Sodium sarcosinate

This technique permits the detection and an evaluation of single-stranded DNA breaks. Eukaryotic cells are embedded in agarose gel on a microscopic slide, lysed by detergents and high salt at pH 10, and then electrophoresed for damage display which shows increased migration of the DNA from the nucleus towards the anode. Low-melting temperature agarose and ultra pure a garose, Triton X-100, sodium sarcosinate, ethylenediamine-tetra acetic acid disodium salt (Na-EDTA), Trizma base and ethidium bromide were obtained from Sigma Chemical Co. (St. Louis, MO, USA). Phosphate buffered saline without calcium and magnesium, RBMI 1640 medium (Gibco-BRL, Gaithersburg, MD, USA), Ficoll separating solution and trypan-blue were used in comet assay. Examination was done with a fluorescent microscope (BX 41, Olympus, Tokyo, Japan) equipped with an excitation filter of 510 nm and barrier filter of 590 nm. The migration was evaluated by observing and measuring the nuclear DNA, and 500 spots of DNA were examined and classified into three types: 1) normal spots with round shape; 2) damaged spots in which the length of the migrated fragments was less than or equal to the diameter of the basal nuclear DNA; and 3) strongly damaged spots where the length of the comet was greater than the diameter of the basal nuclear DNA [19 (link)].