The advantages and limitations of an in vivo test system for investigating the cytotoxicity and fibrogenicity of fibrous dusts.

Sykes, S. E.; Morgan, A.; Moores, S. R.; Davison, Wilburt C.; Beck, J. D.; Holmes, Andrew

doi:10.1289/ehp.8351267

Cited by 12 publications

(7 citation statements)

References 12 publications

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“…For group II, the histopathological examination of the trachea and main bronchia has shown for cases 10,11,12,13, and 16 the presence of a nodular inflammatory infiltrate with lymphocytes, hystiocytes, rare macrophages, and neutrophils in the submucosa (62, 5%). In some histological sections, the lymphohystiocitary infiltrate extended from the subepithelial layer to the muscular layer of the trachea and main bronchia.…”

Section: Resultsmentioning

confidence: 99%

Lung response after subchronic glass fiber intratracheal instillation—an experimental study on rats

Domokos-Hancu

Man

Liana

et al. 2014

Experimental Lung Research

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The aim of the study was to identify the effects on the lung after subchronic glass fiber intratracheal instillation study on rats. We evaluated the toxicological effects on the lung: persistent inflammatory reaction, cell proliferation, and pulmonary fibrosis on histopathological examination. We performed a glass fiber intratracheal instillation study on total 32 Wistar rats. The animals were divided into four groups: three test groups exposed to different doses of glass fiber and one control group. One week after the end of the exposure period, all animals were euthanized. The histopathological examination of the lung performed in this study followed both distribution of the lesions through the multilevel biopsies that were taken and the inflammatory profile using both hematoxilin-eozin and Sirius red staining. The inflammatory lesions described for the first group were minimal/slight (grade I) and the total score was between 0 and 10 points (mean value = 3). For the second group, the inflammatory lesions were moderate/marked (grade II) with discrete collagen proliferation and discrete fibrosis and the total score ranged between 11 and 20 points (mean value = 11,250). For the third group, the described inflammatory lesions were massive with total score ranging between 21 and 30 points with collagen deposition, pulmonary and pleural fibrosis, and lung emphysema (mean value = 21,750) and no lesion in control group (with statistically significant difference P ≤ .001). This study of fiber glass intratracheal instillation of three different doses demonstrates that exposure to fiber glass is responsible for the development of persistent inflammatory response and a large range of hystopathological lesions which correlate to the administered dose.

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Section: Resultsmentioning

confidence: 99%

Lung response after subchronic glass fiber intratracheal instillation—an experimental study on rats

Domokos-Hancu

Man

Liana

et al. 2014

Experimental Lung Research

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“…Another methodological limitation in the earlier experiments was due to the low fiber number remaining after 1 and 2 years, necessitating very long and tedious examination of the SEM and TEM photographs of the filtered fibers. Parts of the earlier study (4) suggested to achieve optimum dust distribution with a limitation of the doses administered to a maximum of 0.6 mg/g fresh ie after intratracheal weight of lung (18).…”

Section: Resultsmentioning

confidence: 99%

Comparative investigations of the biodurability of mineral fibers in the rat lung.

Muhle

Bellmann

Pott

1994

Environ Health Perspect

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The biodurability of various glass fibers, rockwool, and ceramic fibers was examined in rat lungs and compared with natural mineral fibers. Experiments were based on studies that have shown that the biodurability of fibers is one of the essential factors of the carcinogenic potency of these materials. Sized fractions of fibers were instilled intratracheally into Wistar rats. The evenness of distribution of fibers in the lung was checked by scanning electron microscopy (SEM) or careful examination of the fiber suspension before treatment. After serial sacrifices up to 24 months after treatment, the fibers were analyzed by SEM following low temperature ashing of the lungs. Parameters measured included number of fibers, diameter, and length distribution at the various sacrifice dates, so that analyses could be made of the elimination kinetics of fibers from the lung in relation to fiber length (FL). Size selective plots of the fiber elimination correlated with fiber diameters enables the mechanism of the fiber elimination (dissolution, fiber breakage, physical clearance) to be interpreted. The half-time of fiber elimination from the lung ranges from about 10 days for wollastonite to more than 300 days for crocidolite. The biodurability of man-made vitreous fibers (MMVF) is between these values and is dependent on the chemical composition of the fibers and the diameter and length distribution. Results indicate that the in vivo durability of glass fibers is considerably longer than expected from extrapolation of published data on their in vitro dissolution rates.

