in vitro cytotoxicity

/Tag:in vitro cytotoxicity

Acute Oral Toxicity Testing: Scientific Evidence and Practicability Should Govern Three Rs Activities

Roland Buesen, Uwe Oberholz, Ursula G. Sauer and Robert Landsiedel

Acute oral toxicity is determined for regulatory hazard classification or non-classification. The European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) recommends the following modules for acute oral toxicity testing: a) the use of the in vitro 3T3 Neutral Red Uptake (NRU) test to identify substances not requiring classification and to estimate starting doses for in vivo acute oral toxicity studies; and b) the use of data from sub-acute toxicity studies to identify substances not requiring classification. However, the application of these modules in a regulatory context would require a predefined, validated and formally accepted testing strategy and data interpretation procedure, which are not available. Furthermore, the application of the 3T3 NRU assay for starting dose estimations could in fact increase the number of animals used. Finally, only very few substances exist for which data from sub-acute or other repeated dose studies are available, but data from acute studies are not. Therefore, in practice, the prediction of acute toxicity by using sub-acute toxicity data is generally irrelevant. It could even lead to a risk of overdosing in the range-finding study, which may result in the death of many or all of the animals used.

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In Vitro Assessment of Cytotoxicity and Carcinogenic Potential of Chemicals: Evaluation of the Cytotoxicity Induced by 58 Metal Compounds in the Balb/3T3 Cell Line

Francesca Mazzotti, Enrico Sabbioni, Michela Ghiani, Barbara Cocco, Raffaella Ceccatelli and Salvador Fortaner

A new, mechanistically based, in vitro strategy involving Balb/c 3T3 clone A31-1-1 mouse embryo fibroblasts has been proposed for the determination of the carcinogenic potential of inorganic chemicals, in order to establish priority of metal compounds to be tested and, whenever possible, to compare the in vitro results with the corresponding in vivo data. As a first step in this research, this study reports on the cytotoxic effects of 58 metal compounds in the Balb/3T3 cell line. After harmonisation and standardisation of the Balb/3T3 protocol, cells were exposed for 72 hours to a fixed dose (100μM) of 58 individual compounds. The cytotoxicity induced by some metal compounds was found to be related to their chemical form (for example, Cr(NO3)3 and Na2CrO4), suggesting that the Balb/3T3 cell line is a valuable cellular model in relation to this aspect of metal speciation. The results of the systematic study on the metalinduced cytotoxic effects in the Balb/3T3 cell line could be arbitrarily classified into three groups according to the degree of cytotoxicity. Group I includes 26 species that induced no observable effect or only a slight cytotoxic effect; Group II includes 13 metal compounds that exhibited an obvious degree of cytotoxicity; and Group III includes 19 metal species that displayed a strong cytotoxic response. Metal compounds of Groups II and III are considered to be of the highest priority for setting of dose–effect relationships for a subsequent in vitro study on metal-induced concurrent cytotoxicity and morphological transformation in the Balb/3T3 cell line.
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