Genotoxicity Analysis Service

Genotoxicity refers to those that cause heritable changes in the chromosomes of germ cells. In early toxicity tests, the detection of a drug's genotoxicity is usually consistent with the detection of its carcinogenic toxicity, because this genetic mutation can also cause cancer. Genotoxicity may have more serious consequences than other organ toxicity, because it is related to gene mutation and chromosomal aberrations and can be amplified or inherited. Genotoxicity includes changes in DNA structure and DNA damage that does not involve structural changes. Therefore, the detection items of genotoxicity test mainly include gene mutation, chromosome structure and number abnormalities, single/double strand breaks of DNA and so on.

With advanced experimental equipment and professional technical team, Creative Biolabs can provide genetic toxicity testing services that required by all kinds of relevant laws. With rich experience in providing genotoxicity and pharmaceutical quality research for pharmaceutical companies, Creative Biolabs focuses on providing a series of complete solutions such as assessment reports and method development for toxicity detection during drug development, and has established a scientific genotoxicity analysis database.

We provide but are not limited to:

Bacterial reverse mutation assay. The bacterial reverse mutation assay uses salmonella typhimurium strain and e. coli that require certain amino acids to detect point mutations, involving the replacement, insertion, or deletion of one or more base pairs of DNA. The principle of this experiment is to detect the response of experimental strain to existing mutations, and the ability of bacteria to synthesize essential amino acids. Reverse-mutated bacteria were detected by growth on a medium lacking the amino acids needed for the strain.

Salmonella typhimurium method (Ames test). Mutagen enables salmonella histidine deficient mutants to revert to the wild type and grow on histidine free media. Therefore, the number of colonies generated on the medium without histidine can be used to determine whether the drug is a mutagenic agent. (Figure 1)
The strains include salmonella typhi (his^-) TA98, TA100, TA1535, TA1535 and e. coli WP2 uvrA (typ^-). Strains TA102 and TA1538 can be used for toxicity assessment of specific compounds. The flat plate incorporation method or the pre-culture method can be selected.

Figure. 1 Ames test

In vitro chromosome aberration test. The purpose of in vitro chromosomal aberration test is to detect chromosomal structural aberrations in cultured mammalian cells. The structural aberrations can be divided into two types: chromosome-type aberration and chromatid-type aberration. Most chemogenic mutants induce chromatid-type aberration, but chromosome-type aberration can also occur. The increase of polyploid indicates that the drug may cause chromosome number aberration. However, this method is not used to detect numerical aberration.

Chr-v1.0 in vitro chromosome aberration kit. With or without the metabolic activation system, the cultured mammalian cells are exposed to drug. After treatment with colchicine, which stops the cells dividing in the metaphase phase, the cells are harvested, sectioned and stained. The researchers analyze whether the drug induce chromosomal aberrations in cultured mammalian cells, further evaluating the possibility of mutagenesis.

Micronucleus test. Micronucleus is marked by double-stranded DNA breaks (chromosome fragments) or damage to mitotic organs (chromatids). Cytokinesis blocking micronucleus can identify cells that have completed division. Cytochalasin B (CYB) is used to block cytokinesis in this method. Chinese hamster ovary (CHO) cells can be used to detect the genotoxicity such as gene mutation and chromosome breakage.
Comet assay. The comet assay, also known as single-cell gel electrophoresis (SCGE), is a sensitive and rapid technique for quantitative analysis of single-cell DNA damage. This technique is being used in the field of new drug research and development to assess the genotoxicity. SCGE can be used to detect DNA damage caused by double-strand breaks, single-strand breaks, alkali instability sites, oxidative base damage, DNA cross-linked DNA and proteins. SCGE can also be used to detect DNA repair in living cells.

DNA is unwound under alkaline/neutral conditions and then subjected to electrophoresis, where broken or damaged DNA fragments are removed from the nucleus. After staining with DNA-specific fluorescent dyes (e.g. Ethidium bromide and propidium iodide), the degree to which the DNA deviates from the comet's head is proportional to the amount of DNA damaged. (Figure 2)

Figure. 2 Comet Assay

The popular services：

The high-throughput screening (HTS) and high-content screening (HCS) platform is a comprehensive solution for full-automatic, high-speed and high-resolution imaging screening, which can meet a variety of needs in the development of new drugs. The platform captures a large amount of information about genes, proteins and other cellular components in a single experiment to determine their biological activity and potential toxicity. This platform based on high-throughput screening and high-content screening is a common technical platform for drug genotoxicity evaluation.

The Creative Biolabs HTS/HCS platform is equipped with a variety of advanced equipment and data processing system to achieve the full automation of living cell screening, providing strong support for a reliable study of genotoxicity.

Advantages of genotoxicity detection services:

Strong technical and management team.
Professional integration of the service platform.
Database of genotoxicity detection methods.
Continuous technological innovation.

References

Galloway SM. International regulatory requirements for genotoxicity testing for pharmaceuticals used in human medicine, and their impurities and metabolites. Environ Mol Mutagen. 2017, 58(5):296–324.
Pu X, et al. Alkaline Comet Assay for Assessing DNA Damage in Individual Cells. Curr Protoc Toxicol. 2015, 65:3.12.1–3.12.11.
Shuai Z L, et al. Review of high-content screening applications in toxicology. Archives of Toxicology, 2019, 93(12): 3387-3396.

*For Research Use Only. Not for use in diagnostic procedures.

Online Inquiry