Effect of ulinastatin on transforming growth factor β1 in rats with radiation-induced lung injury

AIM: To observe the effect of ulinastatin on the expression level of transforming growth factor β1 (TGF-β1) in radiation-induced lung injury and to investigate its roles in treatment of radiation-induced lung injury. METHODS: Sixty female SD rats were divided into 3 groups: normal control group(group C), radiation group (group R), Ulinastatin treatment group(group U). Rats in group R and U were irradiated with linear accelerator at a single dose of 20 Gy. Rats in group U received injection of ulinastatin at a dose of 10 000 u/kg·d for 7 days through vena caudalis immediately after the irradiation and rats in group C and R received the same volume of normal saline. Rats were killed on 7, 15, 30, 60 days. Sections of lung tissues were observed by HE staining and Masson staining. Expressions of TGF-β1 in lung, BALF and serum were determined by immunohistochemistry and ELISA. RESULTS: Densities of lung mesenchyma, positive expression area and concentrations of TGF-β1 gradually increased after irradiation, especially on day 30, 60 in group R. Difference between group R and C was statistically significant(P0.01). Additionally, difference between group U and R was also statistically significant(P0.01). Variations of TGF-β1 in BALF and serum were accordant with the pathological changes in lung after irradiation. CONCLUSION: TGF-β1 plays an important role in radiation-induced lung injury and indirectly reflects the extent of radiation-induced lung injury. Ulinastatin could prevent the inflammatory process and radiation-induced lung injury effectively by inhibiting the level of TGF-β1.