Ł u in ... - : - .. . I OF L ORNLP 2287 . ... I PM 1. . -- 245 met SO B56 11 1 eport. MALE MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS - 1963 . . ornaf-2287 si 12..., II. : /.00; MN 50 1 For proceedings of the International Colloquium on Radiation and Aging (Vienna, Austria, June 23-24, 1966) AUG 10 1966 WWF-6606635 --D RELEASED FOR ANNOUNCEMENT. IN NUCLEAR SCIENCE ABSTRACTS MASTER Influence of Age at Irradiation on Susceptibility to Radiation-Induced Life-Shortening in RF Mice A. C. Upton, J. W. Conklin, and R. A. Popp Biology Divieion, Oak Ridge National Laboratory Oak Ridge, Tennessee LEGAL NOTICE This report was prepared as an account of Government sponsored work. Neither the United Suatos, por the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representation, expressed or implied, with respect to the accu- racy, completeness, or usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this roport may not Infringo privately owned rights; or B. Assumes any liabilities wild respect to the use of, or for damages resulting from the use of any information, apparatus, method, or procesu disclosed in this report. As used in the above, "person acting on behalf of the Commission" incljes any ome ployee or contractor of the Commission, or employee of such contractor, in the extent that soch omployet or contractor of the Commission, or employee of such conl'actor prepares, dissominates, or provides access to, any information pursuant to his employment or contract with the Commission, or his employment with such contractor. < ? . ,- . R Running head: AGE AND LIFE-SHORTENING Send proof to: Dr. Arthur C. Upton Biology Division Oak Ridge National Laboratory P. 0. Box Y Oak Ridge, Tennessee 37830 - - - . PE INTRODUCTION The influence of age on susceptibility to radiation-induced life- shortening is of theoretical and practical interest. To explore this question, we have analyzed effects of x-irradiation on the life-expect- ancy cf RF mice irradiated at widely differing ages. The preliminary results of this analysis are summarized in the following. METHODS Non-inbred male and female RF mice of the Oak Ridge subline were exposed to 50-400 R whole-body x rays at ages ranging from 9-1/2 days after conception to 1 year after birtis. Irradiation in utero was carried out at a) 9-1/2, b) 12-1/2 and 14-1/2, and c) 17-1/2 days after conception, to expose the hemopoietic system at stages of development when blood formation was found to be localized predoninantly in the a) yolk sec, b) liver, and c) marrow and spleen respectively. Fetal irradiation was carried out by whole-body exposure of pregnant mice at the stages in gestation and to the doses in question. Each dose- and age-group contained 20-200 mice of a given sex. The factors of irradiation were 80-100 R/min with back-scatter, 250-300 Kvp, 30 ma, 93.7 cm TSD, 3 mm Al filtration (Be window), and 0.44 mm Cu HVL. After weaning, males and females were housed separately in plastic cages in groups of 10, maintained at a room temperature of 24 + 1°C and at a relative humidity of 50%, and given free access to purina laboratory chow and drinking water. Each mouse was observed throughout life and necropsied after death. RESULTS The life-expectancy decreased with increasing dose, irrespective of sex and age at irradiation (Figs 1-3). The life-shortening was, in general, most marked in the mice exposed at 30-40 days of age and least marked in those exposed at 1 year of age. Paradoxically, however, the effects - - were also minimal in those exposed prenatally, except for the males exposed to 300 R at 14-1/2 days following conception, which showed a mean survival time of only 190 days (Fig 4). Because the shortening of life was so drastic in this group, the irradiation of 14-1/2 day-old fetuses was repeated, with essentially identical results the second time (Fig 4). Exposure to 300 R at 9-1/2 days after conception or to larger doses at 1.2-1/2 to 17-1/2 days after conception was not carried out because it resulted in high intrauterine lethality. None of the groups reported herein, however, showed evidence of prenatal or neonatal mortality attributable to irradiation. The diseases observed in association with life-shortening were similar to those reported earlier in mice of the same strain (see Upton et al, 1954; Conklin et al, 1965). The males dying within 1 year after exposure to 300 R at 14-1/2 days following conception, however, failed to show the spectrum of lesions typical of aging RF males. Instead, they manifested stunting of body growth, microcephaly, hyperirritability, a tendency toward ulcerative dermatitis (possibly from fighting or from mite infestation), and premature onset of intercapillary glomeruloscle- rosis (Fig 5), with signs suggestive of incipient periarteritis. There was no detectable increase in the incidence of leukemia or