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Cooper TK, Meyerholz DK, Beck AP, Delaney MA, Piersigilli A, Southard TL, Brayton CF. Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits. ILAR J 2022; 62:77-132. [PMID: 34979559 DOI: 10.1093/ilar/ilab022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/12/2021] [Indexed: 12/31/2022] Open
Abstract
Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.
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Affiliation(s)
- Timothy K Cooper
- Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA
| | - David K Meyerholz
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Amanda P Beck
- Department of Pathology, Yeshiva University Albert Einstein College of Medicine, Bronx, New York, USA
| | - Martha A Delaney
- Zoological Pathology Program, University of Illinois at Urbana-Champaign College of Veterinary Medicine, Urbana-Champaign, Illinois, USA
| | - Alessandra Piersigilli
- Laboratory of Comparative Pathology and the Genetically Modified Animal Phenotyping Service, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Teresa L Southard
- Department of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Cory F Brayton
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Hard GC. Confounders for kidney carcinogenesis in rodent cancer bioassays. J Toxicol Pathol 2022; 35:1-6. [PMID: 35221490 PMCID: PMC8828606 DOI: 10.1293/tox.2021-0000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 09/29/2021] [Indexed: 11/24/2022] Open
Abstract
In the long-term safety testing of chemicals for carcinogenicity the toxicologist needs
to be aware of a number of scenarios where renal tubule tumors, or their precursors, arise
that are not due to a carcinogenic action of the test article. Situations producing false
positive results in the kidney include exacerbation of chronic progressive nephropathy
(CPN) in rats, confusion of atypical tubule hyperplasia (the obligate precursor of renal
tubule tumor) with foci of benign CPN-related renal tubule cell proliferation, inclusion
of spontaneous tumor entities, such as the amphophilic-vacuolar tumor, in the test article
tumor count, the possibility of a link between spontaneous forms of tubule dilatation and
renal tubule tumor formation in mice, and the supposed predictivity of chemically-induced
karyomegaly for renal carcinogenicity in both rats and mice. Examples of these misleading
situations are described and discussed.
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Affiliation(s)
- Gordon C Hard
- Private Toxicology Consultant, 203 Paku Drive, Tairua 3508, New Zealand
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Hard GC, Cohen SM, Ma J, Yu F, Arnold LL, Banton MI. Histopathology re-examination of the NTP toxicity/carcinogenicity studies of tert-butyl alcohol to identify renal tumor and toxicity modes of action. Regul Toxicol Pharmacol 2018; 102:65-73. [PMID: 30590081 DOI: 10.1016/j.yrtph.2018.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/07/2018] [Accepted: 12/15/2018] [Indexed: 11/18/2022]
Abstract
Tert-butyl alcohol (TBA) targets the rat kidney following repeated exposures, including renal tubule tumors. The mode of action (MOA) of these tumors, concluded by a pathology working group, involves both alpha2u-globulin nephropathy (α2u-gN) and exacerbated chronic progressive nephropathy (CPN), but has been disputed and an undefined MOA proposed. This study further reviews the histology slides of male and female rat kidneys from the NTP drinking water 13-week toxicity and 2-year carcinogenicity studies, including the 15-month interim sacrifice group. The papillary epithelial lining alteration formerly referred to as "transitional cell hyperplasia" develops as part of advanced CPN and does not represent a separate toxicity. No changes were observed in the kidney pelvis urothelium. The only alterations in subchronic male rats involved α2u-gN and CPN, without test article-related alterations in females. Focused examination of areas of parenchyma unaffected by CPN in TBA-treated male and female rats of the chronic studies revealed no renal tubule abnormalities other than from the effects of α2u-gN and CPN. Unrelated to toxicity were spontaneous amphophilic or vacuolar tubule proliferative lesions. All observed TBA-associated non-neoplastic and neoplastic histopathological changes in the kidney can be explained by α2u-gN or enhanced CPN, neither of which are relevant to humans.
