Biomaterial Database

Scanning electron microscopic characterization of healing and normal rat ligament microstructure under slack and loaded conditions. 2003

Christof Hurschler, and Paolo P Provenzano, and Ray Vanderby

Department of Orthopedics and Rehabilitation, University of Wisconsin--Madison, Madison, Wisconsin 53792-3228, USA.

The objective of this study was to observe and compare behavior of the collagen fiber microstructure in normal and healing ligaments, both in situ and ex vivo, in order to add insight into the structure-function relationship in normal and healing ligaments. Fifty-two ligaments from 26 male rats were investigated. Eleven animals underwent surgical transection of both medial collateral ligaments (MCLs) (22 ligaments), which were allowed to heal for a period of 2 weeks. An additional 15 animals (30 ligaments) were used as normals. Ligaments were placed into six groups: Slack (n = 6 control, n = 6 healing), Reference (n = 4 control, n = 4 healing), Loaded (n = 4 control, n = 4 healing), 15 degrees Flexion (n = 4 control, n = 4 healing), 120 degrees Flexion (n = 4 control, n = 4 healing), and Tissue Strain vs. Flexion Angle (n = 8 normals). All ligaments, except those in the Tissue Strain vs. Flexion Angle group, were prepared for scanning electron microscopy. Tissues were harvested, mounted in a load frame, and chemically fixed in one of five states: (1). slack, (2). reference (onset of loading), (3). loaded, (4). 15 degrees knee flexion, or (5). 120 degrees knee flexion. After fixation the tissues were prepared for electron microscopy (SEM). The micrographs from the slack, reference, and loaded groups show fiber straightening with loading in normal ligaments as well as in both scar and "retracted" regions of healing ligaments. Collagen fibers' diameter and crimp patterns were dramatically changed in the scar region of healing ligaments: Width decreased from 19.4 +/- 1.7 microm to 6.5 +/- 2.1 microm (p <.000001), period from 51.4 +/- 15.1 microm to 11.0 +/- 2.4 microm (p <.000001), and amplitude from 9.8 +/- 0.8 microm to 3.9 +/- 0.8 microm (p <.000001). Normal ligaments fixed in situ show wavy regions at 120 degrees but less so at 15 degrees flexion. Healing ligaments fixed in situ show regions of fiber waviness in the scar region at 120 degrees and also at 15 degrees flexion, indicating ligament laxity persists toward both extremes of the range of motion. The data suggest that straightening of crimped fibers is a functionally relevant phenomenon, not only in normal but also in healing ligaments.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008855	Microscopy, Electron, Scanning	Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.	Scanning Electron Microscopy,Electron Scanning Microscopy,Electron Microscopies, Scanning,Electron Microscopy, Scanning,Electron Scanning Microscopies,Microscopies, Electron Scanning,Microscopies, Scanning Electron,Microscopy, Electron Scanning,Microscopy, Scanning Electron,Scanning Electron Microscopies,Scanning Microscopies, Electron,Scanning Microscopy, Electron
D003094	Collagen	A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).	Avicon,Avitene,Collagen Felt,Collagen Fleece,Collagenfleece,Collastat,Dermodress,Microfibril Collagen Hemostat,Pangen,Zyderm,alpha-Collagen,Collagen Hemostat, Microfibril,alpha Collagen
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013180	Sprains and Strains	A collective term for muscle and ligament injuries without dislocation or fracture. A sprain is a joint injury in which some of the fibers of a supporting ligament are ruptured but the continuity of the ligament remains intact. A strain is an overstretching or overexertion of some part of the musculature.	Sprains,Strains,Sprain,Strain,Strains and Sprains
D014945	Wound Healing	Restoration of integrity to traumatized tissue.	Healing, Wound,Healings, Wound,Wound Healings
D016474	Weight-Bearing	The physical state of supporting an applied load. This often refers to the weight-bearing bones or joints that support the body's weight, especially those in the spine, hip, knee, and foot.	Load-Bearing,Axial Loading,Loadbearing,Weightbearing,Axial Loadings,Load Bearing,Weight Bearing
D017207	Rats, Sprague-Dawley	A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.	Holtzman Rat,Rats, Holtzman,Sprague-Dawley Rat,Rats, Sprague Dawley,Holtzman Rats,Rat, Holtzman,Rat, Sprague-Dawley,Sprague Dawley Rat,Sprague Dawley Rats,Sprague-Dawley Rats
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus
D017885	Collateral Ligaments	A number of ligaments on either side of, and serving as a radius of movement of, a joint having a hingelike movement. They occur at the elbow, knee, wrist, metacarpo- and metatarsophalangeal, proximal interphalangeal, and distal interphalangeal joints of the hands and feet. (Stedman, 25th ed)	Lateral Ligaments,Ligaments, Collateral,Ligaments, Lateral,Collateral Ligament,Lateral Ligament,Ligament, Collateral,Ligament, Lateral