|
| Experimental model | Anatomical site (defect dimension and experimental time) | Osteochondral treatment | Histological, histomorphometric, and biomechanical methods | Main outcomes | Author |
|
| Canine model |
| Twelve male dogs | Defects (11 mm Ø and 10 mm depth) in the load-bearing area of the femoral head for 3 and 6 months | Allogeneic BMSC-seeded DCM/DCBM scaffolds | (i) MicroCT on fresh samples: bone volume fraction
(ii) Indentation test on fresh samples: stiffness | Similar trend between microCT and biomechanics (stiffness) | Qiang et al. [43] |
|
| Eight mongrel dogs | Defects (3.5 and 4.5 mm Ø and 10 mm depth) in the medial femoral condyle for 12 months | Autograft and allograft plugs | (i) Paraffin embedding (sagittal cut)
(ii) Histological scoring system for proteoglycan content
(iii) H&E and Safranin O stainings;
(iv) MRI: MOCART score and T2 mapping
(v) Indentation test on fresh samples submerged in saline solution: second shear modulus | No statistical significance was seen in any parameter | McCarty et al. [44] |
|
| Twenty-seven TOYO beagles (15 months old) | Defects in the patellar groove (5.0 mm Ø and 2.0 mm depth) for 27 weeks | Ultrapurified alginate gel with or without microfractures | (i) Paraffin embedding (longitudinal cut)
(ii) Niederauer score
(iii) H&E and Safranin O stainings
(iv) IHC: Col I and II
(v) GAGs content
(vi) Changoor score for collagen orientation
(vii) MicroCT on frozen samples: volume of mineralized bone
(viii) Indentation test on fresh samples submerged in saline solution: stiffness | Similar trends between the histological and collagen orientation scores and biomechanical analysis of stiffness.
No differences in microCT | Baba et al. [45] |
|
| Twelve male dogs (2 year-old) | High load bearing surface of femoral condyles (4.2 mm Ø and 6 mm depth) for 3 and 6 months | Decellularized OC construct with or without 1 × 106 chondrogenically induced BMSCs | (i) Paraffin embedding
(ii) Solchaga score on paraffin-embedded samples (H&E and Toluidine Blue stainings); quantification of glycosaminoglycan content
(iii) MicroCT on fixed samples: BVF and BRP
(iv) Indentation test on samples fixed with cement and submerged in saline and EDTA solution: stiffness of cartilage and of subchondral bone (only at 6 months) | Significant on histological score and not in other parameters | Yang et al. [46] |
|
| Sixteen female mongrel dogs (2–5 years old) | Defects (8 mm Ø and 8 mm depth) in the weight-bearing areas of the lateral and medial femoral condyles for 6 months | Allograft plugs stored in different storage media and temperature | (i) Paraffin embedding
(ii) OARSI score
(iii) H&E, Toluidine Blue, and picrosirius red stainings
(iv) GAGs and collagen contents
(v) Indentation test on thawed samples: instantaneous tissue and dynamic modulus | Significance in histological score and not in biomechanics | Cook et al. [47] |
|
| Sixteen female mongrel dogs (2–5 years old) | Defects (8 mm Ø and 8 mm depth) in the weight-bearing areas of the lateral and medial femoral condyles for 6 months | Allograft plugs stored in different storage media and temperatures | (i) Paraffin embedding
(ii) OARSI score (at 1 week and 6 months)
(iii) H&E, Toluidine Blue, and picrosirius red stainings
(iv) Quantification of GAGs and collagen
(v) Indentation test on thawed samples: instantaneous tissue modulus and dynamic modulus (at 6 months) | No statistical significance was seen in any parameter | Cook et al. [48] |
|
| Swine model |
| Sixteen pigs (6 months old) | Defects (10 mm Ø, 4 mm depth) in the weight-bearing area of medial and lateral femoral condyles for 6 months | PGA/PLA scaffolds seeded with autologous BMSCs and cultivated in vitro for 2, 4, or 8 weeks | (i) Paraffin embedding (longitudinal cut)
(ii) Wakitani and Pineda scores
(iii) H&E, Safranin O, and sirius red staining
(iv) IHC: Col I, Col II, and osteocalcin
(v) Quantification of collagen and GAGa contents
(vi) Indentation test on fresh samples: compressive load-displacement curve and Young’s modulus | Similar trend between histological score and biomechanics | He et al. [49] |
|
