The short term effects of chronic asbestos ingestion in rats

The effects of ingestion of asbestos in laboratory rats were examined by feeding a diet supplemented with an asbestos/margarine formulation for periods up to 1 yr. UICC standard reference samples of chrysotile A, crocidolite and amosite were used throughout this study. Animals were examined for short-term clearance and evidence of penetration of, or damage to, the gut mucosa. There was no evidence of asbestos retention within the gut lumen, and no sign of cell penetration or damage to the intestinal mucosa in any of the animals under test. Results of scanning electron microscope investigations are presented, together with statistical analyses, to show that if penetration of the gastrointestinal tract did occur, it could only have done so to a minimal extent.