This study provides a direct evidence of the role of mTOR and its downstream modulation of autophagy in articular cartilage homeostasis.

ObjectivesWe have previously shown that peroxisome proliferator-activated receptor gamma (PPARγ), a transcription factor, is essential for the normal growth and development of cartilage. In the present study, we created inducible cartilage-specific PPARγ knockout (KO) mice and subjected these mice to the destabilisation of medial meniscus (DMM) model of osteoarthritis (OA) to elucidate the specific in vivo role of PPARγ in OA pathophysiology. We further investigated the downstream PPARγ signalling pathway responsible for maintaining cartilage homeostasis.MethodsInducible cartilage-specific PPARγ KO mice were generated and subjected to DMM model of OA. We also created inducible cartilage-specific PPARγ/mammalian target for rapamycin (mTOR) double KO mice to dissect the PPARγ signalling pathway in OA.ResultsCompared with control mice, PPARγ KO mice exhibit accelerated OA phenotype with increased cartilage degradation, chondrocyte apoptosis, and the overproduction of OA inflammatory/catabolic factors associated with the increased expression of mTOR and the suppression of key autophagy markers. In vitro rescue experiments using PPARγ expression vector reduced mTOR expression, increased expression of autophagy markers and reduced the expression of OA inflammatory/catabolic factors, thus reversing the phenotype of PPARγ KO mice chondrocytes. To dissect the in vivo role of mTOR pathway in PPARγ signalling, we created and subjected PPARγ-mTOR double KO mice to the OA model to see if the genetic deletion of mTOR in PPARγ KO mice (double KO) can rescue the accelerated OA phenotype observed in PPARγ KO mice. Indeed, PPARγ-mTOR double KO mice exhibit significant protection/reversal from OA phenotype.SignificancePPARγ maintains articular cartilage homeostasis, in part, by regulating mTOR pathway.

ARC and CB were both effective for attenuation of CEHPSS, resulting in good to excellent outcomes with low morbidity and mortality. Residual shunting was suspected in a higher proportion of dogs treated with CB on the basis of abdominal ultrasonography results. However, further prospective randomized studies must be conducted with validated evaluation methods to verify this assumption.

Five modifications of a cricoarytenoid lateralization and two modifications of a thyroarytenoid lateralization laryngoplasty technique were evaluated for their effect on rima glottidis area. All procedures and evaluations were performed on canine cadaver larynges. Cricoarytenoid lateralization (CAL) techniques provided a greater increase of the size of the glottic opening than did any of the thyroarytenoid lateralization techniques. Cricoarytenoid and interarytenoid disarticulation associated with CAL did not significantly increase glottic size compared with normal. After disarticulation of the cricoarytenoid joint, there was no difference in glottic enlargement whether the suture was placed through the muscular process or through the articular facet of the arytenoid cartilage. Transection of the sesamoid band combined with cricoarytenoid diarticulation distorted the dorsal margin of the rima glottidis.

