Expression And Significance Of MCP-1 In Early Radiation-induced Lung Injury In Mice

Radiotherapy play a pivotal role in the treatment of malignant tumor,and it is one of the main means too.Reported that 60% of lung cancer patients need radiotherapy,and esophageal cancer and other chest tumors also need radiotherapy.The common adverse reactions of radiotherapy for chest tumor is radioactive lung injury,radiation-induced lung injury is an inflammatory reaction in normal lung tissue after irradiation,and it is a common complication of thoracic radiotherapy.For this ten years,with the development of radiotherapy technology has made a qualitative leap,radiation-induced lung injury incidence rate decreased,but it is also inevitable in thoracic radiotherapy,radiation-induced lung injury is one of the main factors limiting the target dose,Because of the lack of awareness in radiation induced lung injury,there is still no effective means in the treatment of this disease,how to effectively prevent and treat radiation induced lung injury is still one of the problems to be solved urgently.With further research about radiation induced lung injury,we all know that the development of radiation induced lung injury is a complex process,which requires interaction of many kinds of cells and cytokines,The experiment has been confirmed that IL-1,IL-6,TGF-?,TNF-a involve in the process of radiation induced lung injury,with IL-6,TGF-? and TNF-a as a treatment target can effectively prevent or reduce the occurrence of radiation-induced lung injury.We want to know if there are other cytokines involved in radiation-induced lung injury.Chemokines is a group of low molecular polypeptide(about 8-10KD),there are four cysteines in front of their molecular structure,according to the first two cysteines whether there are other amino acids,They were divided into four families,named CC,CXC,C and CX3C(X represents any other amino acid),Monocyte chemoattractant protein-1(MCP-1)belongs to the C-C subfamily(beta family members),it is a initiating factor in inflammatory response,MCP-1 can cause macrophages,neutrophils,monocytes and the activative T lymphocyte aggregation,and plays an important role in inflammation.Animal experiments showed that MCP-1 was highly expressed with acquired pneumonia in mice and mycoplasma pneumonia in children.So we speculate that the factor also plays an important role in the development of radiation-induced lung injury.But the literature search has not been found in this report,therefore,we establish an animal model of radiation-induced lung injury and detect the expression of MCP-1 in early radiation-induced lung injury in mice,To explore the role of MCP-1 in process of radiation-induced lung injury,and provide a new effective therapeutic target for preventing and treating radiation induced lung injury.ObjectiveThe purpose of the study is to investigate the expression of MCP-1 in the process of early radiation-induced lung injury in mice,analysis the relationship between MCP-1 and radiation-induced lung injury,and explore the role of MCP-1 in radiation-induced lung injury.Methods40mice were randomly divided into 2 groups,Sham irradiation group(n=10),post–irradiation group(30),A large dose(15Gy)irradiation was performed in the post –irradiation group.Every 10 mice were killed on the second day,the 10 th day,the 30 th day.The expression of MCP-1mRNA was detected by RT-PCR,and MCP-1 and IL-6 in BALF was detected by ELISA.The pathological changes of lung tissue were observed with HE staining.Results1.Lung tissue appears to show inflammation in 10 day post-irradiation group.2.Immunohistochemistry staining showed that the expression of MCP-1 in lung tissue irradiated was enhanced.3.RT-PCR results showed that the relative expression of MCP-1mRNA were significant different in each group,RT1 d group was higher than that of control group,RT10 d above RT1 d group,RT30 d above RT10 d group.4.ELISA results showed that the level of MCP-1 in the post-irradiation group were significantly higher.5.Western blot test results showed that protein expression in lung tissue of mice after irradiation was increased with time extended.Conclusionthe expression of MCP-1 in mice after irradiation was abnormal,MCP-1 may participat in early radiation-induced lung injury.