Nitric oxide colorimetric assay kit

NK cells were activated with MU1 (5 mg/ml) with 2 ng/ml IL-2 for 5 days or IL2 alone as control group. The pre-activated NK cells were incubated with the target cells (MCF7 or A459 cells) with a 3:1 ratio for 24 h; the induced NO concentrations were quantified using Nitric Oxide Colorimetric Assay Kit (Biovision, United States). Both LPS and INFγ at final concentrations 10 ng/ml was used to induce NK-NO in a positive control group.

Nitric oxide production in peritoneal macrophages was examined by nitrite quantitation using Griess Reagent Kit (Cat# G7921; Thermo Fisher Scientific; Grand Island, New York) according to the manufacturer's protocol. Briefly, peritoneal macrophages were divided equally and plated in the 96-well plate. After LPS and CAY10603 treatment, the cell culture supernatant was collected and mixed with Griess Reagent. The mixture was incubated for 30 min at room temperature. The absorbance was measured at 548 nm using a plate reader. Nitrite concentration was then calculated according to the standard curve.
In Vivo blood nitric oxide levels were examined by nitrite/nitrate quantitation using the Nitric Oxide Colorimetric Assay Kit (Cat#K262; Biovision; Milpitas, California) according to the manufacturer's protocol. Briefly, mouse plasma was collected and filtered through a 10 KDa cutoff filter, then the Nitrate Reductase mixture and the enzyme cofactor were added to the plasma in the plates. The plates were incubated at room temperature to convert nitrate to nitrite. The enhancer and Griess Reagent were then added. After the color was developed for 10 min at room temperature, the absorbance was measured at 540 nm in a plate reader.

NO level and cGMP level in the cavernous tissue in each group were measured using a Nitric Oxide Colorimetric Assay Kit (K262, Biovision, San Francisco, US) and a cGMP direct immunoassay kit (K372, BioVision) according to the manufacturer's protocol.

Nitric oxide release was detected by Nitric Oxide Colorimetric Assay Kit according to the manufacturer's instructions (Biovision, Mountain View, CA).

NO production from transfected cells was determined by measuring nitrite levels in the supernatants. Nitric oxide (NO) is rapidly oxidized to nitrite and nitrate, which can be used to determine NO production. The nitric oxide colorimetric assay kit (Biovision, USA) was used to measure the total nitrate/nitrite in the samples. The measurements were carried out according to the manufacturer’s protocol.

Enzyme-linked immunosorbent assay (ELISA) was performed as the manufacturer’s procedure. Human and mouse IFN-γ, TNF-α, and IL-10 ELISA kits were purchased from PeproTech. Human and mouse TGF-β1 and IL-12p40/p70 ELISA kits were purchased from R&D Systems. For NO level assay, total nitrite/nitrate was measured in cell lysate by using Nitric Oxide Colorimetric Assay Kit (BioVision, K262) according to the suppler’s instructions.