Acute cytotoxicity testing with cultured human lung and dermal cells

Area of Science:

• Toxicology
• Cell Biology

Background:

• The basal cytotoxicity theory posits that chemical injury in vitro results from insults to common mammalian cellular structures and functions.
• This theory may explain the consistency observed in multi-laboratory toxicity studies.

Purpose of the Study:

• To evaluate the potential of human cell lines for screening chemical cytotoxicity.
• To test the basal cytotoxicity theory using human fibroblasts.

Main Methods:

• Human fetal lung (HFL1) and skin fibroblasts (WS1, Detroit551) were cultured.
• Cells were exposed to 29 chemicals at varying concentrations for 24 hours.
• The MTT assay measured toxicity, and inhibitory concentrations (IC50) were determined via linear regression.

Main Results:

• Experimental IC50 values from human fibroblasts accurately predicted human toxicity, comparable to rodent LD50 data.
• No significant differences in cytotoxicity were observed among the three human cell lines tested.
• The findings support the basal cytotoxicity phenomenon, explaining inter-laboratory consistency.

Conclusions:

• Finite human cell lines are suitable for screening chemicals for human toxicity.
• The basal cytotoxicity theory provides a framework for understanding consistent in vitro toxicity results across different human cell lines.