Objective:To observe the effect of methylprednisolone (MP) combined with cyclophosphamide (CTX) on inflammation and immune cell activity in bleomycin (BLM)-induced pulmonary fibrosis rat model.Methods:Forty healthy 6 to 8-week-old SD rats were randomly divided into blank control, BLM model, BLM+MP, and BLM+MP+CTX groups, with 10 rats in each group. The rat model of pulmonary fibrosis was prepared by intratracheal infusion of BLM (5 mg/kg, only once). From the 7th day of modeling, MP (3 mg/kg) was injected in rats in the BLM+MP group and MP (3 mg/kg)+CTX (8 mg/kg) was injected via tail vein in rats in the BLM+MP+CTX group, once daily for 21 days. The degree of lung inflammation and fibrosis in rats was detected using HE and Masson staining methods. The numbers of granu-locytes and neutrophils in bronchoalveolar lavage fluid (BALF) and blood T cell subsets in rats were detected using flow cytometry.Results:On the 7th day of modeling, the external morphology, HE and Masson staining results of rat lung tissue showed that BLM-induced pulmonary fibrosis model was successfully prepared. On the 28th day of modeling, the lung tissue structure of the BLM group was disordered with obvious collagen deposition, the number of granulocytes and neutrophils in BALF increased significantly, the proportion of blood T cells, CD4 + T cells, and regulatory T cells (Tregs) decreased, the proportion of CD8 + T cells, and the CD4 +/CD8 + T cells ratio decreased significantly (all P<0.05). Compared with the BLM group, the degree of pulmonary fibrosis in the BLM+MP+CTX group was improved significantly, the number of granulocytes and neutrophils in BALF decreased significantly, the proportion of blood T cells, CD4 + T cells and Tregs cells increased significantly, the proportion of CD8 + T cells decreased, and the ratio of CD4 +/CD8 + T cells increased significantly (all P<0.05). The improvement effect in rats of BLM+MP+CTX group was better than that of BLM+MP group, and the difference was statistically significant ( P<0.05). Conclusion:MP combined with CTX can reduce the degree of inflammatory reaction in rats with pulmonary fibrosis and improve T cell immune activity.

Objective:To observe the effect of methylprednisolone (MP) combined with cyclophosphamide (CTX) on inflammation and immune cell activity in bleomycin (BLM)-induced pulmonary fibrosis rat model.Methods:Forty healthy 6 to 8-week-old SD rats were randomly divided into blank control, BLM model, BLM+MP, and BLM+MP+CTX groups, with 10 rats in each group. The rat model of pulmonary fibrosis was prepared by intratracheal infusion of BLM (5 mg/kg, only once). From the 7th day of modeling, MP (3 mg/kg) was injected in rats in the BLM+MP group and MP (3 mg/kg)+CTX (8 mg/kg) was injected via tail vein in rats in the BLM+MP+CTX group, once daily for 21 days. The degree of lung inflammation and fibrosis in rats was detected using HE and Masson staining methods. The numbers of granu-locytes and neutrophils in bronchoalveolar lavage fluid (BALF) and blood T cell subsets in rats were detected using flow cytometry.Results:On the 7th day of modeling, the external morphology, HE and Masson staining results of rat lung tissue showed that BLM-induced pulmonary fibrosis model was successfully prepared. On the 28th day of modeling, the lung tissue structure of the BLM group was disordered with obvious collagen deposition, the number of granulocytes and neutrophils in BALF increased significantly, the proportion of blood T cells, CD4 + T cells, and regulatory T cells (Tregs) decreased, the proportion of CD8 + T cells, and the CD4 +/CD8 + T cells ratio decreased significantly (all P<0.05). Compared with the BLM group, the degree of pulmonary fibrosis in the BLM+MP+CTX group was improved significantly, the number of granulocytes and neutrophils in BALF decreased significantly, the proportion of blood T cells, CD4 + T cells and Tregs cells increased significantly, the proportion of CD8 + T cells decreased, and the ratio of CD4 +/CD8 + T cells increased significantly (all P<0.05). The improvement effect in rats of BLM+MP+CTX group was better than that of BLM+MP group, and the difference was statistically significant ( P<0.05). Conclusion:MP combined with CTX can reduce the degree of inflammatory reaction in rats with pulmonary fibrosis and improve T cell immune activity.