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“…It is not established whether these effects on the lung are a consequence only of the silica present in most bentonites or are a general property of the bentonite mineral mix. Intratracheal administration of bentonite to rats revealed a high cytotoxic potential; however, the acute inflammatory response was short-lived and the cell population returned to normal within few weeks (Sykes et al, 1983;Vallyathan, 1994). These studies did not consider chronic exposure.…”

Section: 3mentioning

confidence: 98%

Scientific Opinion on the safety and efficacy of bentonite as a technological feed additive for all species

2012

EFS2

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Bentonites are colloidal clays composed largely of montmorillonite. They are currently authorised for use as feed additives (binders, anti-caking agents and coagulants) to a maximum of 20 g/kg feedingstuffs. They are also authorised for use as food additives. A consortium is seeking the re-authorisation of bentonites as pellet binders and anti-caking agents and authorisation for a new application for the control of radionuclide contamination. Chickens and piglets tolerated the addition of bentonite at a concentration of 3 % of diet and dairy cows tolerated 2 % added bentonite. Trout are reported to tolerate at least 2.5 % bentonite in the diet. Since the application is for all animal species and all bentonites, and as a margin of safety is difficult to establish, the FEEDAP Panel considers that the presently authorised limit of 2 % of diet should be retained. Addition of bentonites to diets is incompatible with the use of robenidine and is expected to reduce the effectiveness of other coccidiostats. No concerns for the safety of consumers of food products derived from animals fed diets containing bentonite were identified. Bentonites are not skin irritants but may be mildly irritant to the eye. Although skin sensitisation was not considered, the Panel notes that bentonites are used in cosmetics. The Panel considers it prudent to assume that all bentonite dusts pose a hazard to those handling the additive. Bentonites are ubiquitous soil components, and their use in animal production is not expected to adversely affect the environment. Bentonites can increase pellet durability when added to complete feed at concentrations of between 1 % and 2 %. Since bentonites are authorised for use, without restriction, as anti-caking agents in food and can be assumed to demonstrate similar properties when applied to feed materials, no further demonstration of efficacy is considered necessary. Bentonites added to feed contaminated by radioactive fallout or made available to grazing animals will reduce levels of radiocaesium in animals and their products. © European Food Safety Authority, 2012 KEY WORDSTechnological additive, anti-caking agent, binder, substances for control of radionuclide contamination, bentonite, safety, efficacy SUMMARYFollowing a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety, for target animals, consumer, users and the environment, and the efficacy of a group of bentonites. Bentonites are colloidal and plastic clay materials composed largely of montmorillonite (a species of dioctahedral smectite). The properties of bentonites can vary considerably depending on geological origin and any post-extraction modification, and their individual characteristics have a marked bearing on their economic use. Bentonites (E558) are currently authorised for use as feed additives, with the name -Bentonite-montmorillonite‖, as binders, anti-caking agents and coagulants under the category tec...

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The advantages and limitations of an in vivo test system for investigating the cytotoxicity and fibrogenicity of fibrous dusts.

Cited by 12 publications

References 12 publications

Lung response after subchronic glass fiber intratracheal instillation—an experimental study on rats

Lung response after subchronic glass fiber intratracheal instillation—an experimental study on rats

Comparative investigations of the biodurability of mineral fibers in the rat lung.

Scientific Opinion on the safety and efficacy of bentonite as a technological feed additive for all species

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