Analysis of Pulmonary Injury and Inflammatory Cytokines in BALF

In order to evaluate cytotoxicity as a measure of lung damage, lactate dehydrogenase (LDH) activity and total protein (TP) levels in the BALF of all exposed groups were measured at each time point after exposure. LDH activity in the BALF was measured by LDH cytotoxicity test kit. The TP concentration in the BALF was determined by the Bradford method and Bio-Rad Protein Assay. The levels of pro-inflammatory and anti-inflammatory cytokines in BALF, including tumor necrosis factor (TNF)-α and interleukin (IL)-6, were measured using enzyme-linked immunosorbent assay (ELISA) kits (Nanjing Jiancheng Bioengineering Institute, Nanjing, China), according to the instructions provided.