| Yorkshire Duroc pigs (six months old) | Critical sized defects in the medial condyle and patellar groove (8 mm and 8 mm depth) for 6 months | Biphasic construct made of PCL for cartilage and PCL-TCP for bone with or without BMSCs | (i) Paraffin embedding (longitudinal cut)
(ii) O’Driscoll score
(iii) H&E, Toluidine blue/Safranin O, and Masson’s trichrome stainings
(iv) IHC: Col I and II
(v) MicroCT on fresh samples: degree of mineralization
(vi) Indentation test on thawed samples: Young’s modulus | Inferior healing in the patellar groove than in medial condyle; similar trends and positive correlation between microCT and biomechanical tests for all groups at both locations | Ho et al. [50] |
|
| Twelve male Gottingen minipigs (19.8-months old) | Critical sized defects in the medial and lateral trochlear facets (6 mm Ø and 8 mm depth) for 6 and 12 months | Autologous bone graft with or without autologous cartilage chips | (i) Resin embedding
(ii) ICRS II score
(iii) H&E staining
(iv) Quantification of hyaline tissue, fibrocartilage, fibrous tissue, bone, bone marrow and blood vessel area
(v) MicroCT on fresh samples: bone defect volume | Histomorphometric parameters showed differences between groups (articular cartilage, fibrocartilage, fibrous tissue, and ICRS II); microCT showed significant differences between experimental times but not between experimental groups | Christensen et al. [51] |
|
| Eight female Goettingen minipigs (1.5–2 years old) | Defects (5.4 mm Ø and 8 mm depth) in the trochlear groove for 2 months | Collagen type
I/III membrane with or without autologous BMSCs | (i) Paraffin embedding (longitudinal cut)
(ii) O’Driscoll score
(iii) Safranin O and col II stainings
(iv) IHC: Col II | Better significant results in the O’Driscoll score | Jung et al. [52] |
|
| Eighteen Göttingen minipig (1.5–2.5 years old) | Critical size defects (6.3 mm Ø and 10 mm depth) in the trochlear groove for 1.5, 3, and 13 months | Autologous osteoperiosteal bone plug with or without subperiosteal injection of a chondrogenic and osteogenic growth factor mixture | (i) Paraffin embedding (sagittal cut)
(ii) Safranin O staining
(iii) ICRS II score
(iv) Indentation test on fresh samples: compressive load-displacement curve | No statistical significance was seen in any parameter | Gotterbarm et al. [53] |
|
| Eighteen minipigs (7-8 months old) | Defects (7 mm Ø, 8 mm depth) in the medial femoral condyles for 6 months | PLGA scaffold with or without autologous chondrocytes or BMSCs | (i) Paraffin embedding (longitudinal cut)
(ii) ICRS score
(iii) H&E and Safranin O staining
(iv) MRI: MOCART score and biomechanical properties (collagen matrix and hydration)
(v) Indentation test on fresh samples: compressive modulus | Similar trend among histomorphometric, MRI scores (ICRS and MOCART), and biomechanics (compressive modulus) | Zuo et al. [54] |
|
| Equine model | | | | | |
| Five mature ponies | Defects (13 mm Ø and 7 mm depth) in femoral condyles with an inner hole (2.5 mm Ø and 10 mm depth) for 3, 6 (MRI and CT), and 13 months (microCT and histology) | Ad-BMP2 or Ad-BMP6 or Ad-GFP | (i) qMRI
(ii) CT in vivo and microCT ex vivo: lesion area and BMD for the lesion, drill, and adjacent subchondral bone
(iii) Paraffin embedding
(iv) O’Driscoll score
(v) H&E, Toluidine Blue and Safranin O stainings | Similar trends between MRI (T1 relaxation time) and clinical CT (BMD) at 12 weeks | Menendez et al. [55] |
|
| Ovine model |
| 16 adult female Dutch milk goats (4 years) | Defects (6 mm Ø and 6 mm depth) in each talus for 6 months | Demineralized bone matrix (DBM) with and without platelet-rich plasma (PRP) | (i) Paraffin embedding (longitudinal cut)
(ii) microCT: BV/TV
(iii) Goldner’s trichrome and Toluidine Blue stainings
(iv) Quantification of mineralized bone surface area and osteoid surface area (%), number of osteoclasts, osteoblasts, and osteocytes, MAR | No differences between groups | van Bergen et al. [56] |
|
| 8 skeletally mature female Dutch milk goats | Osteochondral defects (5 mm Ø, 3.5 mm depth) were created in medial condyles and trochlear grooves for 1 and 4 months | Acellular collagen I/III scaffolds or scaffolds seeded with SVF cells or cultured ASCs | (i) Indentation test (fresh sample): 50, 100, 200, and 300 μm indentation at a constant speed of 20 μm/sec with 4 mm Ø bold tip probe
