Licofelone (ML-3000), a dual inhibitor of 5-lipoxygenase and cyclooxygenase, reduces the level of cartilage chondrocyte death in vivo in experimental dog osteoarthritis: inhibition of pro-apoptotic factors.
OBJECTIVE
To evaluate in vivo therapeutic efficacy of licofelone, a novel competitive dual inhibitor of 5-lipoxygenase (5-LOX) and cyclooxygenase (COX) in chondrocyte death in the canine ligament transection model of osteoarthritis (OA), and to explore its effect on factors involved in the apoptotic phenomenon, i.e., caspase-3, COX-2, and inducible nitric oxide synthase (iNOS).


METHODS
Cartilage specimens were obtained from 3 experimental groups of dogs: Group 1, dogs subjected to sectioning of the anterior cruciate ligament of the right knee and given placebo treatment; Groups 2 and 3, operated dogs that received oral treatment with licofelone (2.5 or 5.0 mg/kg/day, respectively) for 8 weeks starting immediately after surgery. All dogs were killed 8 weeks postsurgery. The cartilage level of chondrocyte death was detected by TUNEL reaction. Cartilage distribution of caspase-3, COX-2, and iNOS was documented by immunohistochemistry using specific antibodies, and other levels were quantified by morphometric analysis.


RESULTS
In cartilage specimens from placebo treated dogs a large number of chondrocytes in the superficial layers stained positive for TUNEL reaction. Treatment with therapeutic concentrations of licofelone (2.5 and 5.0 mg/kg/day) markedly reduced the level of chondrocyte apoptosis to the same extent in both therapeutic groups (p < 0.0001, p < 0.002, respectively). In these groups, the levels of caspase-3, COX-2, and iNOS in cartilage from both condyles and plateaus were also significantly decreased (p < 0.0001, p < 0.0001, p < 0.0002, respectively) compared to the control (placebo) group.


CONCLUSIONS
Licofelone is an effective treatment in vivo, capable of reducing the level of OA chondrocyte death. This effect is likely mediated by a decrease in the level of caspase-3 activity, which may be related to the reduced production of 2 major factors involved in chondrocyte apoptosis, NO and prostaglandin E2. These findings may explain some of the mechanisms by which licofelone reduces the progression of experimental OA.
Boileau
Christelle
C
Osteoarthritis Research Unit, Hĵpital Notre Dame, Centre hospitalier de l'Université de Montréal, Québec, Canada.
Martel-Pelletier
Johanne
J
Jouzeau
Jean-Yves
JY
Netter
Patrick
P
Moldovan
Florina
F
Laufer
Stefan
S
Tries
Susanne
S
Pelletier
Jean-Pierre
JP
D000085:Acetates / Q000494:pharmacology*; D000284:Administration, Oral; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects*; D019902:Chondrocytes / Q000187:drug effects / Q000502:physiology*; D004195:Disease Models, Animal; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000032:analysis; D020781:Matrix Metalloproteinase 1 / Q000032:analysis; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism; D010003:Osteoarthritis / Q000188:drug therapy* / Q000473:pathology*; D011336:Probability; D011758:Pyrroles / Q000494:pharmacology*; D012016:Reference Values; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
D000085:Acetates; D007375:Interleukin-1; D011758:Pyrroles; D019001:Nitric Oxide Synthase; D020781:Matrix Metalloproteinase 1; C088092:licofelone