Objective To investigate the protective mechanism of oxidative stress injury of SD rats NR8383 by budesonide.Methods Rat alveolar macrophages NR8383 were divided into 5 groups:blank group was given serum-free K12 medium without any treatment;lipopolysaccharide(LPS)group was given 2.29 μg·mL-1 LPS standard solution;budesonide group(budesonide),c-Jun inhibitor group(AS601245)and budesonide+c-Jun inhibitor group(budesonide+AS601245)were given budesonide 28.0 μL,c-Jun inhibitor AS601245 2.50 μg,and budesonide 28.0 μL+c-Jun inhibitor AS601245 2.50 μg based on the LPS group,respectively.Cells in 5 groups were incubated in serum-free K12 medium at constant temperature for 24 h.The apoptosis rate at 24 h was examined by cell counting kit-8(CCK-8)assay;c-Jun mRNA expression was detected by real-time quantitative polymerase chain reaction(q-PCR);oxidative stress damage factor reactive oxygen species(ROS),8-hydroxy-2-deoxyguanosine(8-OHdG),glutathione peroxidase(GSH-Px),thioredoxin reductase-1(TRX-1)expression were detected by enzyme-linked immunosorbent assay(ELISA);c-Jun signaling pathway protein expression in each group by Western blot.Results Compared with LPS group(29.88±5.98)%,24 h apoptosis rate was significantly decreased in budesonide group,c-Jun inhibitor group,budesonide+c-Jun inhibitor group and blank group[(20.15±6.66)%,(15.39±3.54)%,(12.11±2.55)%and(8.52±1.27)%,respectively],the differences were statistically significant(all P<0.05).The ROS in budesonide group,c-Jun inhibitor group,budesonide+c-Jun inhibitor group,LPS group and blank group were(3.16±0.19),(4.15±0.33),(2.21±0.21),(6.52±0.36)and(1.06±0.23)U·g-1;8-OHdG were(10.55±1.23),(11.14±1.06),(9.55±1.00),(15.66±1.99)and(8.27±1.13)ng·mL-1;GSH-PX were(188.52±12.33),(200.52±27.97),(144.52±20.55),(335.14±30.10)and(126.55±12.52)U·mL-1;TRX-1 were(40.11±6.66),(50.55±10.07),(60.25±10.55),(115.36±20.03)and(16.55±2.33)ng·mL-1;the relative c-Jun mRNA expressions were 0.56±0.03,0.44±0.11,0.25±0.04,0.89±0.12 and 0.08±0.01;c-Jun/GAPDH protein relative expression were 3.15±0.22,2.36±0.14,1.55±0.13,4.02±0.22 and 0.88±0.12.Compared with the LPS group,the differences of indicators in the budesonide group,c-Jun inhibitor group and budesonide+c-Jun inhibitor group possessed statistical significance(all P<0.05).Conclusion Budesonide significantly increased the survival rate of NR8383 cells and significantly decreased the concentrations of oxidative damage representative factors ROS,GSH-Px,8-OHdG and TRX-1,its oxidative damage protection mechanism may be related to the regulation of c-Jun protein.