title: Assessment of the predictive capacity of the 3T3 Neutral Red Uptake cytotoxicity test method to identify substances not classified for acute oral toxicity (LD50>2000 mg/kg): results of an ECVAM validation study.
abstract: Assessing chemicals for acute oral toxicity is a standard information requirement of regulatory testing. However, animal testing is now prohibited in the cosmetics sector in Europe, and strongly discouraged for industrial chemicals. Building on the results of a previous international validation study, a follow up study was organised to assess if the 3T3 Neutral Red Uptake cytotoxicity assay could identify substances not requiring classification as acute oral toxicants under the EU regulations. Fifty-six coded industrial chemicals were tested in three laboratories, each using one of the following protocols: the previously validated protocol, an abbreviated version of the protocol and the protocol adapted for an automation platform. Predictions were very similar among the three laboratories. The assay exhibited high sensitivity (92-96%) but relatively low specificity (40-44%). Three chemicals were under predicted. Assuming that most industrial chemicals are not likely to be acutely toxic, this test method could prove a valuable component of an integrated testing strategy, a read-across argument, or weight-of-evidence approach to identify non toxic chemicals (LD50>2000 mg/kg). However, it is likely to under predict chemicals acting via specific mechanisms of action not captured by the 3T3 test system, or which first require biotransformation in vivo.
authors.affiliation: Institute for Health and Consumer Protection, European Commission Joint Research Centre, 21027 Ispra, Italy. maria.prieto-pilar@jrc.ec.europa.eu
authors.forename: Pilar
authors.initials: P
authors.lastname: Prieto
authors.forename: Thomas
authors.initials: T
authors.lastname: Cole
authors.forename: Rodger
authors.initials: R
authors.lastname: Curren
authors.forename: Rosemary M
authors.initials: RM
authors.lastname: Gibson
authors.forename: Manfred
authors.initials: M
authors.lastname: Liebsch
authors.forename: Hans
authors.initials: H
authors.lastname: Raabe
authors.forename: Anita M
authors.initials: AM
authors.lastname: Tuomainen
authors.forename: Maurice
authors.initials: M
authors.lastname: Whelan
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kinsner-Ovaskainen
mesh_terms: D000826:Animal Testing Alternatives; D000818:Animals; D041702:BALB 3T3 Cells; D002470:Cell Survival / Q000187:drug effects; D004396:Coloring Agents / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D009499:Neutral Red / Q000378:metabolism; D011237:Predictive Value of Tests; D018675:Toxicity Tests / Q000379:methods*; D015262:Xenobiotics / Q000633:toxicity*
chemical_list: D004396:Coloring Agents; D015262:Xenobiotics; D009499:Neutral Red