NO production measurement

The nitrite concentration in conditioned medium was measured as an indicator of NO production according to the Griess reaction. Each supernatant (100 μL) was mixed with the same volume of Griess reagent (1% sulfanilamide in 5% phosphoric acid and 0.1% naphthyl ethylenediamine dihydrochloride in distilled water). The absorbance of the mixture was determined with an ELISA reader (Sunrise, Tecan, Switzerland) at 570 nm [9, 26].