{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,2]],"date-time":"2026-01-02T19:38:48Z","timestamp":1767382728669,"version":"build-2065373602"},"reference-count":39,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,4,1]],"date-time":"2021-04-01T00:00:00Z","timestamp":1617235200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["This work is supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB\/04033\/2020","PhD grant 2020.04789.BD."],"award-info":[{"award-number":["This work is supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB\/04033\/2020","PhD grant 2020.04789.BD."]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>This study aimed to define appropriate humane endpoints (HEs) for an animal model of colorectal carcinogenesis (CRC). Twenty-nine male Wistar rats were divided into two control groups (CTRL1 and CTRL2) injected with ethylenediamine tetraacetic acid (EDTA)\u2013saline solutions and two induced groups (CRC1 and CRC2) injected with 1,2-dimethylhydrazine (DMH) for seven weeks. A score sheet with 14 biological parameters was used to assess animal welfare. Groups CRC1 and CTRL1 and groups CRC2 and CTRL2 were euthanized 11 and 17 weeks after the first DMH administration, respectively. Five animals from the induced groups died unexpectedly during the protocol (survival rates of 75.0% and 66.7% for groups CRC1 and CRC2, respectively). The final mean body weight (BW) was smaller in the CRC groups when compared with that in the CTRL groups. A uniformity of characteristics preceding the premature animals\u2019 death was observed, namely an increase of 10% in mean BW, swollen abdomen, diarrhea, and priapism. The surface abdominal temperature of group CRC2 was significantly higher, when compared with that of group CTRL2. The parameters already described in other cancer models proved to be insufficient. For the CRC model, we considered assessing the abdominal temperature, priapism, and sudden increase in the BW.<\/jats:p>","DOI":"10.3390\/ani11040985","type":"journal-article","created":{"date-parts":[[2021,4,1]],"date-time":"2021-04-01T07:23:17Z","timestamp":1617261797000},"page":"985","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Refinement of Animal Model of Colorectal Carcinogenesis through the Definition of Novel Humane Endpoints"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2463-5655","authenticated-orcid":false,"given":"Rita","family":"Silva-Reis","sequence":"first","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"given":"Ana I.","family":"Faustino-Rocha","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Department of Zootechnics, School of Sciences and Technology, University of \u00c9vora, 7000-812 \u00c9vora, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3111-4612","authenticated-orcid":false,"given":"Mariana","family":"Gon\u00e7alves","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8668-0638","authenticated-orcid":false,"given":"Catarina Castro","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6652-9770","authenticated-orcid":false,"given":"Tiago","family":"Ferreira","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"given":"Carla","family":"Ribeiro-Silva","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6573-7511","authenticated-orcid":false,"given":"Lio","family":"Gon\u00e7alves","sequence":"additional","affiliation":[{"name":"Engineering Department, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Institute for Systems and Computer Engineering, Technology and Science, 4200-465 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9757-6879","authenticated-orcid":false,"given":"Lu\u00eds","family":"Antunes","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"given":"Carlos","family":"Ven\u00e2ncio","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Department of Animal Sciences, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"given":"Rita","family":"Ferreira","sequence":"additional","affiliation":[{"name":"Associated Laboratory for Green Chemistry (REQUIMTE), Department of Chemistry, University of Aveiro (UA), 3810-193 Aveiro, Portugal"}]},{"given":"Adelina","family":"Gama","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Animal and Veterinary Research Center (CECAV), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9519-4044","authenticated-orcid":false,"given":"Paula A.","family":"Oliveira","sequence":"additional","affiliation":[{"name":"Center for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"},{"name":"Department of Animal Sciences, University of Tr\u00e1s-os-Montes and Alto Douro (UTAD), 5000-801 Vila Real, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Prasad, C.B. (2016). A Review on Drug Testing in Animals. Transl. Biomed., 7.","DOI":"10.21767\/2172-0479.100099"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"116","DOI":"10.1016\/j.lfs.2017.02.004","article-title":"Experimental mammary carcinogenesis\u2014Rat models","volume":"173","author":"Alvarado","year":"2017","journal-title":"Life Sci."