The long-term effects of hyaluronan during development of osteoarthritis following partial meniscectomy in a rabbit model.
OBJECTIVE
The long-term effect of hyaluronan (HA) on meniscus remodeling and articular cartilage preservation was assessed during the development of osteoarthritis following partial meniscectomy in a rabbit model.


METHODS
Approximately 60% of the region of each medial meniscus of 20 rabbit knees was excised bilaterally. The left knee joint was treated with five weekly intraarticular injections of 0.3 ml of HA, beginning 1 week after surgery. The right control knee was injected with PBS on the same schedule. Six months after surgery, animals were killed and the medial menisci and tibial articular cartilage were evaluated morphologically, histologically and biochemically.


RESULTS
Meniscal regeneration was observed as newly synthesized translucent tissue, and image analysis revealed that the amount of this tissue was significantly greater in the HA-treated menisci than in the vehicle-treated menisci. Safranin-O staining and image analysis revealed the increased presence of glycosaminoglycans in the HA-treated menisci relative to vehicle-treated menisci while vascularity and biochemical parameters (hydration, total GAGs and reducible collagen crosslinks) were statistically similar in HA- and vehicle-treated menisci. Gross morphologic grading with India ink revealed a trend for less deterioration of tibial articular cartilage in the HA group (P=0.09) while Mankin's score of the HA-treated tibial articular cartilage was marginally lower than that of the vehicle group (P=0.06). Biochemical assessments showed a trend for higher total GAGs concentration in the HA-treated articular cartilage when compared to the vehicle treatment group (P=0.06).


CONCLUSIONS
The present study has demonstrated that following partial meniscectomy, treatment with hyaluronan can enhance meniscal regeneration and may inhibit articular cartilage degeneration as long as six months post surgery.
Kobayashi
K
K
Department of Orthopaedics, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093-0630, USA.
Amiel
M
M
Harwood
F L
FL
Healey
R M
RM
Sonoda
M
M
Moriya
H
H
Amiel
D
D
D000818:Animals; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D002358:Cartilage, Articular / Q000473:pathology; D004195:Disease Models, Animal; D006820:Hyaluronic Acid / Q000627:therapeutic use*; D008592:Menisci, Tibial / Q000473:pathology / Q000502:physiology / Q000601:surgery*; D010003:Osteoarthritis / Q000473:pathology / Q000517:prevention & control*; D011183:Postoperative Complications / Q000473:pathology / Q000517:prevention & control*; D011817:Rabbits; D012038:Regeneration
D018501:Antirheumatic Agents; D006820:Hyaluronic Acid