title: Assessment of 5-fluorouracil and 4-nitroquinoline-1-oxide in vivo genotoxicity with Pig-a mutation and micronucleus endpoints.
abstract: Genotoxicity assessments were conducted on male Sprague Dawley rats treated with 5-fluorouracil (5-FU) and 4-nitroquinoline-1-oxide (4NQO) as part of an international validation trial of the Pig-a mutant phenotype assay. Rats were orally exposed to 0, 11.5, 23, or 46 mg/kg/day 5-FU for three consecutive days (Days 1-3); blood was sampled on Days -1, 4, 15, 29, and 45. Pig-a mutant phenotype reticulocyte (RET(CD59-)) and mutant phenotype erythrocyte (RBC(CD59-)) frequencies were determined on Days -1, 15, 29, and 45, and percent micronucleated reticulocytes (%MN-RET) were measured on Day 4. Rats were treated with 4NQO for 28 consecutive days by oral gavage, at doses of 1.5, 3, or 6 mg/kg/day. RBC(CD59-) and RET(CD59-) frequencies were determined on Days -1, 15, and 29, and MN-RET were quantified on Day 29. Whereas 5-FU was found to increase %MN-RET, no significant increases were observed for RBC(CD59-) or RET(CD59-) at any of the time points studied. The high dose of 4NQO (6 mg/kg/day) was observed to markedly increase RBC(CD59-) and RET(CD59-) frequencies, and this same dose level caused a weak but significantly elevated increase in MN-RET (approximately twofold). Collectively, the results provide additional support for the combination of Pig-a mutation and MN-RET into acute and 28-day repeat-dose studies.
authors.affiliation: National Shanghai Center for New Drug Safety Evaluation and Research, China State Institute of Pharmaceutical Industry, Shanghai, China.
authors.forename: Changhui
authors.initials: C
authors.lastname: Zhou
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Huang
authors.forename: Honggang
authors.initials: H
authors.lastname: Tu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Dertinger
authors.forename: Dorothea K
authors.initials: DK
authors.lastname: Torous
authors.forename: Yan
authors.initials: Y
authors.lastname: Chang
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000633:toxicity*; D000818:Animals; D018957:CD59 Antigens / Q000235:genetics*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects; D005472:Fluorouracil / Q000633:toxicity*; D008297:Male; D015162:Micronucleus Tests / Q000379:methods*; D009154:Mutation; D017207:Rats, Sprague-Dawley; D012156:Reticulocytes / Q000187:drug effects; D023382:Toxicity Tests, Acute / Q000379:methods
chemical_list: D018957:CD59 Antigens; D015112:4-Nitroquinoline-1-oxide; D005472:Fluorouracil
keywords: 4-nitroquinoline-1-oxide; 5-fluorouracil; Pig-a; flow cytometry; genotoxicity; mutation