Objective: To observe the effect of Yangyin Qingfei decoction in regulating T cells Notch signal receptor 1 (Notch1) and Notch signal ligand 1 (Jagged1) in rats with radiation pneumonia

in order to explore its mechanism for preventing and treating radiation pneumonia. Method: Forty male and female SD rats were randomly divided into normal group

model group

hormone group and combination group. The dosage was 16 Gy. On the first day after irradiation

the rats in each group were given the corresponding medicine. At the 4th week after irradiation

the rats were put to death

and their lungs were weighed. The lung tissues were detected by hematoxylin-eosin (HE) staining

Masson staining and Notch1 immunohistochemical staining. Immunohistochemistry was used to extract T cells

and flow cytometry was used to detect Notch1 percentage. The changes in lung function and the expressions of Notch1 and Jagged1 were observed 4 weeks later after irradiation. Result: At the 4th week after radiotherapy

there were significant differences in lung coefficient between groups

and the lung coefficient of normal group was the closest to combined treatment group. Compared with model group

Yangyin Qingfei decoction combined with prednisolone can significantly reduce the proportion of Notch1 T cells (P<0.05)

the expressions of Notch1

NICD and Jagged1 were down-regulated significantly (P<0.05)

and Notch1 and Jagged1 mRNA expressions were significantly decreased (P<0.05). Conclusion: Yangyin Qingfei decoction can significantly reduce Notch1 and Jagged1 expressions of radioactive pneumonia rats

and may be one of prevention and treatment mechanisms for the occurrence and development of radiation pneumonia.