Toxicity of 20 Chemicals from the MEIC Programme Determined by Growth Inhibition of L-929 Fibroblast-like Cells

Area of Science:

• Toxicology
• Cell Biology
• Pharmacology

Background:

• The Multicentre Evaluation of In vitro Cytotoxicity (MEIC) programme assesses the predictive value of in vitro toxicity tests for human health.
• In vitro cytotoxicity assays are crucial for screening chemicals, pharmaceuticals, and medical devices.

Purpose of the Study:

• To screen 20 chemicals (MEIC codes 31-50) using a cytotoxicity test based on L-929 mouse fibroblast cell line growth inhibition.
• To evaluate the neutral red uptake method for its effectiveness in determining chemical cytotoxicity.

Main Methods:

• Utilized a cytotoxicity test employing the mouse fibroblast-like L-929 cell line.
• Measured inhibition of cell growth via the neutral red uptake method after a 72-hour exposure period.
• Screened 20 chemicals with varying concentrations to determine the 50% inhibitory concentration (IC50).

Main Results:

• A wide range of toxicities was observed, with IC50 values from 3.1μM (hexachlorophene) to 1.4mM (caffeine).
• Results were comparable to those obtained with five other cell models, indicating general applicability.
• Challenges were encountered with volatile and poorly soluble chemicals (chloroform, carbon tetrachloride, dichloromethane), hindering reproducible results.

Conclusions:

• The neutral red uptake method with L-929 cells provides a viable approach for assessing chemical cytotoxicity.
• The study highlights the need for careful solvent selection and handling procedures for volatile compounds in cytotoxicity testing.
• Further refinement of methods is necessary to reliably assess the toxicity of challenging chemical substances.