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Affiliation(s)
| | - Samuel M Cohen
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198-3135, USA; Havlik-Wall Professor of Oncology, USA.
| | - Jihyun Ma
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198-4375, USA
| | - Fang Yu
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198-4375, USA
| | - Lora L Arnold
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, 68198-3135, USA
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Abstract
The important renal tumors that can be induced by exposure of rats to chemical carcinogens are renal tubule tumors (RTTs) derived from tubule epithelium; renal pelvic carcinoma derived from the urothelial lining of the pelvis; renal mesenchymal tumors (RMTs) derived from the interstitial connective tissue; and nephroblastoma derived from the metanephric primordia. However, almost all of our knowledge concerning mechanisms of renal carcinogenesis in the rodent pertains to the adenomas and carcinomas originating from renal tubule epithelium. Currently, nine mechanistic pathways can be identified in either the rat or mouse following chemical exposure. These include direct DNA reactivity, indirect DNA reactivity through free radical formation, multiphase bioactivation involving glutathione conjugation, mitotic disruption, sustained cell proliferation from direct cytotoxicity, sustained cell proliferation by disruption of a physiologic process (alpha 2u-globulin nephropathy), exaggerated pharmacologic response, species-dominant metabolic pathway, and chemical exacerbation of chronic progressive nephropathy. Spontaneous occurrence of RTTs in the rat will be included since one example is a confounder for interpreting kidney tumor results in chemical carcinogenicity studies in rats.
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Hall WC, Elder B, Walker CL, Cai SL, Peters DG, Goodman DG, Ulland BM, Borzelleca JF. Spontaneous Renal Tubular Hyperplastic and Neoplastic Lesions in Three Sprague-Dawley Rats from a 90-Day Toxicity Study. Toxicol Pathol 2016; 35:233-41. [PMID: 17366317 DOI: 10.1080/01926230601156252] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Multiple renal tubular cell adenomas and atypical tubular hyperplasia were diagnosed in 2 high-dose and 1 mid-dose female Sprague–Dawley (Crl:CD®(SD)IGS BR) rats from a 90-day toxicity study of an amino acid found in green tea. The tumors were bilateral multicentric adenomas accompanied by atypical foci of renal tubular hyperplasia in both kidneys of the 3 animals. Toxic tubular changes that typically accompany renal carcinogenesis were not seen in any of the other animals of the study, suggesting rather, an underlying germline mutation of a tumor suppressor gene in these three rats. The histological appearance of these tumors and short latency was reminiscent of the spontaneous lesions reported to arise in Sprague–Dawley rats in the Nihon rat model. Nihon rats develop kidney tumors as a result of a spontaneous mutation in the rat homologue of the Birt-Hogg-Dubé gene ( Bhd). Frozen samples of liver from two tumor-bearing rats were assayed for germline alterations in the Bhd gene. The entire coding region (exons 3–13) of the Bhd gene was sequenced, and a guanine (nt106G) to adenine (nt106A) polymorphism was detected resulting in a glycine to arginine (G36R) substitution in both tumor-bearing animals. In the study animals, the frequency of the A-allele (adenine) was determined to be 27% (19/70). Interestingly, rats obtained from two other sources (n = 17) only carried the nt106G-allele, consistent with the published rat sequence for this gene. Genetic fingerprinting of microsatellite loci indicated that the rats had a shared genetic background. Laser capture microdissection (LCM) of the tumor cells demonstrated a loss of heterozygosity in the Bhd gene in neoplastic cells of one of the two animals. Taken together, these data suggest that the tumors observed in these animals arose spontaneously as a result of a shared genetic susceptibility leading to the development of renal tubular neoplasms.
