Occurrence and morphology of tumors induced in nude mice transplanted with chrysotile‐transformed rat pleural mesothelial cells

Abstract

Rat pleural mesothelial cells treated in vitro with chrysotile fibers have been successfully transplanted into nude mice. Three cultures (1 untreated, 2 treated) were injected at passage 75; a fourth culture was obtained from a mesothelioma induced in rat by chrysotile fibers. Overall, tumors grew in each series, but the delay between cell injection and tumor formation was 22 wk with untreated cells whereas only 1 or 2 wk were needed with treated cells, and 1 wk with cells from in vivo-induced mesothelioma. Pathological study by light and electron microscopy of tumors is reported here and showed the mesothelial nature of the cells. Comparison between the ultrastructure of the injected cells and tumor cells indicated that the morphology of injected cells was retained in tumors even if the delay in tumor formation was long. These results suggest that this model is useful for investigating mesothelial cell transformation resulting from in vitro or in vivo exposure to certain carcinogens.

Pleuro-pulmonary tumours detected by clinical and chest X-ray analyses in rats transplanted with mesothelioma cells

“…The tumours were fixed in 10% formal in for anatomo-pathological examination or in glutaraldehyde in cacodylate buffer for electron microscopy studies, according to standard procedures (Fleury-Feith et al, 1989). Immunohistochemistry of tumours was performed to investigate keratin expression.…”

“…Crocidolite fibres were provided by the Union Internationale Contre le Cancer. After tumour excision, mesothelioma cells were cultured according to standard conditions in RPMI-1640 (Gibco BRL, Life Technologies, Cergy Pontoise, France) supplemented with 8% fetal bovine serum (FBS; Biological Industries, ATGC, Noisy le Grand, France), penicillin and streptomycin, both from Gibco BRL as described elsewhere (Fleury-Feith et al, 1989). After several passages to obtain a sufficient number of cells, these were frozen in complete RPMI-1640 containing 10% dimethyl sulphoxide (Sigma, Saint Quentin Fallavier, France) and stored in liquid nitrogen.…”