Conditioned serum in vitro treatment of chondrocyte pellets and osteoarthritic explants.

This research examined the effects of autologous conditioned serum (ACS), a treatment used for osteoarthritis in horses, on chondrocytes cells and osteoarthritic cartilage. The study found that while the serum influenced some gene expressions in cultured cells, it did not necessarily improve osteoarthritic conditions in vitro (in lab setting).

Research Methods

• The research employed in vitro experimental models. Specifically, three different serum preparations (PS, PS24h, and PCS) pooled from lame horses were tested.
• Two models were used. The first involved chondrocyte pellet cultures stimulated with the protein IL-1β then treated with the serums for 2 and 48 hours. In the second model, cartilage sections with mild osteoarthritis were treated at set intervals with PS or PCS serum, or left untreated.
• Concentrations of IL-1β and IL-1 receptor antagonist (IL-1Ra) were measured in all the tested serums. Furthermore, microarray, PCR, and matrix metallopeptidase-13 analyses were performed to assess gene expression and cartilage degradation.

Research Findings

• It was found that the concentration of IL-1Ra, a protein that inhibits the activities of IL-1β, was significantly higher in PS24h and PCS serums than in the control PS serum.
• Results showed upregulation of inflammation and cartilage matrix degradation-related genes in all treatment groups compared to the untreated controls. On the other hand, cartilage matrix molecules – aggrecan and collagens – were downregulated in the PS24h- and PCS- treated cells compared to untreated controls.
• Some growth factor signaling genes such as FGF7, BMP2, and INHBA were upregulated in the treatment groups compared to the controls.
• In the osteoarthritis model, the OARSI score, a grading scale for the histological evaluation of articular cartilage, showed no significant difference between treatment groups at the end of the study.

Conclusions

• The research underscored that results obtained from in vitro models might not directly translate to in vivo situations (within living organisms).
• The study concluded that in vitro treatment with conditioned serum did not reduce IL-1β-induced responses in chondrocyte pellets or morphologically improve osteoarthritic cartilage explants.