Rats play a crucial role in advancing scientific research and contributing to the understanding of various diseases. The striking structural similarity between the rat foot and the intricate anatomy of the human hand has drawn scientific interest to these animals. However, detailed morphometric and functional analyses of the adult Sprague–Dawley rat foot, including its dimensions, range of motion, and grip strength, remain limited in the literature. We aimed to examine the hind feet of 42 adult male Sprague–Dawley rats, each weighing 300–350 g. Using a multifaceted approach, we inspected hind paw morphology and performed descriptive statistical analyses of foot dimensions (a), measured unilateral hind foot grasping strength (b), assessed joint mobility (c), and examined the microscopic appearance of the hind foot third digit (d). One animal was additionally used to observe the hind limb skeletal architecture using microcomputed tomography. This study provides critical normative data regarding the structure and function of the hind foot in adult Sprague–Dawley rats, thereby facilitating future studies on musculoskeletal diseases.
ParkerCCChenHFlagelSB, et al. Rats are the smart choice: Rationale for a renewed focus on rats in behavioral genetics. Neuropharmacology2014; 76 Pt B: 250–258.
2.
EllenbroekBYounJ.Rodent models in neuroscience research: Is it a rat race?Dis Model Mech2016; 9: 1079–1087.
3.
DuderstadtELSamuelsonDJ.Rat Mammary carcinoma susceptibility 3 (Mcs3) pleiotropy, socioenvironmental interaction, and comparative genomics with orthologous human 15q25.1-25.2. G3 (Bethesda)2023; 13: jkac288.
4.
RussoJ.Significance of rat mammary tumors for human risk assessment. Toxicol Pathol2015; 43: 145–170.
5.
KangSHChoiMSKimHK, et al. Polydeoxyribonucleotide improves tendon healing following Achilles tendon injury in rats. J Orthop Res2018; 36: 1767–1776.
6.
AitmanTDhillonPGeurtsAM.A RATional choice for translational research?Dis Model Mech2016; 9: 1069–1072.
7.
SzpirerC.Rat models of human diseases and related phenotypes: A systematic inventory of the causative genes. J Biomed Sci2020; 27: 84.
8.
BrydaEC.The Mighty Mouse: The impact of rodents on advances in biomedical research. Mo Med2013; 110: 207–211.
9.
IshiyamaSKisselCGuoX, et al. A syngeneic orthotopic osteosarcoma Sprague Dawley rat model with amputation to control metastasis rate. J Vis Exp2021; 171. https://doi.org/10.3791/62139
10.
GranadosPineda JHaqueMZMaskeyD, et al. Abstract 045: High fat diet increases blood pressure in Sprague Dawley Rats and induces salt sensitive hypertension: Role of NKCC2 in the thick ascending limb (TAL). Hypertension2023; 80(Suppl 1): A045.
11.
KirişçiMGüneriBSeyithanoğluM, et al. The protective effects of lycopene on ischemia/reperfusion injury in rat hind limb muscle model. Ulus Travma Acil Cerrahi Derg2020; 26: 351–360.
12.
CeberMAkarIInceI, et al. The effect of Edaravone on lung injury after lower limb ischemia-reperfusion in a rat model: Biochemical and histopathological insights. Turk J Vasc Surg2023; 32: 166–173.
13.
SayourNVBrennerGBMakkosA, et al. Cardioprotective efficacy of limb remote ischaemic preconditioning in rats: Discrepancy between a meta-analysis and a three-centre in vivo study. Cardiovasc Res2023; 119: 1336–1351.
14.
MarquesCMeirelesMNorbertoS, et al. High-fat diet-induced obesity rat model: A comparison between Wistar and Sprague-Dawley rat. Adipocyte2016; 5: 11–21.
15.
WeberK.Differences in types and incidence of neoplasms in Wistar Han and Sprague-Dawley Rats. Toxicol Pathol2017; 45: 64–75.
16.
DengKSzczecinskiNSArnoldD, et al. Neuromechanical model of rat hindlimb walking with two-layer CPGs. Biomimetics (Basel)2019; 4: 21.
17.
JohnsonWLJindrichDLRoyRR, et al. A three-dimensional model of the rat hindlimb: Musculoskeletal geometry and muscle moment arms. J Biomech2008; 41: 610–619.
18.
MeijerHJMBaanGCHuijingPA.Myofascial force transmission is increasingly important at lower forces: Firing frequency-related length-force characteristics of rat extensor digitorum longus. Acta Physiol (Oxf)2006; 186: 185–195.
19.
HuijingPAMaasHBaanGC.Compartmental fasciotomy and isolating a muscle from neighboring muscles interfere with myofascial force transmission within the rat anterior crural compartment. J Morphol2003; 256: 306–321.
20.
McCombeDKubickiMWitschiC, et al. A collagen prolyl 4-hydroxylase inhibitor reduces adhesions after tendon injury. Clin Orthop Relat Res2006; 451: 251–256.
21.
