title: Tumor target organs and rate of survival in long-living transgenic mice and their parental wild-type counterparts exposed to the carcinogen dimethylbenz(a)anthracene.
abstract: Two-year-old mice of the long-living transgenic mice of the alphaMUPA strain were previously found to show higher tumor resistance than the their initial wild-type (WT) strain (Tirosh, 2003). To better understand the mechanism underlying the differences in tumorigenesis rates between the two mouse lines, the rate of tumorigenesis and survival effects were studied in alphaMUPA mice and parental WT mice exposed to dimethylbenz(a)anthracene (DMBA). Each animal received three intragastric feedings of DMBA, each one week apart, at doses of 2, 1, and 1 mg dissolved in 0.2 ml corn oil; thus, the total amount of the carcinogen was 4 mg/mouse. Control mice received corn oil. The alphaMUPA mice exhibited distinctly higher survival rates in experimental chemically-induced tumorigenesis compared to their WT counterparts: 93% vs. 67%, p =2.7. The rate of tumorigenesis differed between the mouse lines (yield was 1.5 and 2.1), owing to a distinct tendency toward decreased tumor frequency in the skin and forestomach in the alphaMUPA mice. The experimental duration was also significantly higher for transgenic mice: 35.9 +/- 1.2 weeks compared to 30.5 +/- 1.3 weeks in WT mice, p <0.01. The lungs, forestomach and skin were target organs for the carcinogenic effect of DMBA. Our observations suggest that aging promotes the rate of spontaneous and induced tumorigenesis.
authors.affiliation: Koret School of Veterinary Medicine, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel.
authors.forename: George
authors.initials: G
authors.lastname: Kossoy
authors.forename: Herzl
authors.initials: H
authors.lastname: Ben-Hur
authors.forename: Ruth
authors.initials: R
authors.lastname: Miskin
authors.forename: Rut
authors.initials: R
authors.lastname: Miskin
authors.forename: Itshak
authors.initials: I
authors.lastname: Zusman
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000008:administration & dosage / Q000633:toxicity*; D000284:Administration, Oral; D000818:Animals; D002273:Carcinogens / Q000008:administration & dosage / Q000633:toxicity*; D008136:Longevity; D008175:Lung Neoplasms / Q000139:chemically induced / Q000401:mortality / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000401:mortality* / Q000473:pathology; D012878:Skin Neoplasms / Q000139:chemically induced / Q000401:mortality / Q000473:pathology; D013274:Stomach Neoplasms / Q000139:chemically induced / Q000401:mortality / Q000473:pathology; D015996:Survival Rate; D013997:Time Factors
chemical_list: D002273:Carcinogens; D015127:9,10-Dimethyl-1,2-benzanthracene