IntroductionThe aim of this prospective, randomized, controlled, double-blind study was to evaluate the effects of tiludronate (TLN), a bisphosphonate, on structural, biochemical and molecular changes and function in an experimental dog model of osteoarthritis (OA).MethodsBaseline values were established the week preceding surgical transection of the right cranial/anterior cruciate ligament, with eight dogs serving as OA placebo controls and eight others receiving four TLN injections (2 mg/kg subcutaneously) at two-week intervals starting the day of surgery for eight weeks. At baseline, Week 4 and Week 8, the functional outcome was evaluated using kinetic gait analysis, telemetered locomotor actimetry and video-automated behaviour capture. Pain impairment was assessed using a composite numerical rating scale (NRS), a visual analog scale, and electrodermal activity (EDA). At necropsy (Week 8), macroscopic and histomorphological analyses of synovium, cartilage and subchondral bone of the femoral condyles and tibial plateaus were assessed. Immunohistochemistry of cartilage (matrix metalloproteinase (MMP)-1, MMP-13, and a disintegrin and metalloproteinase domain with thrombospondin motifs (ADAMTS5)) and subchondral bone (cathepsin K) was performed. Synovial fluid was analyzed for inflammatory (PGE2 and nitrite/nitrate levels) biomarkers. Statistical analyses (mixed and generalized linear models) were performed with an α-threshold of 0.05.ResultsA better functional outcome was observed in TLN dogs than OA placebo controls. Hence, TLN dogs had lower gait disability (P = 0.04 at Week 8) and NRS score (P = 0.03, group effect), and demonstrated behaviours of painless condition with the video-capture (P < 0.04). Dogs treated with TLN demonstrated a trend toward improved actimetry and less pain according to EDA. Macroscopically, both groups had similar level of morphometric lesions, TLN-treated dogs having less joint effusion (P = 0.01), reduced synovial fluid levels of PGE2 (P = 0.02), nitrites/nitrates (P = 0.01), lower synovitis score (P < 0.01) and a greater subchondral bone surface (P < 0.01). Immunohistochemical staining revealed lower levels in TLN-treated dogs of MMP-13 (P = 0.02), ADAMTS5 (P = 0.02) in cartilage and cathepsin K (P = 0.02) in subchondral bone.ConclusionTiludronate treatment demonstrated a positive effect on gait disability and joint symptoms. This is likely related to the positive influence of the treatment at improving some OA structural changes and reducing the synthesis of catabolic and inflammatory mediators.

To evaluate the effect of licofelone, an arachidonic acid substrate with combined inhibitory activity against 5-lipoxygenase and cyclooxygenases 1 and 2, a double-blind, randomised and placebo-controlled study was conducted in 33 client-owned dogs that were lame owing to hindlimb osteoarthritis. Seventeen of the dogs received a placebo and 16 were treated with 2.5 mg/kg licofelone twice a day for 28 days. The dogs' lameness was assessed on a visual analogue scale (vas), and by force plate analyses at baseline and 14 and 28 days after starting the treatment. After 14 days the mean (se) change in peak vertical force in the licofelone-treated dogs (1.7 [0.8] per cent bodyweight) was significantly greater (P<0.05) than in the placebo-treated dogs (-0.3 [0.6] per cent bodyweight), and after 28 days the difference had increased. In contrast, the dogs' lameness, as assessed by the vas values, had decreased significantly over baseline in both the treated and control groups.

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Protandim and 6-gingerol, two potent nutraceuticals, have been shown to decrease free radicals production through enhancing endogenous antioxidant enzymes. In this study, we evaluated the effects of these products on the expression of different factors involved in osteoarthritis (OA) process. Human OA chondrocytes were treated with 1 ng/ml IL-1β in the presence or absence of protandim (0-10 μg/ml) or 6-gingerol (0-10 μM). OA was induced surgically in mice by destabilization of the medial meniscus (DMM). The animals were treated weekly with an intraarticular injection of 10 μl of vehicle or protandim (10 μg/ml) for 8 weeks. Sham-operated mice served as controls. In vitro, we demonstrated that protandim and 6-gingerol preserve cell viability and mitochondrial metabolism and prevented 4-hydroxynonenal (HNE)-induced cell mortality. They activated Nrf2 transcription factor, abolished IL-1β-induced NO, PGE , MMP-13, and HNE production as well as IL-β-induced GSTA4-4 down-regulation. Nrf2 overexpression reduced IL-1β-induced HNE and MMP-13 as well as IL-1β-induced GSTA4-4 down-regulation. Nrf2 knockdown following siRNA transfection abolished protandim protection against oxidative stress and catabolism. The activation of MAPK and NF-κB by IL-1β was not affected by 6-gingerol. In vivo, we observed that Nrf2 and GSTA4-4 expression was significantly lower in OA cartilage from humans and mice compared to normal controls. Interestingly, protandim administration reduced OA score in DMM mice. Altogether, our data indicate that protandim and 6-gingerol are essential in preserving cartilage and abolishing a number of factors known to be involved in OA pathogenesis. J. Cell. Biochem. 118: 1003-1013, 2017. © 2016 Wiley Periodicals, Inc.