Expression and significance of monocyte chemotactic protein 1 in early radiation-induced lung injury tissue of mice

Abstract

Objective To study the expression and significance of monocyte chemotactic protein 1 (MCP-1) in the process of early radiation-induced lung injury in mice. Methods 40 mice were randomly divided into control group (10 cases) and post-irradiation group (30 cases). A large dose (15 Gy) irradiation on chest was performed in post-irradiation group. Every 10 mice in this group were killed on the 1st day (RT1d), the 10th day (RT10d), the 30th day (RT30d), respectively, and the specimens were collected. The expression of MCP-1 mRNA was detected by quantitative real-time PCR(RT-PCR), and MCP-1 and IL-6 proteins in BALF were detected by ELISA. The pathological changes of lung tissue were observed with HE staining. Results Under the microscope, lung tissue began to show inflammation on the 10th day and was more seriousness on the 30th day in post-irradiation group. Immunohistochemistry staining showed that the expression of MCP-1 in lung tissue irradiated was increased. RT-PCR results showed that the relative expressions of MCP-1 mRNA in control group, RT1d group, RT10d group and RT30d group were 7.63±0.77, 6.81±0.75, 5.75±0.73 and 4.61±0.75, respectively. The differences between RT1d group and control group, RT10d and RT1d group, and RT30d and RT10d were significantly different (all P < 0.05). ELISA results showed that the levels of MCP-1 and IL-6 proteins in post-irradiation group were significantly higher than those in the control group (P < 0.05). Conclusion The expression of MCP-1 in mice after irradiation is abnormal, and MCP-1 may participate in early radiation-induced lung injury. Key words: Radiation; Lung injury; Monocyte chemotactic protein 1; Interleukin-6