LOCALIZATION OF MESSENGER-RNA OF PROCOLLAGEN ALPHA-1 TYPE-I IN TORN SUPRASPINATUS TENDONS - IN-SITU HYBRIDIZATIONS USING DIGOXIGENIN-LABELED OLIGONUCLEOTIDE PROBE

A tendon is predominantly composed of collagen Type I. To determine th e synthesis of collagen Type I after a rotator cuff tear, an in situ h ybridization technique was applied to localize cells containing procol lagen alpha 1 Type I in the proximal stump of five torn supraspinatus tendons obtained during surgery. Specimens were fixed in 10% buffered formalin, embedded in paraffin, and sectioned at 6 mu m. A 22 mer olig onucleotide corresponding to a sequence coding a part of human procoll agen alpha 1 Type I messenger RNA (amarna) was used as a hybridization probe. The probe was 3'-end labeled with digoxigenin-11-dUTP, and the probe-mRNA hybrids were enzymatically visualized using conventional c hromogens for alkaline phosphatase, The procollagen alpha 1 type I mRN A was clearly observed in the cells near the margin of the tear. Howev er, they were not consistently found in the vicinity of the intratendi nous extension of the tear and in cells of the subacromial bursa. It i s concluded that this method should be used to study the characteristi cs of collagen synthesis in a torn rotator cuff tendon.