title: DNA damage, cytotoxic effect and cell-cycle perturbation of Hoechst 33342 on L1210 cells in vitro.
abstract: This study was designed to evaluate the effects of vital dye Hoechst 33342 (HO 33342), at concentrations used to obtain a good DNA histogram resolution, on DNA integrity, cell growth, and cell-cycle phase distribution of L1210 cells. HO 33342 exposure for 2 h, at 37 degrees C produced DNA single-strand breaks as assessed by the method of alkaline elution. DNA single-strand breaks were concentration dependent (in the range .5-5 micrograms/ml) and increased significantly when HO 33342 (0.5-1.5 micrograms/ml) was associated with exposure in a flow cytometer to U.V. laser beam illumination. HO 33342 produced a cytotoxic effect on cell growth even at the concentration of 0.5 microgram/ml--a concentration ten-fold smaller than those required to obtain a good DNA histogram resolution. HO 33342 produced a severe block of the cells in the G2-M phase of the cell cycle already evident 24 h after stain exposure and continuing up to 144 h after start of recovery. A new polyploid cell population (with a 4 c DNA content) not present in the unstained cells was already evident 24 h after dye exposure. The data shown in the present paper would imply caution in using sorted cells stained with HO 33342 dye for biological, biomedical, and pharmacological studies.
authors.affiliation: Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Erba
authors.forename: P
authors.initials: P
authors.lastname: Ubezio
authors.forename: M
authors.initials: M
authors.lastname: Broggini
authors.forename: M
authors.initials: M
authors.lastname: Ponti
authors.forename: M
authors.initials: M
authors.lastname: D'Incalci
mesh_terms: D000818:Animals; D001562:Benzimidazoles / Q000633:toxicity*; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D005434:Flow Cytometry; D007834:Lasers / Q000009:adverse effects; D007939:Leukemia L1210 / Q000473:pathology*; D051379:Mice; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D001562:Benzimidazoles; D004247:DNA; C017807:bisbenzimide ethoxide trihydrochloride