Table 3.

Summary of Some Representative Studies Using Compressive Loads on Hyaline Cartilage.

Study Model	Chondrocytes Isolation Source	Load Magnitude	Frequency (Hz)	Application Scheme	Stimulation Time	Results	Reference
In vivo	Growth plates of young rats, rabbits, and calves	0.1 MPa	—	Compression and distraction were applied over 1 week	—	Reduced growth rate with compression and increased growth rate with distraction	Stokes et al.74
In vivo	Sprague-Dawley rats	0.2 MPa	—	Cyclic compression was applied at 1, 8, or 15 days after seeding	2 weeks	Loading reduced bone growth and no changes were observed in the synthesis of aggrecan, collagen II and collagen X	Cancel et al.82
In vivo	Adult female New Zealand White rabbits	Between 1 and 2 MPa	1	80 cumulative hours in 2-hour increments	3 days a week for 14 weeks	Increment in cartilage deep zone and PG synthesis. No changes in collagen were observed	Saadat et al.84
In vivo (growth plate)	Distal ulnae from 4-week-old swine	1 N	—	A prestrain (5%) was first applied, followed by a stress relaxation test (10% strain)	—	Under compression the cell/matrix volume ratio decreased in the reserve and hypertrophic zones, whereas it increased in the proliferative zone	Amini et al.80
In vivo (growth plate)	Distal ulnae of 4-week-old swine	Strain rate of 1.5E−03 s−1	0.1	The samples were subjected to a 2% strain preload. The static loading samples underwent an additional 10% strain. The dynamic loading samples were submitted to an additional cyclic strain oscillating between 7% and 13% strain	48 hours of stimulation	With static loading cellular columnar organization was preserved, but a loss in aggrecan, type II and type X collagens synthesis was denoted. With dynamic loading, a loss of columnar arrangement was observed in the proliferative and hypertrophic zones, but it contributed to the synthesis of aggrecan and type II collagen	Sergerie et al.81
In vitro (cartilage explant)	Adult articular cartilage from the bovine humeral head	10 kg	0.001, 0.5, 1	At 0.5 Hz and the sine wave amplitude was varied between 5% and 20% of the articular cartilage. The sine wave amplitude was fixed at 10%, while the frequency was varied between 0.001 and 1.0 Hz	45 hours	The oscillatory loading increased protein synthesis, but had an inhibitory influence on PG synthesis. Static compression caused a significant increase in fibronectin synthesis	Wong et al.101
In vitro (cartilage explant)	Articular cartilage explants from 18- to 24-month-old steers	0.1, 1.0, 2.5, or 5.0 MPa	0.001, 0.01, 0.1, or 0.5	Continuously applied, uniaxial cyclic loading was applied for 2 hours	1, 3, or 6 days	When the load was increased, the proteoglycan synthesis was decreased	Steinmeyer et al.102
In vitro (3-dimensional culture)	Femoropatellar from 1- to 2-week-old calves	—	0.001, 0.01, 0.1, and 1	6 hours under static compression; 10 hours under dynamic compression	From 2 to 43 days	Molecular synthesis decreased when static load was applied while with dynamic loading the synthesis was enhanced. Loading enhanced glycosaminoglycans production	Buschmann et al.104
In vitro (3-dimensional culture)	Metacarpal-phalangeal joints of 2-t o 3-year-old free-range steers	—	0.3 and 1	Din unconfined compression for 30 minutes on and 90 minutes off for 16 hours	2 weeks	Contrarily, deposition of larger matrix. Molecules of aggrecan and collagen II was either not affected or inhibited by loading	Farnsworth et al.106