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Hau, J. (2008). Animal Models for Human Diseases. Sourcebook of Models for Biomedical Research, Humana Press.","DOI":"10.1007\/978-1-59745-285-4_1"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"206","DOI":"10.1242\/dmm.002733","article-title":"Rats!","volume":"2","author":"Iannaccone","year":"2009","journal-title":"Dis. Model. Mech."},{"key":"ref_5","first-page":"1073","article-title":"Implementation of Human Endpoints in a Urinary Bladder Carcinogenesis Study in Rats","volume":"31","author":"Oliveira","year":"2017","journal-title":"In Vivo"},{"key":"ref_6","first-page":"120","article-title":"Russell and Burch\u2019s 3Rs then and now: The need for clarity in definition and purpose","volume":"54","author":"Tannenbaum","year":"2015","journal-title":"J. Am. Assoc. Lab. Anim. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Franco, N.H., Correia-Neves, M., and Olsson, I.A.S. (2012). How \u201chumane\u201d is your endpoint?-refining the science-driven approach for termination of animal studies of chronic infection. PLoS Pathog., 8.","DOI":"10.1371\/journal.ppat.1002399"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1093\/ilar.41.2.72","article-title":"Defining the moribund condition as an experimental endpoint for animal research","volume":"41","author":"Toth","year":"2000","journal-title":"ILAR J."},{"key":"ref_9","first-page":"643","article-title":"Studying humane endpoints in a rat model of mammary carcinogenesis","volume":"22","author":"Ginja","year":"2019","journal-title":"Iran. J. Basic Med. Sci."},{"key":"ref_10","unstructured":"Olfert, E., Bhasin, J., Latt, R., Macallum, E., McCutcheon, K., Rainnie, D., and Schunk, M. (1998). CCAC Guidelines on: Choosing an Appropriate Endpoint in Experiments Using Animals for Research, Teaching and Testing."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1093\/ilar.41.2.87","article-title":"Humane endpoints and cancer research","volume":"41","author":"Wallace","year":"2000","journal-title":"ILAR J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1555","DOI":"10.1038\/sj.bjc.6605642","article-title":"Guidelines for the welfare and use of animals in cancer research","volume":"102","author":"Workman","year":"2010","journal-title":"Br. J. Cancer"},{"key":"ref_13","first-page":"1","article-title":"Analysis of the intestinal lumen microbiota in an animal model of colorectal cancer","volume":"9","author":"Zhu","year":"2014","journal-title":"PLoS ONE"},{"key":"ref_14","unstructured":"Walker, H., Hall, W., and Hurst, J. (1990). Dyspnea, Orthopnea, and Paroxysmal Nocturnal Dyspnea. Clinical Methods: The History, Physical, and Laboratory Examinations, Butterworths."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"153","DOI":"10.1177\/026119290403201s25","article-title":"Non-invasively Assessing Disturbance and Stress in Laboratory Rats by Scoring Chromodacryorrhoea","volume":"32","author":"Mason","year":"2004","journal-title":"Altern. Lab. Anim."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1186\/1744-8069-7-55","article-title":"The Rat Grimace Scale: A Partially Automated Method for Quantifying Pain in the Laboratory Rat via Facial Expressions","volume":"7","author":"Sotocina","year":"2011","journal-title":"Mol. Pain"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1989","DOI":"10.1016\/j.fct.2011.05.010","article-title":"High doses of olive leaf extract induce liver changes in mice","volume":"49","author":"Henriques","year":"2011","journal-title":"Food Chem. Toxicol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1S","DOI":"10.1293\/tox.29.1S","article-title":"Nonproliferative and Proliferative Lesions ofthe Gastrointestinal Tract, Pancreas andSalivary Glands of the Rat and Mouse","volume":"29","author":"Nolte","year":"2016","journal-title":"J. Toxicol. Pathol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"683","DOI":"10.1136\/gutjnl-2015-310912","article-title":"Global patterns and trends in colorectal cancer incidence and mortality","volume":"66","author":"Arnold","year":"2017","journal-title":"Gut"},{"key":"ref_20","first-page":"19","article-title":"Navale Animal Models of Cancer: A Review","volume":"4","author":"Archana","year":"2013","journal-title":"Int. J. Pharm. Sci. Res."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1159\/000085342","article-title":"Mouse Models of Colorectal Cancer and Liver Metastases","volume":"22","author":"Heijstek","year":"2005","journal-title":"Dig Surg"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"430","DOI":"10.1016\/j.bbrc.2009.05.080","article-title":"Biochemical and Biophysical Research Communications Combination of aging and dimethylhydrazine treatment causes an increase in cancer\u2014stem cell population of rat colonic crypts","volume":"385","author":"Levi","year":"2009","journal-title":"Biochem. Biophys. Res. Commun."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1186\/s13099-015-0076-y","article-title":"Animal models to study acute and chronic intestinal inflammation in mammals","volume":"7","author":"Jiminez","year":"2015","journal-title":"Gut Pathog."