Prevention of cartilage degeneration and gait asymmetry by lubricin tribosupplementation in the rat following anterior cruciate ligament transection

Abstract

Objective To investigate whether cartilage degeneration is prevented or minimized in an anterior cruciate ligament (ACL) injury rat model following a single dose-escalated intra-articular injection of lubricin derived from human synoviocytes in culture (HSL). Methods Unilateral ACL transection (ACLT) of the right hindlimb was performed in Lewis rats (N = 56). Control animals underwent a capsulotomy alone leaving the ACL intact (N = 11). Intra-articular injections (50μl/injection) of PBS (N = 14) and HSL (N = 14; 1600μg/ml) were performed on day 7 post-surgery. Animals were euthanized on day 70 post-surgery. Histological specimens were immunoprobed for lubricin, and sulfated glycosaminoglycans. Urinary CTX-II (uCTX-II) levels were measured on day 35 and 70 post-surgery. Hindlimb maximum applied force was determined using a variable resistor walkway to monitor quadruped gait asymmetries. Results Increased immunostaining for lubricin in the superficial zone and on the surface of cartilage was observed in lubricin-treated and control animals but not the PBS-treated nor the untreated ACLT animals. On post-operative day 35 and 70, uCTXII levels of HSL-treated animals were lower than corresponding untreated and PBS-treated (p=0.005; p<0.001 respectively) animals. ACLT animals treated with HSL and control animals distributed their weight equally between hindlimbs compared to PBS treated or untreated animals (p<0.01). Conclusion A single intra-articular injection of concentrated lubricin, following ACLT, reduced collagen type II degradation and improved weight bearing in the affected joint. This study supports the practice of tribosupplementation with lubricin in retarding cartilage degeneration and possibly the development of post-traumatic OA.

Role of lubricin and boundary lubrication in the prevention of chondrocyte apoptosis

“…Lubricin levels in SF decrease after anterior cruciate ligament injury and can take up to a year to return to baseline values (40). Several studies have demonstrated a disease-modifying effect for the intraarticular injection of native or recombinantly expressed lubricin in rodent models of posttraumatic OA (28,29,41,42). Our data indicate that lubricin supplementation likely protects damaged joints by preserving boundary lubrication, thereby protecting articular chondrocytes from apoptosis caused by excessive deformation and shear stress.…”

“…The samples were inspected for blood contamination, and then centrifuged following aspiration at 12,000 × g at 4°C for 10 min, and the aliquot was removed and stored at −80°C until testing. Lyophilized HSL was obtained from SBH Sciences and has been characterized previously (41,42). This product was solubilized using distilled water to a concentration of 250 μg/ mL, which is the estimated lubricin concentration in SF (40).…”

Animal Models of Osteoarthritis: Challenges of Model Selection and Analysis

“…Static hind limb weight distribution has been reported in rat OA studies using an incapacitance meter to measure relative weight distribution between hind limbs with the rat in a reared position (45). Dynamic gait analysis adds to this information by measuring gait changes such as symmetry of weight bearing during ambulation (46) and range of motion alterations (47). There is currently no standard method of gait analysis for use in animal OA models.…”

“…There is currently no standard method of gait analysis for use in animal OA models. Published methods have included scoring based on apparent lameness (40), measurement of stride length and limb rotation from inked paw prints in rats (48), measurement of dynamic force application using a pressure-sensitive walkway (42,46), and fluoroscopic measurements of hind limb motion (47). In larger animals, gait and functionality measures such as kinematic marker analysis, ground reaction force measurements, and observational gait assessment have been applied to study OA-related changes for conditions including dog hip OA (49), lameness in horses (50), and postsurgical sheep knee OA (51).…”

Análise da estrutura e padrão de expressão de lubricina, SMAD2 fosforilada na cadeia de ligação e colágeno tipo I na cartilagem articular da mandíbula durante o envelhecimento

“…Em ratos, a transecção do LCA resulta em redução na expressão de lubricina na CA [114][115][116] , sendo que, a aplicação de exercício físico forçado, diminui ainda mais a expressão 114 . Nesses casos, a injeção de lubricina no joelho é capaz de aumentar a área de expressão de lubricina na CA 115 , de promover um efeito condroprotetor e de reduzir o processo degenerativo instalado pela transecção e exercício 114 .…”