Measurement of MDA, MPO, SOD and CAT levels in lung tissues

Based on the ratio of the weight of the lung tissue (g) and the volume of 0.9% normal saline (ml) (=1:9), the lung tissue in the glass homogenizer was manually homogenized to obtain a 10% homogenate. The homogenate was centrifuged at 4˚C for 10 min at 16,000 x g, and the supernatant obtained after centrifugation was used as the sample. The MDA levels were measured using thiobarbituric acid colorimetry (Malondialdehyde assay kit, cat. no. A003-1-2), and the absorbance of MDA was measured at 532 nm wavelength. The activities of MPO, SOD, and CAT were measured using a colorimetric assay, the xanthine oxidase method, and the UV absorption method, respectively. The activities of CAT, SOD, and MPO were measured using Catalase assay kit (cat. no. A007-2-1), SOD assay kit (cat. no. A001-1-2), and MPO assay kit (cat. no. A044-1-1), respectively, and the absorbance values were measured at wavelengths of 405, 550 and 460 nm, respectively.