Passive osmotic properties of in situ human articular chondrocytes within non-degenerate and degenerate cartilage
Article first published online: 24 JAN 2005
Copyright © 2005 Wiley-Liss, Inc.
Journal of Cellular Physiology
Volume 204, Issue 1, pages 309–319, July 2005
How to Cite
Bush, P. G. and Hall, A. C. (2005), Passive osmotic properties of in situ human articular chondrocytes within non-degenerate and degenerate cartilage. J. Cell. Physiol., 204: 309–319. doi: 10.1002/jcp.20294
- Issue published online: 25 APR 2005
- Article first published online: 24 JAN 2005
- Manuscript Accepted: 10 NOV 2004
- Manuscript Received: 9 SEP 2004
- Arthritis Research Campaign. Grant Number: H0621
- Wellcome Trust. Grant Number: 045925/Z/95/A
Osteoarthritis is characterized by many factors, including proteoglycan loss, decreased collagen stiffness, and increased cartilage hydration. Chondrocyte swelling also occurs, and correlates with the degree of osteoarthritis, however, the cause is unknown but might be related to alterations to their passive osmotic properties. We have used two-photon confocal laser scanning microscopy to measure the passive osmotic characteristics of in situ chondrocytes within relatively non-degenerate and degenerate human tibial plateau cartilage, and in chondrocytes isolated from relatively non-degenerate cartilage. Explants with bone attached were taken from a total of 42 patients undergoing arthroplasty and graded macroscopically and microscopically into two groups, grade 0 + 1 and grade 2 + 3. There was a significant increase in cartilage hydration between these two groups (P < 0.05), however, there was no change when medium osmolarity was varied over ∼0–480 mOsm. The passive osmotic behavior of in situ chondrocytes (at 4°C) was identical over a range of culture medium osmolarities (∼0–515 mOsm), however, the maximum swelling of cells within degenerate cartilage and isolated chondrocytes was greater compared to those in non-degenerate cartilage. The swelling in the majority of in situ chondrocytes was accounted for by the reduced interstitial osmolarity occurring with cartilage degeneration. There was, however, a small population of in situ chondrocytes whose volume was in excess (≥2,500 μm3) of that predicted from the decreased interstitial osmotic pressure. These results show that for the majority of cells studied, the differences in passive chondrocyte volume between relatively non-degenerate, degenerate, and isolated cells were entirely accounted for by changes to the extracellular osmolarity (180–515 mOsm). © 2005 Wiley-Liss, Inc.