Objective: To investigate the mechanisms and effects of glycyrrhizin in rat model of pulmonary fibrosis produced by Bleomycin. Method: Sprague Dawley rats(180±20) g were randomLy divided into 4 groups: pulmonary fibrosis group

NS group

DXM treatment group

glycyrrhizin treatment group.There were ten rats in every group.All rats in the treatment groups were intraperitoneal injection after 28 days when rats were produced pulmonary fibrosis

which was at the same time every day and lasts for 14 days.The treatment dose were DXM 3 mg/(kg ·d)

glycyrrhizin dose 150 mg/(kg ·d).After the 15th days

Lung tissues were obtained

the left lung(1 cm×1 cm×lcm) was fixed in 10% formaldehyde

which were measured by immunity class TGF-β1

IFN-γ;the right lung was made into slice which cell apoptosis was detected.To draw 6~8 mL blood of the rats in all treatment groups and stand for 30 minutes

we can obtain blood-serum after the blood centrifuged for 15 mnutes

and the blood-serum war measured by ELISA TGF-β1、IFN-γ and IL-4. Result: 1.The extent of alveolitis and fibrosis of pulmonary fibrosis rats were quantified by grades. The pulmonary alveolitis and fibrosis of glycyrrhizin group and DXM group were signifieantly lighter than BLM group.2.Stronger TGF-β1 protein expression was deteeted in bronehiolar epitheliums of BLM group

poorer IFN-γ in BLM group.But the oppositions were in glycyrrhizin group and DXM group. TGF-β1 protein expression in BLM group was more significant deviation than in NS group(P=0.007)

DXM group(P=0.000)

glycyrrhizin group(P=0.001)

but the difference was obvious between DXM group and glycyrrhizin group(P=0.018); IFN-γ protein expressions in glycyrrhizin group(P=0.004) and in DXM group(P=0.01) were more significant deviation than in BLM group.But IFN-γ protein expression no deviation between DXM group and glycyrrhizin group(P=0.618);3.The TGF-β1and IL-4 levels of BLM group were higher than all the treatment groups

but the IFN-γ level was contrary. The TGF-β1 level of BLM group was more deviative than glycyrrhizin group(P=0.005)

DXM group(P=0.044)

NS group(P=0.008); The IL-4 levels of NS group(P=0.013)

DXM group(P=0.029)

glycyrrhizin group(P=0.013)were more deviative than in BLM group; The IFN-γ leve of BLM group was more poorer than DXM group(P=0.001)and glycyrrhizin group(P=0.000)

But the IFN-γ leve no deviation between DXM group and glycyrrhizin group(P=0.389). Conclusion: The study shows rats pulmonary fibrosis in the glycyrrhizin treatment group was less severe than that of BLM group. TGF-β1 and IL-4 protein expressions in the glycyrrhizin treatment group were poorer than in BLM group. The TGF-β1and IL-4 levels were the same.But IFN-γ protein expression and the IFN-γ leve in glycyrrhizin group were stronger.