The pathological effects of subcutaneous injections of asbestos fibres in mice: Migration of fibres to submesothelial tissues and induction of mesotheliomata

Abstract

Groups of 20 female

Beyond foreign‐body‐induced carcinogenesis: Impact of reactive oxygen species derived from inflammatory cells in tumorigenic conversion and tumor progression

“…21,25 When asbestos is experimentally injected into a subcutaneous space in mice, extensive inflammatory reaction develops; surprisingly the subcutaneously injected asbestos fibers are transported into submesothelium of thorax and abdomen. 26 The conspicuous feature of asbestos-associated mesotheliomas is persistent inflammation 27 and active fibrosis 28 evoked by asbestos fibers since immune system cannot remove the nondigestible particles that lead to chronic inflammation (also termed ''sterile inflammation''). 29,30 It is considered that possible causes of asbestosinduced mutation are ROS, reactive nitrogen species (RNS) and their by-products.…”

Milky spots (taches laiteuses) as structures which trap asbestos in mesothelial layers and their significance in the pathogenesis of mesothelial neoplasia

“…Hyperplastic changes were observed in milky spots after both subcutaneous and intravenous administration of asbestos in mice. The possible involvement of milky spots in the genesis of tumours of the mesothelium following exposure of animals to asbestos is discussed.There have been sevzral reports of the successful induction of mesothelioma in laboratory animals by intrapleural or intraperitoneal injection of asbestos, either alone or together with other agents (Smith et al, 1965;Roe et al, 1967; Wagner and Berry, 1969;Stanton and Wrench, 1972). In all these studies, the amounts of asbestos introduced into serosal cavities far exceed the amounts which could conceivably reach the serosal cavities of humans exposed to asbestos by inhalation or ingestion.…”

Non-carcinogenicity of cadmium-free ferritin

“…Asbestos bodies consist of asbestos fibres coated with material which contains ferritin (Davies, 1965). The present results suggest that this deposit of ferritin is of little importance in relation to the induction of neoplasms by asbestos fibres (Wagner, 1962;Roe, Carter, Walters and Harington, 1967) Muir and Golberg (1961) have shown that after two introductions of iron dextran into the subcutaneous tissues, the iron moiety is stored either as ferritin or as haemsoderin. Despite this conversion, sarcomas frequently arise at the site of injection of iron-dextran in rats and in various other species (see Roe, 1967, for review).…”

“…The present results suggest that this deposit of ferritin is of little importance in relation to the induction of neoplasms by asbestos fibres (Wagner, 1962;Roe, Carter, Walters and Harington, 1967) Muir and Golberg (1961) have shown that after two introductions of iron dextran into the subcutaneous tissues, the iron moiety is stored either as ferritin or as haemsoderin. Despite this conversion, sarcomas frequently arise at the site of injection of iron-dextran in rats and in various other species (see Roe, 1967, for review). In the first of the present experiments, the total amount of iron injected in the form of ferritin (126 mg. per rat) was less than the total amount (300 mg.) of iron in the form of iron dextran required to induce injection-site sarcomas in 25 % of rats of the same strain (Roe, 1967).…”

“…Despite this conversion, sarcomas frequently arise at the site of injection of iron-dextran in rats and in various other species (see Roe, 1967, for review). In the first of the present experiments, the total amount of iron injected in the form of ferritin (126 mg. per rat) was less than the total amount (300 mg.) of iron in the form of iron dextran required to induce injection-site sarcomas in 25 % of rats of the same strain (Roe, 1967). The non-carcinogenicity of ferritin in amounts likely to be formed after the injection of relatively large doses of iron dextran has, therefore, yet to be established.…”