Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Lubricant's role in keeping joints limber comes into sharper focus

13.02.2007
Using a method that allows precise measurement of the biomechanical properties of the hip joints in mice, researchers at Duke University's Pratt School of Engineering have found new evidence that an ingredient of joint fluid called lubricin plays a significant role in keeping joints limber.

The researchers say the finding offers the strongest evidence yet that treatments designed to increase levels of lubricin in humans may help stall the deterioration of arthritic joints.

The team found that the arthritic joints of mice lacking the gene that controls the production of lubricin show greater friction than do joints in normal animals. When observed at the molecular level, the surface of the mutant animals' joint cartilage also appears rougher and less stiff -- a finding that the researchers said suggests a loss of the cartilage's mechanical integrity without lubricin.

"Lubricin has been considered important, but the experiments had not been done," said Stefan Zauscher, a professor of mechanical engineering and materials science at the Pratt School. "This is the first look at the effects on biomechanics of lubricin's presence or absence."

... more about:
»cartilage »lubricin »measurement »role

Team member Jeffrey Coles, a Ph.D. student working in Zauscher's laboratory, presented the findings on Monday, Feb. 12, at the annual meeting of the Orthopaedic Research Society, in San Diego. The work was supported by the National Institutes of Health.

While lubricin had been suspected to play a role in reducing joint friction, earlier studies had focused on another constituent of joint fluid called hyaluronic acid. Injections of this material are frequently used as a treatment for osteoarthritis, the most common form of arthritis. However, the treatment seems to work primarily as an anti-inflammatory agent, Zauscher noted, doing little to prevent further joint damage.

Last year, Zauscher's group reported evidence that lubricin acts as a repellant boundary layer between joint surfaces, reducing friction by preventing contacts altogether rather than simply "greasing the wheels" http://www.pratt.duke.edu/news/index.php?story=260.

Those results stemmed from the first examination of the changing molecular forces between a model joint and glass slide as the amount of lubricin in the solution between them increased.

Now, the researchers have applied a similar technique to the molecular-level study of mouse joints, comparing normal mice to those lacking the gene for lubricin. They used an atomic force microscope (AFM) to examine the cartilage found on the surface of the ball at the top of the thigh bone that fits into the hip socket of the mice.

AFM microscopes have a sharp tip that scans the surfaces of structures at the level of individual atoms and measures the force of molecular-level interactions. In this case, the team chemically modified the tip to imitate the chemical properties of joint cartilage.

The researchers used the modified tips to probe the surface of normal and lubricin-deficient joints, gaining measurements of the amount of friction between the two surfaces. They also obtained measurements of the roughness and stiffness of the cartilage surface.

When compared with mice that have normal joint cartilage, mice lacking lubricin showed two to three times the amount of friction and their joint surfaces were more than twice as rough. The stiffness of the joint cartilage in mutant mice also was reduced by a factor of five, the researchers found. They noted that these findings are consistent with the significant tissue degeneration in early osteoarthritis.

"It's clear from our findings that lubricin is important for protecting the structural integrity of joints," Coles said.

The researchers next will examine the effects of replacing lubricin on the joint surfaces of mutant mice. They are seeking a better understanding of how lubricin carries out its role as a boundary lubricant, leading perhaps to an improved treatment option for osteoarthritis. Preliminary evidence suggests that lubricin injections may prevent, or at least slow, further deterioration of joint cartilage in the arthritic mice.

Kendall Morgan | EurekAlert!
Further information:
http://www.duke.edu

Further reports about: cartilage lubricin measurement role

More articles from Life Sciences:

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

nachricht First transcription atlas of all wheat genes expands prospects for research and cultivation
17.08.2018 | Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

Im Focus: The “TRiC” to folding actin

Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.

Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Smallest transistor worldwide switches current with a single atom in solid electrolyte

17.08.2018 | Physics and Astronomy

Robots as Tools and Partners in Rehabilitation

17.08.2018 | Information Technology

Climate Impact Research in Hannover: Small Plants against Large Waves

17.08.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>