solid tumors in this or any other group of prenatally exposed mice. DISCUSSION The decrease in life-shortening with increasing age after weaning agrees with earlier observations in mice (see Boone, 1960; Lindop and Roblat, 1962, 1965; Kohn and Guttman, 1959, 1963) and rats (Jones and Kimeldorf, 1964). Although the reduced response of our one-year-old mice may be partly ascribed to their failure to survive the long induc- tion period (F48 6) for the life-shortening effects in question' (see also Kohn and Guttman, 1959; Neary, 1960; Johnson, 1964; Storer, 1965), the induction period in our younger age groups differed enough to suggest the existence of age-dependent variations in susceptibility per se (Fig 6). Additiona). evidence of age-dependent variations in - V - T susceptibility not explicable in terms of the long induction period alone - - T has been reported by others (see Jones and Kimeldorf, 1964; Lindop and . Rotblat, 1965). Age differences in life-shortening may be expected to *miocienci be particularly large when the effects on survival depend on induction of a specific disease the susceptibility to which varies markedly with age; e.g., thymic lymphoma (see Kaplar, 1948; Upton, Odell, and Sniffen, 1960) and intercapillary glomerulosclerosis (see Guttman and Kohn, 1963). The reduced susceptibility observed in our aging mice is, therefore, being analyzed in relation to the age-distribution and incidence of radiation-induced diseases in the different age groups. The relatively low susceptibility of fetal mice to radiation-induced life-shortening, except in the case of the males exposed to 300 R at 14-1/2 days after conception, was unexpected and cannot yet be accounted for. It contrasts with the apparently high susceptibility of fetal rats de arthrazension " . . 114 - _=" * . - - * - * . - - * - .. : . 7 . . . . to radiation-induced life-shortening (Rejacke et al, 1964). The marked life-shortening in the males exposed to 300 R at 14-1/2 days of age was, likewise, unexpected and remains to be explained. Although it was associated with stunting of growth, microcephaly, hyperirritability, chronic ulcerative dermatitis, giomerulosclerosis, and signs suggestive of incipient polyarteritis, the possible role of these lesions in its pathoger osis is unknown. By themselves, the glomerulosclerosis and asecuiated arteritis appeared too mild to have contributed to death. Moreover, these lesions occurred to the same extent in females, which . . . . did not show drastic life-shortening, as in males. The absence of carcinogenic or leukemogenic effects of prenatal irradiation in our animals, although consistent with earlier observations in mice of the same (Upton, Odell, and Sniffen, 1960) and apparently other (Rugh et al, 1966) strains, contrasts with results observed in rais (Reincke et al, 1964) and with the implications of epidemiological studies in man (see Mac Mahon and Plutchison 1964). Likewise, the lowered -... .- :-.- susceptibility of aging rodents to the life-shortening and carcinogenic effects of radiation appears to conflict with certain preliminary data on the response of human populations to the leukemogenic effects of radiation as influenced by age (see Upton, 1964). These differences call for further study, with a view toward clues they may possibly provide concerning mechanisms of the life-shortening and oncogenic effects in quesiion. SUMMARY - Non-inbred male and female RF mice were exposed to 50-400 R whole- PE body x rays at ages ranging rom 9-1/2 days after conception to 1 year 1 , after birth. In mice of both sexes, irradiation after birth shortened the 11?e span, the effect per unit dose being largest at the higher dose levels (300-400 R) and in the groups exposed at 40-70 days of age. In mice exposed before birth, life-shortening was consistently less marked ther in those exposed after birth, except in the males irradiated early in development at the highest dose level administered prenatally (i.e., 300 R at 14-1/2 days after conception). These males died with runting and microcephaly after a mean survival time of only 6-7 months from causes yet to be determined. They failed to show the typical spectrum of neoplastic and non-neoplastic lesions associated with life-shortening and aging in the other groups. The relatively low susceptibility of &11 other prenatally irradiated mice to radiation-induced life-shortening and carcinogenesis is paradoxical and remains to be explained. ACKNOWLEDGMENT . Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. :: ! # BOT REFERENCES Boone, Irene U. 1960. Incidence of Tumors in Animals Baposed to Whole Body Radiations. ORO-SP-127 pp. 1937. Conklin, J. W., Upton, A. C., and Christenberry K. W. 1965. Purther Observations 'on Late Somatic Effects of Radiomimetic Chemicals and X-Rays in Mice Gude, W. D. and Upton, A. C. 1960. Spontaneous Glomerulosclerosis in Ag:ing RF Mice. Journal of Gerontology, 15: 373-376. Guttaan,P. H., and Kohn, H. I. 1963. The Mouse Kidney After X-irradiation in Early Postnatal Life. A Study of Immediate and Delayed Effects and Their Dependence on Celluler Differentiation and Organ Süructure at the Time of Exposure. American Journal of Pathology, 43(5): 809-824. Johnson, Horton A. 1964. Age and Sensitivity to Radiation Life Shortening. Radiation Research, 23: 19-25. Jones, David C.L., and Kimeldorf, D. J. 1964. Effect of Age at Irradiation on Life Span in the Male Rat. Radiation Research, 22: 106-115. Kaplan, H. S. 1948. Influence of Age on Susceptibility of Mice to the Development of Lymphoid Tumors after Irradiation. Journal of the National Cancer Institute, 9: 55-56. Kohn, H. I., and P. H. Guttman, 1959. Latent Period of X-Ray Induced Ageing: a Study Based on Mortality Rate and Tumor Incidence. Nature , 184: 735-736. Koha, Henry I., and Paul H. Guttman. 1963. Ace at Bxposure and the Late Befects of X-Rays. Burvival and Tudor Incidence in CAF, Mice Irradiated at 1 to 2 Years of age. Radiation Research 18: 348-373. Lindop, Patricia J., and Rotblat J. 1962. The Age Factor in the Susceptibility of Man and Animals to Radiation. I. The Age Factor in Radiation Sensitivity in Mice. British Journal of Radiology., 35(409): 23-31. Lindop, Patricia J. and Rotblat J. 1965. Life-Shortening in Mice Exposed 1070-1072. MacMahon, B., and G. B. Hutchinson. 1964. Prenatal X-Ray and Childhood. Cancer: A Review. Acta Unio Internationalis Contra Cancrum, 20: 1172-1174. .: Storer, John B. 1965. Radiation Resistance with Age in Normal and Irradiated Populations of Mice. Radiation Research, 25: 435-459. Reincke, U., E. Stutz and G. Wegner 1964. Tumoren nach einmaliger Rontgenbestrahlung weiber Ratten in verschiedenem Lebensalter. Zeitschrift fur Krebsforschung, 66: 265-186. - Rugh, R.; Duhamel, L. and Skaredoft, L. 1966. Relation of Embryonic and Fetal X-Irradiation to Lite Time Average Weights and Tumor Incidence in Mice. Proc. society for Experimental Biolory and Medicine, 121(3): 714-718. - 12 1 Upton, A. C., Purth, J., and Christenberry, K. W., 1954. Late Effects of Thermal Neutron Irradiation in Mice. Cancer Research, 14: 682-90. BI Upton, A. C., T. T. Odell, Jr., and E. P. Sniffen. 1960. Influence of Age at Time of Irradiation on Induction of Leukenia and Ovarian Thumors in RF Mice. Proceedings of the Society for Experimental Biology and Medicine, 204: 769-772. Upton, A. C. 1964. Comperative Aspects of Carcinogenesis by Ionizing Radiation. National Cancer Institute Monograph No. 14: 221-242. LEGENDS FOR FIGURES 1. Mean survival time of females in relation to magnitude of exposure and age at irradiation O Fixposure 7-11 days before birth; 1.e., 9-1/2 to 12-1/2 days.'" after conception (225-250 mice per group). Exposure 1-3 days before birth; i.e. 17--1/2 to 19-1/2 days after conception (225-300 mice per group). O OD Exposure 1-9 days after birth (75-150 mice per group). Exposure at 30-40 days after birth (40-50 mice per group). Exposure at 70 days after birth (45-100 mice per group). 0 Exposure at 180 days after birth (39–100 mice per group). Exposure at 365 days after birth (37-45 mice per group). 2. Mean survival time of males in relation to exposure dose and age at irradiation. (Symbols same as in Fig 1.) 3. Cumulative mortality in relation to age in fernales exposed to 400 R, · or sham-irradiated, at varying ages. (Symbols same as in Fig 1; shaded symbols denote controls.) 12 .. 4. Cumulative mortality in males exposed to 300 R at 14 1/2 days after conception. First experiment (exposure in 1961). Second experiment (exposure in 1963) for rent Pooled controls. 5. Severity of glomerulosclerosis in relation to age. Males and females exposed to 300 R at 14-1/2 days after conception. ca Nonirradiated controls. (including data of Gude and Upton, 1960). : 6. Cumulative mortality in relation to time after irradiation in females exposed to 400 R, or sham-irradiated, at varying ages. (Symbols same as in Fig 3.) . t : همه INUTES له - مه MAT SORTIVAL TIS (DAS) - - - - - ه م 100 . 200 . 200 APOSTRE (R) . . . . . . ... C . - MATES -- < ------3to - 500 -- BEAJ SIRVITAL IDE (DALS) --- 200 300 200 ) SIPOSURE 1001 400 R FEMIDES Litom CUMULATIVE MORTALITI (8) --AAAAAAAB- Doo 200 300 200. 500 ia 600 (DAYS). 700 800 900 2000 2000 HES sor 300 R et 14 days arte conceptiar Central CUMULATIVE MORTALITI (5) 200 200 400 500 600 700 800 900 . . 103 (ATS) GIOVORULOSCIEROSIS 300 R at 14 dagi ATGRAGS SLVRITI OF ILSION CONTROLS ACES CONTES) - - - ... - - - -- - - - * ..* . * EE RA 200 maa-to 400 R FEMALES (8) ITIVIWOW TAIWup ! O do 100 200 300 600 400 500 TDR UTER PREDIATTON (DATS) 700 700 800 . . .. - - jäi - -- Yes - - *.-- . :-. .. . * - - - YA - - - . . - - -= y - - - .. 12 ." SO : - - -- Huu .. . 04 . END DATE FILMED 9/9 166 S- * - i. ...mi