In vitro cytotoxicity assays: Comparison of LDh, neutral red, MTT and protein assay in hepatoma cell lines following exposure to cadmium chloride

Introduction:
This text is a summary of a study comparing four in vitro cytotoxicity assays and their ability to detect early cytotoxic events in hepatoma cell lines following exposure to cadmium chloride. The assays compared are the lactate dehydrogenase leakage assay (LDh), a protein assay, the neutral red assay, and the methyl tetrazolium (MTT) assay.

Key points:

* The study used two hepatoma cell lines, hTC and hepG2, and exposed them to cadmium chloride for 3, 5, and 8 hours.
* Cytotoxicity was determined using the LDh leakage assay, a protein assay, the neutral red assay, and the MTT assay.
* The neutral red assay and the MTT assay were found to be the most sensitive in detecting cytotoxic events compared to the LDh leakage and protein assay.
* In hTC cells, no toxicity was observed for any incubation period when the LDh leakage, the MTT and the protein assay were employed, whereas the neutral red assay revealed early cytotoxicity starting after incubation of hTC cells with CdCl2 for 3 hours.
* In hepG2 cells, the MTT assay revealed cytotoxicity due to CdCl2 exposure after 3 hours, whereas no such effect was seen with the other three assays. Following 5 hours exposure of hepG2 cells to CdCl2, toxicity was observed with the MTT assay at lower concentrations compared to the ones required for detection of toxicity with the LDh leakage and the neutral red assay.

Main message:
The study highlights the importance of using sensitive cytotoxicity assays to detect early cytotoxic events in vitro. The neutral red and MTT assays were found to be more sensitive than the LDh leakage and protein assay in detecting cytotoxicity in hepatoma cell lines following exposure to cadmium chloride. This information can be useful in the development and regulatory evaluation of chemicals and drugs. It is important to consider the appropriate assay to use depending on the specific study objectives and the properties of the test compound.

Fotakis, George, and John a. Timbrell. “In Vitro Cytotoxicity assays: Comparison of LDh, Neutral Red, MTT and Protein assay in hepatoma Cell Lines Following Exposure to Cadmium Chloride.” Toxicology Letters 160, no. 2 (January 2006): 171–77. https://doi.org/10.1016/j.toxlet.2005.07.001.