Table 1.
Effects of Mechanical Stimulation on Superficial Zone Protein Expression in Articular Chondrocytes
| Load type | Study | Cells | Culture type | Loading regimen | Effects on SZP expression |
|---|---|---|---|---|---|
| Compression | Nugent et al.78 | 1- to 3-w/o bovine chondrocytes | Patellofemoral groove explants | 3–300 kPa, 0.01 Hz, for 24 h | Secretion into media increased 46%, 1 day after loading |
| Tension | Wong et al.82 | Calf (bovine) humeral head chondrocytes | Primary MZ/DZ cells in 2% alginate gel | 9% strain (0.004 MPa), 0.5 Hz, 3 h/day for 3 days | Gene expression increased 1.5-fold, 1 day after loading |
| Kamiya et al.116 | 6- to 8-m/o porcine chondrocytes | Confluent monolayer of mandibular condyle cells | 7% or 21% strain, 0.5 Hz, for 12, 24, or 48 h | 7% strain increased gene and protein expression; 21% strain decreased protein secretion | |
| Simple shear | Nugent et al.83 | 1- to 3-w/o bovine chondrocytes | Patellofemoral groove explants | 3% strain, 0.1 Hz (with 20% static compression) for 1 day | Secretion into media increased three- to fourfold during loading, 1 day and 2 days after loading |
| Sliding shear | Neu et al.61 | 3-m/o bovine chondrocytes | Femoral condyle explants | 0.5 mm/s, 0.1 MPa, for 5 min | Secretion into media increased two- to threefold, 2 days after loading |
| Hydrostatic pressure | Wong et al.82 | Calf (bovine) humeral head chondrocytes | Primary MZ/DZ cells in 2% alginate gel | 5 MPa, 0.5 Hz, 3 h/day for 3 days | No significant change in gene expression, 1 day after loading |
| Applied surface motion | Grad et al.100 | 3- to 4-m/o bovine chondrocytes | Metacarpal joint cells in porous polyurethane scaffold | Hip ball rotated 60° 0.6 Hz, applied 10%–20% comp. strain, for 1 h, 2x/day, for 3 days | Gene expression increased sevenfold, protein secretion detected and increased during loading cycle |
| Continuous passive motion | Nugent-Derfus et al.77 | 1- to 3-w/o bovine chondrocytes | Patellofemoral groove and femoral condyle explants | 10°–46° flexion, 110°/min (0.025 Hz), for 1 day | Increased % of PRG4 positive cells in regions subjected to continuous sliding, no significant differences in secretion |
y/o, year-old; m/o, month-old; w/o, week-old; MZ/DZ, middle zone/deep zone; 2x, twice; SZP, superficial zone protein.