To study the effects of carbocisteine on airway inflammation and airway remodeling in mice with Mycoplasma pneumoniae pneumonia and its mechanism.

Mice were randomly divided into control group, model group, experimental group, negative transfection group and positive transfection group, with 12 mice in each group. The control group were inoculated with 0.9% NaCl by nasal drip, the other groups were inoculated with Mycoplasma pneumoniae suspension to establish Mycoplasma pneumoniae pneumonia model. After successful modeling, the experimental group was given 10 mg·kg^-1 carbocisteine by intragastric administration; the negative transfection group was given 10 mg·kg^-1 carbocisteine by gavage + 1.0×10⁹ PFU of adenovirus containing tumor necrosis factor-α-induced protein 8-like 2 (TIPE2) blank control plasmid in the tail vein, the positive transfection group was given 10 mg·kg^-1 carbocisteine by intragastrial + 1.0×10⁹ PFU containing sh-TIPE2 plasmid was injected into the tail vein, the control and model groups were given 0.9% NaCl by intragastric administration. Five groups were treated for 2 weeks with once a day. The levels of inflammatory factors in lung tissue were detected by enzyme-linked immunosorbent assay. Airway remodeling index and p38 mitogen activated protein kinase (p38MAPK) /activated protein-1 (AP-1) signaling pathway related protein expression were detected by Western blot.

The levels of tumor necrosis factor-α in control, model, experimental, negative transfection and positive transfection groups were (9.18±1.92), (134.32±24.56), (42.20±8.61), (39.95±7.77) and (74.03±13.59) pg·mL^-1; the levels of interleukin-6 were (5.80±1.21), (65.12±11.81), (22.94±4.47), (26.11±5.08) and (42.67±7.97) pg·mL^-1; the relative protein expression levels of matrix metallopeptidase 9 were 1.00±0.16, 3.64±0.62, 1.45±0.22, 1.39±0.20 and 2.16±0.38; the relative protein expression levels of tissue inhibitor of metalloproteinases 1 were 1.00±0.14, 0.52±0.11, 0.89±0.16, 0.84±0.15 and 0.65±0.13; the phospho-p38MAPK/p38MAPK ratios were 1.00±0.16, 2.74±0.48, 1.57±0.29, 1.54±0.27 and 2.31±0.36; the relative protein expression levels of cellular proto-oncogene Jun were 1.00±0.14, 2.25±0.38, 1.34±0.21, 1.37±0.22 and 1.98±0.32; the relative protein expression levels of cellular proto-oncogene Fos were 1.00±0.18, 3.07±0.56, 1.86±0.32, 1.91±0.35 and 2.51±0.44, respectively. The above indexes in the model group were compared with the experimental and control groups, the above indexes in the positive transfection group were compared with the negative transfection group, and the differences were statistically significant (all P<0.05).

Carbocisteine inhibits airway inflammation and airway remodeling in mice with Mycoplasma pneumoniae pneumonia by inhibiting the p38MAPK/AP-1 signaling pathway.