(ii) Paraffin embedding (sagittal cut)
(iii) H&E and Alcian Blue stainings
(iv) IHC: COLLI, COLLII
(v) microCT
(vi) GAGs quantification | No significance in biomechanical test: better histological and immunohistochemical outcomes in acellular construct | Jurgens et al. [57] |
|
| Goat | Critical size defect 6 mm Ø × 6 mm depth in each medial femoral condyles for 6 and 12 months | (1) Maioregen scaffold
(2) Articular cartilage and growth plate ECM from porcine hind limbs AC-GP-ECM-derived bilayered scaffold | (i) MicroCT
(ii) Paraffin embedding (longitudinal cut)
(iii) H&E, Safranin O, and picrosirius red stainings
(iv) IHC: COLLII
(v) ICRS score | Hyaline-like repair tissue, better collage fiber organization of repaired tissue, and parallel fiber orientation with a lower range of dispersion in the superficial cartilage region | Cunniffe et al. [58] |
|
| 10 skeletally mature female Merino sheep (2–2.5 years) | Bilateral full thickness defects (4 mm Ø and 12 mm depth) created 2 mm below the calcified layer in the medial femoral condyles for 6 and 12 months | Triphasic implant engineered using β-tricalcium phosphate osseous phase and Coll I hydrogel chondral phase, with MSCs vs. autograft | (i) ICRS score
(ii) O’Driscoll score
(iii) Siebert semiquantitative score
(iv) Toluidine Blue and Levai-Laczko stainings
(v) Indentation test (maximum load 40 N) fresh sample
(vi) IHC: COLLII
(vii) MicroCT | No biomechanical differences between the groups | Marquass et al. [59] |
|
| 28 female Merino sheep (2–4 years old) | 7 mm Ø and 25 mm depth osteochondral defect in the centre of the load-bearing area of the medial femoral condyle for 1.5, 3, 6.5, and 13 months | Cylindrical plugs of microporous b-TCP (Ø: 7 mm; length: 25 mm; porosity: 43.5 ± 2.4%; pore Ø:∼5 μm) seeded with autologous chondrocytes cultured for 4 weeks | (i) Paraffin embedding (sagittal cut)
(ii) ICRS score
(iii) ESEM
(iv) TEM
(v) MicroCT
(vi) Masson’s trichrome, Safranin O, Giemsa, and TRAP stainings
(vii) O’Driscoll score
(viii) IHC: COLLI, COLLII, COLLX, and ALP
(ix) Quantification of mineralized bone substance and TCP proportion | Degradation of ceramic proportional to bone formation;
new cartilage formation and integration, although not with the same values of native one | Bernstein et al. [60] |
|
| 5 skeletally mature Arcott cross female sheep (2–4 years old) | Six 2 mm Ø, 2.5 to 8.5 mm deep Jamshidi biopsy holes were created bilaterally in the weight-bearing area of medial femoral condyle for 1 day, 3 weeks and 3 months | Presolidified chitosan-blood implant with fluorescent chitosan tracer | (i) Paraffin embedding (longitudinal cut)
(ii) MicroCT
(iii) Safranin O/fast green/iron hematoxylin, Gomori trichrome, and von Kossa/Toluidine Blue staining
(iv) IHC: COLLI, COLLII | Bone plate-induced chondroinduction is an articular cartilage repair mechanism; Jamshidi biopsy repair takes longer than 3 months and can be influenced by subchondral chitosan-blood implant | Bell et al. [61] |
|
| 24 adult goats (2–3 years old) | Osteochondral defect in the medial femoral condyles (6 mm Ø and 8 mm depth) for 3, 6, and 12 months | Multilayered scaffolds with oriented articular cartilage extracellular matrix- (ACEM-) derived cartilage layer, porous 3D printing (3DP) PLGA/TCP bone layer (BL), and an intermediate PLGA/TCP compact interfacial layer | (i) ICRS score
(ii) Safranin O and Toluidine Blue staining
(iii) O’Driscoll score
(iv) IHC: collII
(v) Compression test (initial load of 0.05 N, speed 0.01 mm/s) | MLS enhances hyaline-like tissue formation with better mechanical properties | Jia et al. S, 2018 [62] |
|
| 6 crossbred adult sheep | Critical size osteochondral defect (7 mm Ø, 5 mm depth) in the medial and lateral femoral condyles for 6 months | Biphasic HA-HYA alginate- based scaffold (bony layer 1.25% alginate and 4% HA; chondral layer 1% alginate and 0.5% HYA) | (i) Fortier-modified score
(ii) MicroCT: BV/TV; Tb.Sp.; Tb.Th.; and Tb.N.
