ABSTRACT
Objective To explore the role of pulmonary function analysis in drug efficacy evaluation of radiation-induced lung injury.Methods Totally 30 C57BL/6 mice were randomly divided into 3 groups:control group, radiation group and dexamethasone group.Mice in radiation group and dexamethasone group were irradiated with 20 Gy X-ray on the whole chest.Then mice in dexamethasone group was intraperitoneally injected with dexamethasone at the dose of 4.5 mg/( kg· d) for 2 weeks and then the dose was halved up to 1 month after radiation while control group and radiation group were intraperitoneally injected with 0.9%saline.One month after irradiation, pulmonary function of all the mice was tested with EMKA system.Then mice were sacrificed and pathological changes of pulmonary tissue were observed by HE staining. Furthermore, the area of alveolar cavity was measured with the Image-pro plus software.Results One month after irradiation, the pulmonary function parameters of mice in radiation and dexamethasone groups, such as mid-expiratory flow, minute volume,tidal volume,peak inspiratory flow,and peak expiratory flow,decreased obviously compared with the control group, but those parameters of the dexamethasone group decreased much less significantly than in the radiation group.The pathological changes of pulmonary tissues showed that the area of alveolar cavity of radiation group and dexamethasone group was smaller than that of the control group, but the extent of the loss of alveolar cavity area of the dexamethasone group was less than in the radiation group.Neutrophils infiltration could be found in the radiation group and dexamethasone group, but was less serious in the dexamethasone group.The result of pulmonary function analysis was coincident with pathological changes of the lung.Conclusion Dexamethasone can alleviate radiation induced pulmonary injury.Pulmonary function analysis combined with pathological observation of pulmonary tissues can effectively evaluate the efficacy of drugs in radiation induced lung injury.