Assessment of nitric oxide (NO)
The NO concentration in cell suspensions was measured with Griess
reagent (Sigma, G4410). Chondrocytes were pretreated with empagliflozin
at various concentrations (0, 1,
and 5 μM) for 2 h and incubated with IL-1β (10 ng/ml) for 24 h, the NO
levels in the cell culture medium were assessed with Griess reagent
according to the manufacturer. The relative levels of NO were normalized
to cell count.