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Lanzoni A, Piaia A, Everitt J, Faustinelli I, Defazio R, Cavaliere L, Cristofori P. Early Onset of Spontaneous Renal Preneoplastic and Neoplastic Lesions in Young Conventional Rats in Toxicity Studies. Toxicol Pathol 2016; 35:589-93. [PMID: 17654399 DOI: 10.1080/01926230701383202] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Although occurring in aged laboratory rodents, spontaneous renal tumour are unknown in animals younger than 18 weeks. A survey on renal preneoplastic and neoplastic lesions has been performed on Sprague-Dawley rats from general toxicology studies over the period January 2004—May 2006. Data from 2249 rats necropsied and 1206 rats (688 males and 518 females) examined microscopically from 52 studies, are reported. The age range at necropsy was between 12 and 18 weeks and all the animals were obtained from the same supplier. Three cases of tubular carcinoma, 1 tubular adenoma, and 4 cases of atypical tubular hyperplasia were observed in 5 females and 3 males from both control and treated groups from 6 studies with unrelated test compounds. In treated rats, the lesions were considered spontaneous in nature, rather than related to treatment, because of: (1) their sporadic incidence, (2) the short duration of the studies, and (3) the absence of similar lesions in other rats given the same test compound. These lesions are considered a recently occurring spontaneous finding, and the similarities with the familial renal cancer models, namely the Eker and the Nihon models, strongly suggest genetic factors as responsible for the lesions.
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Affiliation(s)
- Anna Lanzoni
- Pathology Department, GlaxoSmithKline, Verona, Italy.
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Abstract
Renal tubule lesions often prove troublesome for toxicologic pathologists because of the diverse nature and interrelated cell types within the kidney and the presence of spontaneous lesions with overlapping morphologies similar to those induced by renal toxicants. Although there are a number of guidance documents available citing straightforward diagnostic criteria of tubule lesions for the pathologist to refer to, most are presented without further advice on the when to or to the why and the why not of diagnosing one lesion over another. Documents presenting diagnostic perspectives and recommendations derived from an author’s experience are limited since guidance documents are generally based on descriptive observations. In this Regulatory Forum opinion piece, the authors attempt to dispel confusing renal tubule lesion terminology in laboratory animal species by suggesting histological advice on the recognition and interpretation of these complex entities.
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Affiliation(s)
- John Curtis Seely
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA
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Hardisty JF, Banas DA, Gopinath C, Hall WC, Hard GC, Takahashi M. Spontaneous renal tumors in two rats from a thirteen week rodent feeding study with grain from molecular stacked trait lepidopteran and coleopteran resistant (DP-ØØ4114-3) maize. Food Chem Toxicol 2013; 53:428-31. [PMID: 23246460 DOI: 10.1016/j.fct.2012.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 12/04/2012] [Accepted: 12/04/2012] [Indexed: 11/18/2022]
Abstract
A thirteen week feeding study was conducted by feeding young adult male and female Sprague Dawley [Crl:CD®(SD)] rats diets containing grain from genetically modified (GM) DP-ØØ4114-3 maize that was either untreated (4114) or treated in the field with glufosinate ammonium (4114GLU). Control rats were fed diets containing the same concentration of near isogenic, non-GM maize grain (091) or one of three types of commercially available non-GM maize grain. At the end of the in-life phase, renal tubule tumors were reported in two male rats consuming diets containing 4114 maize grain. An expert panel of pathologists was convened as a Pathology Working Group (PWG) to review coded kidney histology sections from control (091) and treated (4114 and 4114GLU) male rats. The objectives were for the panel to characterize the histopathologic findings and to interpret their relationship to consumption of the indicated diet. The PWG concluded unanimously that the kidney tumors were characteristic of amphophilic-vacuolar (AV) tumors and AV atypical tubular hyperplasia which represent a distinctive phenotype that has been reported to occur sporadically in young Sprague Dawley Rats. The PWG determined that the neoplasms and atypical tubular hyperplasias were multicentric and bilateral which typifies tumors of familial origin. Degenerative/regenerative or cytotoxic changes consistent with nephrotoxicity leading to tumor induction were not observed in these rats and thus supports the conclusion that tumors were unrelated to consumption of the test diet. It was the unanimous opinion of the PWG that the proliferative renal tubule cell lesions were spontaneous and not related to consumption of diets containing 4114 maize grain.