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1038\/nrn.2015.8","article-title":"Neurobiology of rodent self-grooming and its value for translational neuroscience","volume":"17","author":"Kalueff","year":"2016","journal-title":"Nat. Rev. Neurosci."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"591","DOI":"10.1038\/nrn.2016.103","article-title":"\u201cStressing\u201d rodent self-grooming for neuroscience research","volume":"17","author":"Song","year":"2016","journal-title":"Nat. Rev. Neurosci."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Jirkof, P., Rudeck, J., and Lewejohann, L. (2019). Assessing Affective State in Laboratory Rodents to Promote Animal Welfare\u2014What Is the Progress in Applied Refinement Research?. Animals, 9.","DOI":"10.3390\/ani9121026"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"184","DOI":"10.1016\/j.mayocp.2019.02.021","article-title":"Screening for Colon Cancer in Older Adults: Risks, Benefits, and When to Stop","volume":"95","author":"Nee","year":"2020","journal-title":"Mayo Clin. Proc."},{"key":"ref_28","first-page":"234","article-title":"Endpoints for Mouse Abdominal Tumor Models: Refinement of Current Criteria","volume":"48","author":"Paster","year":"2009","journal-title":"Comp. Med."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"699","DOI":"10.3748\/wjg.v6.i5.699","article-title":"Chemoprevention of tea on colorectal cancer induced by dimethylhydrazine in Wistar rats","volume":"6","author":"Jia","year":"2000","journal-title":"World J. Gastroenterol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1160","DOI":"10.2164\/jandrol.112.016873","article-title":"Priapism as the initial manifestation of a penile and lower limb cutaneous metastasis of prostate adenocarcinoma with low serum PSA level","volume":"33","author":"He","year":"2012","journal-title":"J. Androl."},{"key":"ref_31","first-page":"21","article-title":"Effect of Intracorporeal Human Adipose\u2013Derived Stem Cells (hADSCs) on Corpora Cavernosa Transforming Growth Factor \u03b21 (TGF\u03b21) and Collagen Type I Concentration in Wistar Rat Priapism Model","volume":"12","author":"Siregar","year":"2020","journal-title":"Res. Rep. Urol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"501","DOI":"10.30802\/AALAS-CM-19-000002","article-title":"Influence of Pain and Analgesia on Cancer Research Studies","volume":"69","author":"Taylor","year":"2019","journal-title":"Comp. Med."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1177\/0023677217739934","article-title":"Analgesics promote welfare and sustain tumour growth in orthotopic 4T1 and B16 mouse cancer models","volume":"52","author":"Lofgren","year":"2018","journal-title":"Lab. Anim."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1210\/er.2009-0009","article-title":"The Effects of Opioids and Opioid Analogs on Animal and Human Endocrine Systems","volume":"31","author":"Vuong","year":"2010","journal-title":"Endocr. Rev."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"771","DOI":"10.1016\/j.biopha.2013.06.011","article-title":"Ultrasonographic, thermographic and histologic evaluation of MNU-induced mammary tumors in female Sprague-Dawley rats","volume":"67","author":"Silva","year":"2013","journal-title":"Biomed. Pharmacother."},{"key":"ref_36","first-page":"439","article-title":"Thermography in patients with inflammatory bowel disease and colorectal cancer: Evidence and review of the method","volume":"113","author":"Antonini","year":"2011","journal-title":"Period. Biol."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"428","DOI":"10.15761\/ICST.1000182","article-title":"Imaging in animal models","volume":"3","author":"Webb","year":"2016","journal-title":"Integr. Cancer Sci. Ther."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"950","DOI":"10.1136\/gut.2004.061283","article-title":"In vivo imaging of colitis and colon cancer development in mice using high resolution chromoendoscopy","volume":"54","author":"Becker","year":"2005","journal-title":"Gut"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"6100","DOI":"10.1038\/s41598-019-42230-w","article-title":"Magnetic Resonance Imaging and Bioluminescence Imaging for Evaluating Tumor Burden in Orthotopic Colon Cancer","volume":"9","author":"Ravoori","year":"2019","journal-title":"Sci. Rep."}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/11\/4\/985\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:25:44Z","timestamp":1760361944000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/11\/4\/985"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,4,1]]},"references-count":39,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2021,4]]}},"alternative-id":["ani11040985"],"URL":"https:\/\/doi.org\/10.3390\/ani11040985","relation":{},"ISSN":["2076-2615"],"issn-type":[{"type":"electronic","value":"2076-2615"}],"subject":[],"published":{"date-parts":[[2021,4,1]]}}}