues (p less than 0.05). Table values, control versus combined: liver 0.69 vs 1.88; spleen 1.28 vs 2.24; lymph nodes 0.35 vs 0.96; thymus 0.49 vs 1.10; adrenal glands 1.19 vs 1.58; blood lymphocytes 0.29 vs 0.48 (relative units).
  • Asbestos plus radiation rats compared with asbestos-only rats, conjugated dienes: higher in lymphocytes (1.3 times), thymus (1.64), liver (1.12) and adrenal glands (2.29) (p less than 0.05). There was no significant change in spleen or lymph nodes.
  • Asbestos plus radiation rats compared with controls, malonic dialdehyde: higher in lymphocytes (2.29 times), liver (1.79), spleen (1.22), lymph nodes (2.8), adrenal glands (3.67) and thymus (5) (p less than 0.05).
  • Asbestos plus radiation rats compared with asbestos-only rats, malonic dialdehyde: higher in lymphocytes (1.78 times), liver (1.56), spleen (2.17), lymph nodes (1.27) and adrenal glands (1.38) (p less than 0.05). The table marks the thymus difference as not significant.
• The authors' conclusion: The authors concluded that asbestos dust activates lipid peroxidation in immune organs and cells. They found the effects of combined radiation and asbestos dust in the delayed period more pronounced, amounting to a 'lipid peroxidation syndrome', and judged ionizing radiation to be the dominating agent.

Related studies

• An ESR and HPLC-EC assay for the detection of alkyl radicals — C.P. Novakov, D. Feierman, et al. (2001)
• Quantifying health effects from the combined action of low-level radiation and other environmental agents: can new approaches solve the enigma? — W. Burkart, G.L. Finch, et al. (1997)
• Cytokine and free radical responses of alveolar macrophages in vitro to asbestos fibres — L.C. Mongan, T. Jones, et al. (2000)
• Free radical activity of synthetic vitreous fibers: iron chelation inhibits hydroxyl radical generation by refractory ceramic fiber — D.M. Brown, C. Fisher, et al. (1998)
• Tobacco smoke: involvement of reactive oxygen species and stable free radicals in mechanisms of oxidative damage, carcinogenesis and synergistic effects with other respirable particles — A. Valavanidis, T. Vlachogianni, et al. (2009)
• Free radical activity associated with the surface of particles: a unifying factor in determining biological activity? — K. Donaldson, P.H. Beswick, et al. (1996)

Browse return to medical research.