Evidence of oncotic cell death and DNA fragmentation in human hypertrophic chondrocytes in chondro-osteophyte.
OBJECTIVE
To investigate the population and morphology of in situ terminal deoxynucleotidyle transferase (TdT)-mediated dUTP nick end-labeling (TUNEL) stain positive non-apoptotic chondrocytes in hypertrophic zone of human chondro-osteophytes.


METHODS
Chondro-osteophytes from osteoarthritic patients were obtained at joint replacement surgery. Apoptosis was verified by light microscopic examination of Safranin O stained sections and TUNEL stain. TUNEL staining was also performed on hydrophilic resin embedded semi-thin and ultra-thin sections combined with the treatment with streptavidin-gold conjugates, observed by light microscopy with silver enhancement technique (TUNEL-LM with SE) and transmission electron microscopy (TUNEL-TEM) respectively for the simultaneous evaluation of cellular structure and DNA fragmentation.


RESULTS
In paraffin embedded sections (N=18), 31.5+/-6.1% of cells in the hypertrophic zone were TUNEL positive, but only 3.8+/-1.2% cells in this zone showed apoptotic appearances with cell shrinkage and nuclear condensation. Both in TUNEL-TEM and TUNEL-LM with SE, gold particles, which indicate DNA fragmentation, were observed within the nucleus of morphologically apoptotic chondrocytes, as well as of disintegrated, swollen chondrocytes.


CONCLUSIONS
In human chondro-osteophytes, hypertrophic chondrocytes might die by oncotic cell death with DNA fragmentation, as well as apoptosis.
Doi
T
T
Department of Orthopaedic Surgery, Okayama University Medical School, Okayama, Japan.
Nishida
K
K
Matsuo
M
M
Yoshida
A
A
Murakami
T
T
Inoue
H
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D017209:Apoptosis; D019902:Chondrocytes / Q000473:pathology* / Q000648:ultrastructure; D053938:DNA Fragmentation; D005260:Female; D006801:Humans; D006984:Hypertrophy; D020287:In Situ Nick-End Labeling / Q000379:methods; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000473:pathology*; D012680:Sensitivity and Specificity