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Affiliation(s)
- Jerry F Hardisty
- Experimental Pathology Laboratories, Inc., Research Triangle Park, NC 27709, United States.
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Kudo K, Hoshiya T, Nakazawa T, Saito T, Shimoyama N, Suzuki I, Tamura K, Seely JC. Spontaneous renal tumors suspected of being familial in sprague-dawley rats. J Toxicol Pathol 2013; 25:277-80. [PMID: 23345931 PMCID: PMC3517924 DOI: 10.1293/tox.25.277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 07/03/2012] [Indexed: 12/05/2022] Open
Abstract
Spontaneous renal tubule tumors (RTTs), with a distinctive morphological phenotype, were
present in three Sprague-Dawley rats, 1 male and 2 females, out a total of 120 animals of each
sex from untreated and placebo control groups in a 2-year carcinogenicity study. One female had
one carcinoma, adenoma and hyperplasia, and the other female had five adenomas and many
hyperplastic lesions; the male case had one carcinoma. From these cases, a biological continuum
of hyperplasia, adenoma and carcinoma could be recognized. The tumors were present in the renal
cortex and appeared as solid lobulated growths with occasional central necrosis. The lobules
were divided by a small amount of fibrovascular tissue. Occasionally the larger tumors
contained a cystic area. Tumor cells appeared distinctive and exhibited variable amounts of
eosinophilic/amphophilic and vacuolated cytoplasm. Nuclei were round to oval with a prominent
nucleolus. Mitotic figures were uncommon, and no distant metastasis was noted. The tumors were
seen as multiple and bilateral lesions in two animals and had no apparent relationship to
chronic progressive nephropathy (CPN). Foci of tubule hyperplasia were also noted to contain
the same type of cellular morphology. The morphological and biological features of these 3
cases resembled the amphophilic-vacuolar (AV) variant of RTT that has been posited to be of
familial origin. This is a report of spontaneous familial renal tumors in Sprague-Dawley rats
from Japan.
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Affiliation(s)
- Kayoko Kudo
- Pathology Division, Gotemba Laboratory, Bozo Research Center Inc., 1284 Kamado, Gotemba, Shizuoka 412-0039, Japan
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Crabbs TA, Frame SR, Laast VA, Patrick DJ, Thomas J, Zimmerman B, Hardisty JF. Occurrence of Spontaneous Amphophilic-Vacuolar Renal Tubule Tumors in Sprague-Dawley Rats from Subchronic Toxicity Studies. Toxicol Pathol 2012; 41:866-71. [DOI: 10.1177/0192623312467523] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The low background incidence of tumors in rodents from subchronic toxicity studies makes it difficult to assess their relevance, especially when present only in treated animals. This report investigates the occurrence of renal tubule tumors (RTTs), specifically the amphophilic-vacuolar (AV) phenotypic variant, in young Sprague-Dawley (SD) rats from a survey of laboratories conducting subchronic toxicity studies spanning a period of 10 years (2002–2012). This survey establishes a general profile of tumor occurrence; it does not estimate overall incidence or prevalence. AV tumors are spontaneous, nontreatment-related tumors of familial origin, and morphologically distinct from conventional RTTs induced by exposure to renal carcinogens. They are composed of distinct lobules of large, round to polyhedral cells with vacuolated amphophilic to eosinophilic cytoplasm and prominent nucleoli. Data from five collaborating laboratories, representing 37 qualifying studies, are presented. In total, 58 renal tubule neoplasms were recorded in this data set. The AV tumor variant was reported more commonly than the conventional RTT ( n = 45 and 13, respectively), and it was recorded in both experimental ( n = 32) and control ( n = 13) groups. AV tumors occurred more often in females ( n = 34) than in males ( n = 11); conventional RTTs were recorded more often in males ( n = 9) than in females ( n = 4). AV tumors often occurred in more than one rat within the same study (up to 7) and were documented to occur in rats as young as 7 to 10 weeks of age. Results from this survey indicate that AV tumors are being reported more commonly in recent years; the majority ( n = 33) were reported in studies commencing since 2009. In conclusion, this study reaffirms that AV tumors are spontaneous, nontreatment-related lesions, and suggests that they may be more common than conventional RTTs in young SD rats. The authors propose that AV tumors be recorded separately from conventional RTTs in order to clearly distinguish these two renal tubule neoplasms from one another and allow for appropriate interpretation of a compound’s potential carcinogenic effect in the kidney.
