In Vitro/In Vivo DNA Damage and Repair

Primary DNA damage represents possible premutational events that can be detected, either directly or indirectly, by a number of techniques using mammalian cells in culture or using rodent tissue. The unscheduled DNA synthesis (UDS) assay measures the ability of a test article to induce DNA lesions by measuring the increase in DNA repair.

Autoradiography permits the visualization of DNA repair in cultured rodent hepatocytes. Sister chromatid exchanges (SCEs) represent the exchange, requiring breakage and reunion, of DNA replication products at apparently homologous loci of sister chromatids. Differential staining techniques allow visualization and rapid identification of the exchanges in cultured mammalian cells, as well as in rodent bone marrow or spermatogonial cells.

The COMET assay, also known as single cell gel electrophoresis (SCG), is a microgel DNA electrophoresis technique that detects DNA damage and repair in individual cells. The COMET assay is conducted in both in vitro and in vivo systems and is increasingly being used in genotoxic testing.

At MDS we offer the following services:

• In Vitro Unscheduled DNA Synthesis (UDS) in primary rat hepatocytes
• In Vivo Unscheduled DNA Synthesis (UDS) in rat and/or mouse liver
• In Vitro COMET Assay/DNA Damage Assay in CHO, V79, or HPBL
• In Vivo COMET Assay/DNA Damage Assay in rodents
• DNA damage to germ cells, detection of single strand breaks
• DNA damage to germ cells, detection of cross-links
• In Vitro Sister Chromatid Exchange (SCE) in CHO cells
• In Vitro Sister Chromatid Exchange (SCE) in human peripheral lymphocytes
• In Vivo Sister Chromatid Exchange (SCE)