Orally ingested chrysotile asbestos affects rat lungs and pleura

Our plain-English summary of Orally ingested chrysotile asbestos affects rat lungs and pleura, by H.C. Hasanoglu, E. Bayram, A. Hasanoglu, et al (Archives of Environmental & Occupational Health, 2008).

The study

• Authors: H.C. Hasanoglu, E. Bayram, A. Hasanoglu, F. Demirag
• Journal: Archives of Environmental & Occupational Health
• Published: 2008;63(2):71-5
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The authors designed this study to show the effects of orally ingested asbestos on the lungs and pleura. They designated 3 groups of rats: group A (n = 18) was given 1.5 g/L asbestos in water, group B (n = 18) was given 3 g/L asbestos in water, and group C (n = 15), as a control group, was given only water. Histopathological evaluation of lungs and pleura of the rats after 6 months revealed significant mesothelial proliferation and asbestos bodies. After 9 months, more rats exhibited mesothelial proliferation in group B than in group A (p < .05). The number of rats with asbestos bodies in their lungs was greater in group B than in group A. More rats in group B than in group A had asbestos in their spleen. The authors observed mesothelial proliferation in all group B rats at the end of 12 months. Ingested asbestos traveled from the gastrointestinal system to the lungs, likely via a lymphohematological route, leading to mesothelial proliferation, which may lead to malignancies.

In plain English

This was an animal experiment in Turkey. The authors studied 51 young Wistar rats. Eighteen drank water containing 1.5 g/L of chrysotile asbestos from a mine in Sivas, central Anatolia. Another 18 drank water containing 3 g/L, and 15 control rats received plain water. At 6, 9 and 12 months, six rats from each asbestos group and five controls were killed. Their lungs, pleura, liver, spleen and mesenteric lymph nodes were examined under a microscope. No rat became ill, and none had visible masses. Mesothelial proliferation (extra layers of cells on the lining surface) was seen in 3 of 6 rats in each asbestos group at 6 months. At 12 months it was seen in all 6 higher-dose rats and 4 of 6 lower-dose rats. Asbestos bodies appeared in the lungs of some exposed rats from 9 months onward, and in the spleen at every time point. Control rats showed no changes. The authors concluded that ingested asbestos reached the lungs, likely through the lymph and blood, causing changes they said may lead to malignancies.

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 given asbestos in drinking water, compared with control rats given plain water)
• Who was studied: 51 Wistar rats aged 10 to 12 weeks, studied in the animal laboratory of Ankara Educational and Research Hospital, Turkey. There were 18 rats in group A, 18 in group B and 15 controls (group C). At 6, 9 and 12 months, 6 rats from each of groups A and B and 5 controls were killed and examined.
• Exposure: Chrysotile (white asbestos) from a mine in the Kangal Kamper district of Sivas, purified and suspended in drinking water. Group A received 1.5 g/L, group B received 3 g/L, and group C (controls) received water only. The authors note rats drink 15 to 20 mL of water per day.
• Main results:
  • At 6 months, congestion, bronchiolitis and mesothelial proliferation in the lungs and pleura were more common in both asbestos groups than in controls. Per Table 1, mesothelial proliferation was seen in 3 of 6 group A rats, 3 of 6 group B rats and 0 of 5 controls.
  • At 9 months, the authors reported significantly more rats with mesothelial proliferation in group B (3 g/L; 4 of 6 per Table 1) than in group A (1.5 g/L; 2 of 6). Asbestos bodies were seen in the lungs of 3 of 6 group B rats and 2 of 6 group A rats.
  • At 12 months, all 6 group B rats had mesothelial proliferation, and 5 of them had asbestos bodies in their lungs. Per Table 1, in group A 4 of 6 had mesothelial proliferation and 2 of 6 had asbestos bodies in the lungs.
  • Interstitial fibrosis was seen only in group B in Table 1: 1 of 6 rats at 6 months and 3 of 6 at 9 months. The authors reported the 9-month finding as significant.
  • Asbestos bodies were found in the spleen of exposed rats at every time point. Per Table 1, this was 4 and 5 of 6 rats at 6 months, 3 and 4 of 6 at 9 months, and 6 and 5 of 6 at 12 months (groups A and B respectively). These were generally accompanied by subcapsular fibrosis of the spleen.
  • No control rat showed any pathological change in the lung or spleen at any time. The liver and mesenteric lymph nodes were normal.
  • No rat became ill or died of natural causes. None had visible masses, ascites or lymphadenopathy.
• The authors' conclusion: The authors concluded that they found definite tissue changes, such as fibrosis and mesothelial proliferation, in the lungs of rats that swallowed rather than inhaled asbestos. They believed this showed asbestos traveling through the body via the lymph and blood, which they said may lead to malignancies.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Chrysotile.

Medical terms in this study, explained in our Lexicon: Chrysotile, Pleura, Asbestos Bodies.

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