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Affiliation(s)
- Torrie A. Crabbs
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA
| | - Steve R. Frame
- DuPont Haskell Global Centers for Health and Environmental Sciences, Newark, Delaware, USA
| | | | | | | | | | - Jerry F. Hardisty
- Experimental Pathology Laboratories, Inc., Research Triangle Park, North Carolina, USA
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Hard GC, Seely JC, Kissling GE, Betz LJ. Spontaneous occurrence of a distinctive renal tubule tumor phenotype in rat carcinogenicity studies conducted by the national toxicology program. Toxicol Pathol 2008; 36:388-96. [PMID: 18441261 DOI: 10.1177/0192623308315829] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The Toxicology Data Management System (TDMS) of the National Toxicology Program, National Institutes of Environmental Health Sciences, National Institutes of Health, was surveyed for occurrence and distribution of a distinctive renal tubule tumor type in rats. The hallmark features of this tumor included eosinophilic/amphophilic staining, large finely granular cells, and numerous vacuoles and/or minilumens. It is referred to here as the amphophilic-vacuolar (AV) variant of renal tubule tumor. Of 154 studies in which renal tubule tumors had been recorded in the standard single sections of kidney in the TDMS, there were collectively 1012 rats with renal adenomas, carcinomas, or adenocarcinomas, and of these, 100 displayed the distinctive AV morphology, representing 74 studies involving mostly the F344 rat, but also the Sprague-Dawley and Wistar strains. The AV tumors (mainly adenomas but also some carcinomas) occurred usually as solitary lesions in the affected animals. However, they were multiple and bilateral in a few cases. They were equally distributed between the sexes, did not metastasize (at least to the lung), and were not associated with chronic progressive nephropathy. The distribution of this renal tumor type was random across studies and dose groups, underscoring the likelihood that it was of spontaneous origin and not chemically induced. Accordingly, it is suggested that this distinctive renal tumor phenotype be recorded as a separate category from conventional RTT when assessing the carcinogenic potential of a test compound.
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Hard GC, Seely JC, Betz LJ, Hayashi SM. Re-evaluation of the kidney tumors and renal histopathology occurring in a 2-year rat carcinogenicity bioassay of quercetin. Food Chem Toxicol 2007; 45:600-8. [PMID: 17156907 DOI: 10.1016/j.fct.2006.10.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 09/22/2006] [Accepted: 10/17/2006] [Indexed: 10/24/2022]
Abstract
Renal histopathology in the most recent 2-year carcinogenicity bioassay of quercetin, in Fischer 344 rats, was re-evaluated in an attempt to determine a mode of action underlying a small increase in renal tubule tumors reported in the males (). The re-evaluation confirmed the reported increase in renal tumors in mid- and high-dose males, including a single carcinoma in a high-dose male, as well as an exacerbation of spontaneous, chronic progressive nephropathy (CPN) in male rats only. The re-evaluation also showed that there were no cellular alterations in the kidney indicative of chemical toxicity at 6 months, 15 months, or 2 years. The evidence linked the occurrence of the predominant basophilic adenomas and foci of atypical tubule hyperplasia (ATH) with the exacerbation of CPN to advanced grades of severity, supporting a mode of action involving quercetin interaction with CPN. This mode of action represents a secondary mechanism for renal tumor development, with no relevance for extrapolation to humans. In addition, the single carcinoma present in the high-dose males, along with 4 other lesions ranging from ATH to adenoma in male and female groups, were considered to have a unique phenotype associated previously with neoplasms of spontaneous and familial origin.
