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 Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>