Study On Conducting The Comet Assay And Its Application On The New Drug Safety Evaluation

The comet assay, also known as the single cell gel electrophoresis (SCGE) assay, is a rapid, visual, and highly sensitive technique for determinating DNA breakage in individual cell. Due to its sensitive is similar to Ames test , the technique is becoming a widely used analytical procedure. Based on the comet assay technique established in the test condition of our laboratory, the technique is applied to the new drug safety evaluation. In compliance with the guideline of the test made by Tice (2000), in the study, CHL cells were treated for 2 hr with the Ginsenoside Rg3 freeze-dried powder at three different concentrations (140,70,35μg/ml), negative and positive control groups were performed at the same time with the method. In positive control groups , cells were treated with MMS at two different concentrations (1.1×10-3,11×10-3μg /ml). DNA damage was then determined using the comet assay. Comet graphs of the cells together with associated data indicated that the cells'DNA were not significantly damaged between the negative control group and the treated groups. In positive control groups, comet graphs indicated that comet tail length increased as MMS concentration increased, thereby showing a dose-response relationship and repeatability. Thus, the result indicated that the CHL cells'DNA weren't damaged obviously by the Ginsenoside Rg3 freeze-dried powder.The study concluded that the Ginsenoside Rg3 freeze-dried powder showed no obvious genotoxicity for the CHL cells.