Xiebai Zengye decoction improves respiratory function and attenuates inflammation in juvenile rats with postinfection cough via regulating ERK signaling pathway

This study aimed to determine the effects of Xiebai Zengye decoction (XBZY) on airway inflammation and respiratory function in rats with postinfectious cough (PIC), and its regulatory effects on the extracellular signal-regulated kinase (ERK) signaling pathway. Compared with the normal group, the rats from the PIC group had significantly shortened expiratory time (TE) and enhanced pause (EEP), increased resistance (RT), and enhanced pause (Penh), along with increased levels of serum interleukin-4 (IL-4) and IL-6, and decreased levels of IL-10. The lung and colon tissues of rats from the PIC group showed histopathological changes, including inflammatory cell infiltration, damaged mucosal epithelium, and crypt structure, with significantly increased ERK mRNA and protein expression levels. Treatment with XBZY and montelukast sodium (MAS) improved the respiratory function and serum cytokine levels, reduced tissue inflammation, and decreased ERK mRNA and protein expression levels in the lung and colon tissues. In the lung tissues, XBZY treatment significantly decreased the expression of phosphorylated-ERK (p-ERK) protein, as well as p-MEK1/2, p-ERK1/2, and p-c-Fos proteins, while in the colon tissues, XBZY significantly decreased the expression of p-ERK1/2 and p-c-Fos proteins. However, MAS treatment only showed significant improvement in the lung tissue inflammation score, and the expression level of p-ERK protein in the lung tissue was decreased. In conclusion, the present study suggests that XBZY has a potential therapeutic effect on PIC by improving respiratory function and attenuating inflammation, and this effect may be associated with the inhibition of the ERK signaling pathway. These findings could provide a new direction for the development of treatments for PIC. However, further research is needed to elucidate the underlying molecular mechanisms of XBZY and to confirm its safety and efficacy in clinical trials.