| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1995: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1994: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
On a hyphothesis that subacromial impingement would accelerate rotator cuff degeneration biochemically, nitric oxide (NO) of Achilles tendons of 7 young and elderly rats was evaluated under normal and hypo-circulation due to repeated compression. Oxygen tension (PO_2) and No of the supraspinatus tendon of 6 clinical impingement syndromes and 9 cadaver shoulders were measured at distal and proximal points of their anterior, middle and posterior portions using a digital PO_2 and NO monitor, as well as intratendinous blood flow with a laser-Doppler flowmetry. These values of clinical cases were examined in hanging, 90ﾟ abduction and re-resting postures of the humerus, and before and after an anterior acromioplasty during the operations, and those of cadavers were on and off compression of 133g/cm^2 by a F.P.meter.
Elderly rats had higher NO than younger ones, which would reflect aging of their tendons. However, the difference of NO between on normal and ischemic conditions was larger in younger group. This would suggest the greater potential of NO generation in younger rats. Blood flow of the operated tendon decreased by raising the arm up to 90ﾟ abduction and normalized by its re-resting. PO_2 did not change with the humeral abduction, but decreased after the arm was brought down. The low PO_2 (hypoxia) remained more than 30 mins. NO increased just after the arm was up to 90ﾟ abduction and was brought down. In cadaver tendons without circulation, PO_2 changed after removing the compression similarly to the living tendons, but NO could not be detected. This speculated the mechanism of hypoxia due to circulation of interstitial fluid. Although the mechanical impingement was suggested to be able to affect biochemical circumstances of the tendon, the correlation between PO_2, NO,and intratendinous circulation could not be clarified.Acromioplasty was effective to keep PO_2 normal, not NO.
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