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Affiliation(s)
- Gordon C Hard
- Private Consultant, 203 Paku Drive, Tairua 3508, New Zealand.
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Seely JC, Haseman JK, Nyska A, Wolf DC, Everitt JI, Hailey JR. The effect of chronic progressive nephropathy on the incidence of renal tubule cell neoplasms in control male F344 rats. Toxicol Pathol 2002; 30:681-6. [PMID: 12512869 DOI: 10.1080/01926230290166779] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chronic progressive nephropathy (CPN) is the most frequently diagnosed lesion in the rat kidney. It has many components including degeneration and regeneration of renal tubule (RT) epithelium, glomerular lesions and interstitial inflammation and fibrosis. The incidence and severity of CPN is strain, age, and sex dependent and may be altered by a number of factors including exposure to xenobiotics. In National Toxicology Program (NTP) 2-year bioassays, xenobiotic-associated increased severity (exacerbation) of CPN often occurs in association with a marginal increased incidence of renal tubule cell neoplasms (RTCN). The relationship between CPN and RTCN development has not been definitively determined. The present study evaluated the association between severity of CPN and the occurrence of RTCN in control male F344 rats. A slight but statistically significant increase in CPN severity was present in those animals with RTCN compared to aged-matched controls without RTCN. Although these data suggest there is a positive correlation between CPN and RTCN, cause and effect were not determined. This marginal association suggests that the number of RTCNs that may develop secondary to chemically exacerbated nephropathy would be few.
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Affiliation(s)
- John C Seely
- Experimental Pathology Laboratories, Inc, Research Triangle Park, North Carolina 27709, USA.
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Thurman JD, Greenman DL, Kodell RL, Turturro A. Oral squamous cell carcinoma in ad libitum-fed and food-restricted Brown-Norway rats. Toxicol Pathol 1997; 25:217-24. [PMID: 9125781 DOI: 10.1177/019262339702500212] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A high incidence of oral squamous cell carcinoma was present in male and female Brown-Norway rats fed ad libitum or food-restricted dietary formulations. One hundred eight-nine rats were examined from 4 dietary treatment groups: male ad libitum, male food-restricted, female ad libitum, and female food-restricted. The ad libitum treatment groups for both males and females had significantly more cases of oral squamous cell carcinoma than cohort food-restricted groups. In ad libitum rats, 10 of 47 (21%) males and 15 of 47 (32%) females had oral squamous cell carcinoma, whereas only 4 of 47 (9%) males and 5 of 48 (10%) females in the food-restricted groups were similarly affected. The food-restricted rats lived significantly longer than ad libitum cohorts, so the higher incidence of squamous cell carcinoma was not dependent on extended lifespans. In addition to the dietary influence, a significant difference in oral squamous cell carcinoma incidence occurred between various familial lines. Family lines having representatives in both ad libitum and food-restricted groups had lower oral squamous cell carcinoma incidences in the food-restricted group whether comparing affected litters or individuals. Results suggest that the incidence of oral squamous cell carcinoma in our colony of Brown-Norway rats can be influenced by both the dietary treatment group and genetic predilection within certain pedigrees.
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Affiliation(s)
- J D Thurman
- Pathology Associates, Inc., Jefferson, Arkansas 72079, USA
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Abstract
Much more could be written about the issues addressed here, as well as about issues that are not even mentioned. The goal was to present a brief overview of some of the techniques and issues in quantitative health risk assessment based upon animal data. Hopefully, this overview will provoke some attention to specific in risk assessment that require more research. Perhaps the bibliographic references given will lead to other papers.
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Affiliation(s)
- D W Gaylor
- National Center for Toxicological Research U.S. Food and Drug Administration, Jefferson, AR 72079, USA
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