Viability of equine articular chondrocytes in alginate beads exposed to different oxygen tensions.

The research article looks at how different concentrations of oxygen affect the viability of horse joint chondrocytes, which are cells that help maintain cartilage health, in an alginate bead culture over a period of 14 days.

Objective and Approach

• This study aimed to determine how different oxygen (O2) tensions or concentrations impact the viability or survival of equine articular chondrocytes – the cells integral for maintaining cartilage health in horses. This involved isolating these cells from the cartilage of horses’ distal interphalangeal joint (the joint between the second and third phalange bones).
• The researchers then cultivated these cells within alginate beads – a common method for 3D cell culture – under different O2 concentrations: 1%, 5%, and 21% for a total of 14 days. Alginate beads provide structural and mechanical support to cells, simulating the 3D environments cells reside in within living organisms.

Procedure and Outcome Measures

• Cellular growth kinetics were observed over the 14-day period (n=6), with the cells being observed through light microscopy post-staining for detection of necrotic (dead) and apoptotic (programmed cell death) cells.
• To provide insight into the cells’ metabolic status throughout the experiment, the intracellular adenosine triphosphate (ATP) – the molecule that provides energy to drive many processes in living cells – content was measured.

Findings and Conclusions

• The number of chondrocytes was relatively steady for the first eight days and then dropped particularly under 1% and 21% O2. Under the 21% O2 condition, an increase in necrotic cells and a decrease in normal cells was seen by day 14. Only minor changes were observed under 5% O2 except for a decline in necrotic cells by day 14.
• Most apoptotic cells were identified from days 5 to 11 at 1% O2 along with a decrease in normal cells. A surprising rise in normal cells and a decrease in apoptotic cells was observed on the 14th day.
• Throughout the experiment, the intracellular ATP content remained stable, indicating a consistent metabolic status.
• This research concludes that in a 3D culture setup, the level of O2 tension affects the chondrocytes’ survival after an 11-day period, with the significant impacts seen under 21% and 1% O2 conditions.