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.
Osteoarthritis Research Unit, Hĵpital Notre Dame, Centre hospitalier de l'Université de Montréal, Québec, Canada.
Christelle
C
Boileau
Johanne
J
Martel-Pelletier
Jean-Yves
JY
Jouzeau
Patrick
P
Netter
Florina
F
Moldovan
Stefan
S
Laufer
Susanne
S
Tries
Jean-Pierre
JP
Pelletier
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