Histomorphometric and biochemical effect of various hyaluronans on early osteoarthritis.
OBJECTIVE
To evaluate, histomorphometrically and biochemically, different protective effects of clinically used hyaluronans (HA).


METHODS
An experimental osteoarthritis (OA) model was applied to 132 mature NZW rabbits by resecting the unilateral anterior cruciate ligament (ACL). The other knee, where ACL remained intact, served as the control. We used native HA with different molecular weights, HA-50 (MW 5-7.3 x 10(5)), HA-80 (MW 8 x 10(5)), HA-360 (MW 3.6 x 10(6)), and crosslinked HA (HA-CL). HA were injected into the joint once a week for 5 weeks (HA-50, HA-80, HA-360) or 3 weeks (HA-CL) beginning 4 weeks after ACL transection. Histomorphometric and biochemical assessment was performed 9 weeks post-transection for both the HA treated and nontreated groups.


RESULTS
In gross morphological observation, cartilage degeneration was suppressed in HA treated groups, and this effect was superior in the groups receiving either HA-80 or HA-CL. Histomorphometric and biochemical analyses of the articular cartilage revealed similar results: the HA-80 and HA-CL groups showed no significant differences between the ACL transection and the control knees by histomorphometric variables, while the nontreated groups revealed significant degeneration. These evaluations were done in unblinded fashion. Biochemical analyses, including DNA synthesis in the synovium, also showed that articular cartilage and synovium in the HA-80 and HA-CL groups did not present significant changes compared to controls.


CONCLUSIONS
In quantitative evaluation of this short term study using the OA model, native HA-80 and HA-CL presented a superior cartilage protective effect compared to the other native HA.
Shimizu
C
C
Department of Orthopaedics, Kyoto Prefectural University of Medicine, Japan.
Kubo
T
T
Hirasawa
Y
Y
Coutts
R D
RD
Amiel
D
D
D000818:Animals; D002358:Cartilage, Articular / Q000033:anatomy & histology / Q000187:drug effects* / Q000378:metabolism; D004396:Coloring Agents / Q000494:pharmacology; D006820:Hyaluronic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D020370:Osteoarthritis, Knee / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010619:Phenazines / Q000494:pharmacology; D011817:Rabbits; D013583:Synovial Membrane / Q000187:drug effects / Q000473:pathology
D004396:Coloring Agents; D010619:Phenazines; D006820:Hyaluronic Acid; C009195:safranine T