Fig. 2.

Hypo-osmotic challenge inhibits IL-1β mediated NO release via a TRPV4 dependent pathway in isolated chondrocytes and cartilage explants. The TRPV4 antagonist, GSK205, suppresses the anti-inflammatory effects of hypo-osmotic challenge. Nitrite levels measured in the media for (A) isolated cells and (C) cartilage explants in hypo- or iso-osmotic media. Chondrocytes and cartilage explants were treated with and without IL-1β (1 ng/ml) for 24 h and 12 d respectively with and without the TRPV4 inhibitor GSK205 (10 μM). Hypo-osmotic challenge had no effect on cell viability as determined by (B) bright filed images of isolated chondrocytes (D) confocal microscopy of explants stained with Calcein-AM (live cells, green) and ethidium homodimer (dead cells, red). Scale bar represents 100 μm. Data represents mean ± SD for n = 6 separate wells (A) or n = 8 separate explants (C) using cells/explants isolated from 2 different donors. Statistics: Three-way ANOVA and post hoc Tukey's test. # represents statistically significant difference between IL-1β treated and corresponding untreated cells.