Laser's effect on bone and cartilage change induced by joint immobilization: an experiment with animal model.
OBJECTIVE
Influence of low-level (810 nm, Ga-Al-As semiconductor) laser on bone and cartilage during joint immobilization was examined with rats' knee model.


METHODS
The hind limbs of 42 young Wistar rats were operated on in order to immobilize the knee joint. One week after operation they were assigned to three groups; irradiance 3.9 W/cm2, 5.8 W/cm2, and sham treatment. After 6 times of treatment for another 2 weeks both hind legs were prepared for 1) indentation of the articular surface of the knee (stiffness and loss tangent), and for 2) dual energy X-ray absorptiometry (bone mineral density) of the focused regions.


CONCLUSIONS
The indentation test revealed preservation of articular cartilage stiffness with 3.9 and 5.8 W/cm2 therapy. Soft laser treatment has a possibility for prevention of biomechanical changes by immobilization.
Akai
M
M
Department of Physical Therapy, Tsukuba College of Technology, Ibaraki, Japan. akai-reh@h.u-tokyo.ac.jp
Usuba
M
M
Maeshima
T
T
Shirasaki
Y
Y
Yasuoka
S
S
D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000528:radiation effects; D016723:Bone Remodeling / Q000528:radiation effects*; D002358:Cartilage, Articular / Q000503:physiopathology* / Q000528:radiation effects; D004195:Disease Models, Animal; D007103:Immobilization / Q000009:adverse effects*; D007596:Joints / Q000503:physiopathology* / Q000528:radiation effects; D053685:Laser Therapy; D007834:Lasers; D008297:Male; D011879:Radiotherapy Dosage; D051381:Rats; D017208:Rats, Wistar