(iii) Paraffin embedding (sagittal cut)
(iv) Safranin O/fast green staining
(v) Pineda score
(vi) IHC: COLLI, COLLII, VEGF | No differences were found between groups. | Filardo et al. [29] |
|
| 14 skeletally mature goat | Osteochondral defect (6 mm Ø, 8 mm depth) in the medial and lateral femoral condyles for 6 months | Biphasic osteochondral scaffold prepared using coralline aragonite with 1 to 2 mm depth drilled channels in the cartilage phase (+HA impregnation) or in the bone phase | (i) Fortier-modified score
(ii) ICRS score
(iii) paraffin embedding (longitudinal cut)
(iv) Safranin-HE, Masson trichrome, Safranin O/fast green stainings
(v) IHC: COLLI and COLLII
(vi) O’Driscoll score | Mechanical modification with drilled channels and impregnation of HA within the coral pores enhanced the scaffold’s cartilage regenerative potential | Kon et al. [63] |
|
| 12 skeletally matured female adult sheep | Osteochondral lesion (7 mm Ø, 9 mm thickness) in the right medial and lateral femoral condyles for 6 months | Osteochondral biomimetic scaffold with and without PRP | (i) Paraffin embedding (sagittal cut)
(ii) Safranin O/fast green staining
(iii) Niederauer score
(iv) IHC: COLLII | HA-coll scaffold promotes regeneration even without PRO | Kon et al. [64] |
|
| 22 Sardinian sheep (5.5 years old) | Bilateral osteochondral defects in medial and lateral condyles (6 mm Ø and 2 mm depth) involving subchondral bone for 1, 2, 6, 12, and 24 months | Embryonic stem-like (ESL) cells embedded in fibrin glue | (i) Indentation test (fresh samples)
(ii) H&E and Safranin O staining
(iii) Score by Kaplan
(iv) IHC: COLLII
(v) FISH | ESL cells enhance the regeneration of hyaline cartilage | Manunta et al. [65] |
|
| 24 skeletally mature female merino-mix sheep | 7.3 mm Ø defect and 12 mm in height in the central weight-bearing area of the femoral condyles for 3 and 6 months | Osteochondral autograft bottomed (recipient site depth 10 mm) and unbottomed (recipient site depth 12 mm) | (i) Paraffin embedding (sagittal cut)
(ii) Safranin O/von Kossa, Safranin O/fast green stainings, and TRAP staining | Full graft support improves long-term integration | Nosewicz et al. [66] |
|
| 12 female Merino sheep (2 years old) | Osteochondral defects in the weight-bearing area of femoral condyles (9.4 mm Ø and 1.1 cm depth) for 6 weeks | Biphasic scaffold of hydroxyapatite/collagen (scaffold a) and allogenous-sterilized bone/collagen (scaffold B) with or without chondroblasts | (i) ICRS score
(ii) Paraffin embedding (sagittal cut)
(iii) TRAP staining
(iv) H&E and Toluidine Blue stainings
(v) IHC: coll II and CD68
(vi) Gene expression: Col1A1, COLIIA1, SOX9, and CEP-68 | More immunocompetent cells around scaffold and a higher expression of COLLII and SOX9 for scaffold B | Schleicher et al. [67] |
|
| 28 female Merino sheep (2–4 years old) | Osteochondral defect of 7 mm Ø and 25 mm in height in the center femoral condyles for 1.5, 3, 6.5, and 13 months | Microporous beta TCP scaffold (7 mm Ø and 25 mm length) preseeded with autologous chondrocytes | (i) Indentation test in a special mount (3 mm Ø indenter, 200 μm penetration, maximal load 1.5 N): achieved load, absorbed energy, and contact stiffness
(ii) PMMA embedding (longitudinal cut)
(iii) ICRS score | Mechanical properties of TCP scaffold were similar to native cartilage
Lower score in the central area | Mayr et al. [68] |
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