title: Multiscale analysis of morphology and mechanics in tail tendon from the ZDSD rat model of type 2 diabetes.
abstract: Type 2 diabetes (T2D) impacts multiple organ systems including the circulatory, renal, nervous and musculoskeletal systems. In collagen-based tissues, one mechanism that may be responsible for detrimental mechanical impacts of T2D is the formation of advanced glycation end products (AGEs) leading to increased collagen stiffness and decreased toughness, resulting in brittle tissue behavior. The purpose of this study was to investigate tendon mechanical properties from normal and diabetic rats at two distinct length scales, testing the hypothesis that increased stiffness and strength and decreased toughness at the fiber level would be associated with alterations in nanoscale morphology and mechanics. Individual fascicles from female Zucker diabetic Sprague-Dawley (ZDSD) rats had no differences in fascicle-level mechanical properties but had increased material-level strength and stiffness versus control rats (CD). At the nanoscale, collagen fibril D-spacing was shifted towards higher spacing values in diabetic ZDSD fibrils. The distribution of nanoscale modulus values was also shifted to higher values. Material-level strength and stiffness from whole fiber tests were increased in ZDSD tails. Correlations between nanoscale and microscale properties indicate a direct positive relationship between the two length scales, most notably in the relationship between nanoscale and microscale modulus. These findings indicate that diabetes-induced changes in material strength and modulus were driven by alterations at the nanoscale.
authors.affiliation: Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, 723 W Michigan Street SL220D, Indianapolis, IN 46202, USA.
authors.forename: Armando Diaz
authors.initials: AD
authors.lastname: Gonzalez
authors.affiliation: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Maxime A
authors.initials: MA
authors.lastname: Gallant
authors.affiliation: Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, 723 W Michigan Street SL220D, Indianapolis, IN 46202, USA; Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: David B
authors.initials: DB
authors.lastname: Burr
authors.affiliation: Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis, 723 W Michigan Street SL220D, Indianapolis, IN 46202, USA; Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, USA. Electronic address: jmwalla@iupui.edu.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Wallace
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000502:physiology; D003094:Collagen / Q000737:chemistry / Q000502:physiology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D004195:Disease Models, Animal; D055119:Elastic Modulus / Q000502:physiology*; D005109:Extracellular Matrix / Q000737:chemistry / Q000502:physiology*; D005260:Female; D017127:Glycation End Products, Advanced / Q000502:physiology; D018625:Microscopy, Atomic Force; D051381:Rats; D017207:Rats, Sprague-Dawley; D011924:Rats, Zucker; D013623:Tail / Q000502:physiology; D013710:Tendons / Q000502:physiology*
chemical_list: D017127:Glycation End Products, Advanced; D003094:Collagen
keywords: AFM; Modulus; Nanoscale; Tension; Ultrastructure