Experimental Chronic Poisoning With Vinyl Chloride (Monochloroethene)

Abstract

After establishing acute toxicity of vinyl chloride, we considered it necessary to carry out a 3 months chronic experiment to see the effects of long-term exposure on animals. We also tried to show the effect of vitamin C on poisoned animals. METHOD OF WORKThe experiment was carried out on 6 groups of 10 guinea pigs each, the animals having about the same age and weight. The guinea pigs were kept under laboratory conditions for 2 weeks, to allow them to accommodate to the environment. The toxic effects were observed on animals with normal feeding and also on other groups fed with an excess of vitamin C . We also wanted to estimate the restoration capacity of animals by interrupting the poisoning. The guinea pigs were exposed to a 10 percent vinyl chloride concentration for 2 h daily, in a gassing chamber of 580 liters. The air was kept in constant motion for a good homogenization of the poison.The first group served as controls and was fed normally.The second group was fed in the same way as the first, but was exposed daily to 10 percent vinyl chloride for 90 days, and then sacrificed.Groups 111, IV, V, and VI were fed normally and 10 mg of vitamin C , in a solution of 20 percent sepharose, was administered orally with a pipette, during 90 days.In these groups, the exposure to poisoning was differentiated. Group 111 was exposed for only 1 month, then kept for 2 months without poisoning, and at the end of the 90 days period the animals were sacrificed. Group IV was exposed for 2 months, not exposed for 1 month, and then sacrificed. Group V was exposed for 3 months to vinyl chloride and sacrificed, and group VI served as a contra1 for groups I11 and V which were exposed but received a supplement of vitamin C .During the experiments the animals were checked monthly for: growth, hematological changes, spontaneous motility, and ascorbinemia. At the end of the 90 days period, specimens were taken for histopathological and histochemical examinations. RESULTSGrowth of animals differs according to the duration of poisoning and vitamin uptake. The guinea pigs from group I1 having 3 months poisoning, without surplus of vitamin C had the slowest growth, as compared with group I, controls, the difference being statistically significant (p < 0.01). The other groups, which had been poisoned and had a surplus of vitamin C behaved as follows. Group V although poisoned for 3 months had a better growth than group 11; but without sig-159

Polyvinyl chloride pneumoconiosis.

“…Our patient was exposed to PVC dust only, while Lilis et al (1975while Lilis et al ( , 1976 showed that PVC dust inhalation induced less severe respiratory function abnormalities than simultaneous inhalation of vinyl chloride monomer and PVC. This must be compared with the results described by Prodan et al (1975), who showed that, in the guinea-pig, two hours' inhalation each day of air containing 10% vinyl chloride monomer over two weeks could produce diffuse pulmonary fibrosis. Further studies of the mechanisms of this pneumoconiosis are in progress.…”

Effect of the CYP2E1 genotype on vinyl chloride monomer-induced liver fibrosis among polyvinyl chloride workers

“…Research has also found that reactive intermediates bind in the liver to proteins, DNA, RNA and lipids, thus eventually impairing liver cell function, inducing cytotoxicity and causing cell necrosis (ATSDR, 2006;Guengerich and Watanabe, 1979). Reactive intermediates were proposed to activate hepatic Kupffer cells and stellate cells, thus eventually leading to liver fibrogenesis (Mastrangelo et al, 2004;Prodan et al, 1975). Recently, liver fibrogenesis was also proposed to be a secondary effect of the initiation of immune responses to cytotoxicity and cell necrosis when protein adducts expressed on the liver cell membrane as neo-antigens (ATSDR, 2006;Robin et al, 1997).…”

Pulmonary effects of polyvinyl chloride dust exposure on compounding workers.

“…Reprint requests to: Dr Ng Tze Pin , Department of Community, Occupational and Family Medicine, National University of Singapore, Lower Kent Ridge, Singapore 0511. VCM has been reported to cause pulmonary fibrosis in animals (10), and PVC dust exposure among workers has been shown to induce less severe respiratory abnormalities than combined exposure to PVC and VCM (3).…”