MaynardRDownesN.Anatomy and histology of laboratory rat in toxicology and biomedical research. London: Academic Press, 2019, Chapters 4–6, pp.23–76.
22.
MescherA.Janqueira’s basic histology text and atlas. New York: McGraw Hill, 2024, Chapters 5–10, pp.96–214.
23.
KhayyeriHHammermanMTurunenMJ, et al. Diminishing effects of mechanical loading over time during rat Achilles tendon healing. PLoS One2020; 15: e0236681.
24.
JavidiMMcGowanCPSchieleNR, et al. Tendons from kangaroo rats are exceptionally strong and tough. Sci Rep2019; 9: 8196.
25.
BorrellJAFrostSBPetersonJ, et al. A 3D map of the hindlimb motor representation in the lumbar spinal cord in Sprague Dawley rats. J Neural Eng2017; 14: 016007.
26.
LittleDAmadioPCAwadHA, et al. Preclinical tendon and ligament models: Beyond the 3Rs (replacement, reduction, and refinement) to 5W1H (why, who, what, where, when, how). J Orthop Res2023; 41: 2133–2162.
27.
NicklasWBaneuxPBootR, et al. Recommendations for the health monitoring of rodent and rabbit colonies in breeding and experimental units. Lab Anim2002; 36: 20–42.
28.
MählerMBerardMFeinsteinR, et al. FELASA recommendations for the health monitoring of mouse, rat, hamster, guinea pig and rabbit colonies in breeding and experimental units. Lab Anim2014; 48: 178–192.
29.
IsvoranuGManoleENeaguM.Gait analysis using animal models of peripheral nerve and spinal cord injuries. Biomedicines2021; 9: 1050.
30.
BerrymannRNBandyWD.Joint range of motion and muscle length testing. 4th ed. St. Louis, MO: Elsevier, 2023, pp.16–17.
31.
WongJKFLuiYHKapaceeZ, et al. The cellular biology of flexor tendon adhesion formation: An old problem in a new paradigm. Am J Pathol2009; 175: 1938–1951.
32.
HorowitzGL.Defining, establishing, and verifying reference intervals in the clinical laboratory: approved guideline. Wayne, PA: Clinical and Laboratory Standards Institute, 2010, p.61.
NotermansTHammermanMEliassonP, et al. Tendon mechanobiology in small-animal experiments during post-transection healing. Eur Cell Mater2021; 42: 375–391.
35.
HartDAAhmedASChenJ, et al. Optimizing tendon repair and regeneration: How does the in vivo environment shape outcomes following rupture of a tendon such as the Achilles tendon?Front Bioeng Biotechnol2024; 12: 1357871.
36.
FreedmanBRSalkaNSMorrisTR, et al. Temporal healing of Achilles tendons after injury in rodents depends on surgical treatment and activity. J Am Acad Orthop Surg2017; 25: 635–647.
37.
BertelliJAMiraJC.The grasping test: A simple behavioral method for objective quantitative assessment of peripheral nerve regeneration in the rat. J Neurosci Methods1995; 58: 151–155.
38.
LauerHPrahmCThielJT, et al. The grasping test revisited: A systematic review of functional recovery in rat models of median nerve injury. Biomedicines2022; 10: 1878.
39.
NavarroX.Functional evaluation of peripheral nerve regeneration and target reinnervation in animal models: A critical overview. Eur J Neurosci2016; 43: 271–286.
40.
NavarroXUdinaE.Methods and protocols in peripheral nerve regeneration experimental research: Part III–electrophysiological evaluation. Int Rev Neurobiol2009; 87: 105–126.
41.
TimpaniCAKourakisSDebruinDA, et al. Dimethyl fumarate modulates the dystrophic disease program following short-term treatment. JCI Insight2023; 8: e165974.
42.
ZheleznovaNNSunCPatelN, et al. Comparison of different animal models in hindlimb functional recovery after acute limb ischemia-reperfusion injury. Biomedicines2024; 12: 2079.
43.
KuroiwaTAmadioPC.Flexor tendon adhesion formation: Current concepts. Hand Clin2023; 39: 171–180.
44.
BrowerMGraceMKotzCM, et al. Comparative analysis of growth characteristics of Sprague Dawley rats obtained from different sources. Lab Anim Res2015; 31: 166.
45.
WangQTimberlakeMAPrallK, et al. The recent progress in animal models of depression. Prog Neuropsychopharmacol Biol Psychiatry2017; 77: 99–109.
46.
MallonWJBrownHRNunleyJA.Digital ranges of motion: Normal values in young adults. J Hand Surg Am1991; 16: 882–887.
47.
AllenMJHankensonKDGoodrichL, et al. Ethical use of animal models in musculoskeletal research. J Orthop Res2017; 35: 740–751.
KhannaAFrielMGougouliasN, et al. Prevention of adhesions in surgery of the flexor tendons of the hand: What is the evidence?Br Med Bull2009; 90: 85–109.
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
