Abstract
Background
Articular cartilage has limited intrinsic repair capacity, and osteochondral defects may progress to degenerative joint disease. Ozone has anti-inflammatory properties but is highly reactive and short-lived in gaseous form. This study evaluated whether a stabilized liquid ozone-containing formulation delivered through a hyaluronic acid/poly-D,L-lactide (HA/PDL) scaffold improves early histological repair of osteochondral defects.Methods
Forty female Sprague-Dawley rats were randomly allocated to four groups (n = 10 each): healthy reference, untreated defect, HA/PDL scaffold, and HA/PDL scaffold impregnated with the stabilized liquid ozone-containing formulation. A 1-mm-diameter, 3-mm-deep osteochondral defect was created in the right femoral intercondylar region. Animals were euthanized on postoperative day 45. Histological repair was evaluated using the Modified Mankin score (0-14), and residual cartilage damage area was quantified in mm² on the index haematoxylin and eosin (H&E)-stained section using calibrated ImageJ analysis.Results
All animals completed the study. Because the healthy reference group received zero scores for all histological variables, inferential analyses were restricted to the operated groups. Total Modified Mankin scores differed significantly among groups (p = 0.001), with the ozone-loaded scaffold group demonstrating lower scores than both the untreated defect group (p = 0.002) and the scaffold-only group (p = 0.006), whereas no difference was observed between the latter two groups (p = 1.000). Significant group differences were also observed for structure (p = 0.001) and tidemark integrity (p = 0.004). Residual cartilage damage area differed among the operated groups (p = 0.001) and was smaller in the ozone-loaded scaffold group than in the untreated defect group (p Conclusions
The stabilized liquid ozone-containing formulation delivered through an HA/PDL scaffold was associated with improved early histological repair compared with untreated defects and yielded lower histological degeneration scores than scaffold implantation alone. Because the formulation comprised multiple components and no ozone-free vehicle control was included, these findings cannot be attributed specifically to ozone and should be interpreted as evidence of improved early histological repair rather than true cartilage regeneration.Level of evidence
Not applicable (Experimental animal study).