Expression of interleukin-1beta, cyclooxygenase-2, and prostaglandin E2 in a rotator cuff tear in rabbits.
We investigated the specific factors related to shoulder pain due to a rotator cuff tear using a model in rabbits. A rotator cuff tear was surgically created, and the expression of interleukin-1beta (IL-1beta), prostaglandin E2 (PGE2), and cyclooxygenase-2 (COX-2) was analyzed. In the supernatant of the tissue culture of the torn tendon, IL-1beta production was detected. The amount of IL-1beta was highest 1 day after injury, and then decreased gradually to 21 days. PGE2, the mediator of pain and the product of COX-2, was also detected in the supernatant of the tissue culture. The production of PGE2 significantly increased to 7 days after injury, and then decreased to 21 days. RT-PCR analysis confirmed the mRNA expression of IL-1beta and COX-2 in the torn tendon. Immunohistochemical study demonstrated that cells in the tendon stump were immunopositive for IL-1beta and COX-2. Furthermore, in the affected joint, articular chondrocytes in the remote area from the tear expressed COX-2 strongly. When the rotator cuff is torn, IL-1beta is produced in the torn tendon, and stimulates the expression of COX-2 in not only the torn tendon but also in articular chondrocytes. The COX-2 then produces PGE2, which would mediate shoulder pain.
Koshima
Hiroshi
H
Department of Orthopaedic Surgery, Nagoya University School of Medicine, Nagoya, 466-8550 Japan.
Kondo
Seiji
S
Mishima
Shinji
S
Choi
Ho-Rim
HR
Shimpo
Hisashi
H
Sakai
Tadahiro
T
Ishiguro
Naoki
N
D000818:Animals; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D015232:Dinoprostone / Q000096:biosynthesis*; D004195:Disease Models, Animal; D007150:Immunohistochemistry; D053583:Interleukin-1beta / Q000096:biosynthesis*; D008297:Male; D011817:Rabbits; D017006:Rotator Cuff / Q000378:metabolism*; D000070636:Rotator Cuff Injuries; D020069:Shoulder Pain / Q000503:physiopathology
D053583:Interleukin-1beta; D051546:Cyclooxygenase 2; D015232:Dinoprostone