Effects of Xinfeng capsule on pulmonary function based on treg-mediated notch pathway in a rat model of adjuvant arthritis

Objective

To observe the impact of xinfeng xapsule (XFC) on pulmonary function in a rat model of adjuvant arthritis (AA) and to investigate the mechanism of action.

Methods

Forty rats were randomly divided into four groups of ten: normal control (NC); model control (MC); tripterygium glycosides tablet (TPT); and xinfeng capsule (XFC). Except for the NC group, AA was induced in all rats by intracutaneous injection of 0.1 mL Freund's complete adjuvant in the right paw on the 19th day. NC and MC groups were given (0.9%) physiological saline. The TPT and XFC groups were given TPT (10 mg/kg) and XFC (1.2 g/kg), respectively. Thirty days after administration, changes in paw edema (E), the arthritis index (AI), pulmonary function, levels of regulatory T-cells (Treg), ultrastructure of lung tissue, and expression of Notch receptors and ligands in lung tissue were observed.

Results

In the MC group, E and the AI were increased and pulmonary function significantly decreased; the structure of alveolar type-II cells was damaged; ratios of Treg in peripheral blood were reduced; and expression of Notch receptors such as Notch3 and Notch4 and ligands such as Delta1 in lung tissue were significantly increased whereas expression of Notch1, Jagged1 and Jagged2 were significantly decreased. After intervention with XFC, E and the AI were decreased; pulmonary function was enhanced; the structure of alveolar type-II cells was improved; and expression of Treg, Notch1, Jagged1, Jagged2 was elevated, whereas that of Notch3, Notch4 and Delta1 was reduced.

Conclusion

XFC can not only inhibit E and the AI and improve joint symptoms, it can also improve pulmonary function and reduce inflammation in lung tissue. These actions could be carried out through increases in the expression of Treg, Notch receptors (Notch1) and ligands (Jagged1, Jagged2), and reductions in the expression of Notch3, Notch4 and Delta1. These phenomena would reduce the deposition of immune complexes and the inflammatory response in lung tissue, thereby improving joint symptoms and pulmonary function.