Pirfenidone inhibits the polarization of M2 macrophages by down-regulating IRF4 to reduce the occurrence and development of radiation-induced lung fibrosis / 中华放射肿瘤学杂志

Objective:To explore the preventive and therapeutic effect of pirfenidone (PFD) on radiation-induced lung fibrosis (RILF) and its mechanism.Methods:40 female C57/BL6 mice were randomly divided into 4 groups: negative control group (NC), PFD treatment group (PFD), radiation treatment group (RT) and radiation plus PFD treatment group (RT+ PFD). Mice in RT and RT+ PFD groups received a single whole lung X-ray consisting of a 50 Gy dose of radiation, delivered by small animal radiation research platform (SARRP). PFD at a dose of 300 mg/kg was administered orally 2 h before irradiation for 150 d. HE and Masson staining were used to detect the infiltration of inflammatory cells and the degree of pulmonary fibrosis. Quantitative real-time PCR (qPCR) and Western blotting (WB) were adopted to detect the expression levels of M1/M2 macrophage phenotypic markers. The expression levels of arginase-1(ARG-1), chitinase 3-like protein 3(YM-1) and interferon regulatory factor-4(IRF4) of macrophages stimulated with IL-4 and IL-13 were detected by WB. In addition, immunofluorescence staining was used to detect the expression and translocation of IRF4 in macrophages among different treatment groups.Results:HE and Masson staining showed that PFD could significantly inhibit radiation-induced infiltration of inflammatory cells and fibrosis in lung tissues. The M2 macrophages and expression levels of ARG-1 and YM-1 were down-regulated in the RT+ PFD group. Cell experiments further confirmed that PFD could significantly inhibit the polarization of macrophages to M2 induced by IL-4+ IL-13, which was mainly related to the down-regulation of IRF4.Conclusion:PFD has a preventive and therapeutic effect on RILF by inhibiting IRF4 and reducing the polarization of macrophages to M2.

Normal lung tissue response following hypofractionated radiation based on radiological parameters / 中华放射医学与防护杂志

Objective@#To study dose-response relationships of fractionated irradiation induced pulmonary fibrosis in mice according to radiological imaging changes of lung.@*Methods@#A total of 8-10 week old-female C57BL6 mice were randomized into different groups for whole thoracic irradiation. The prescribed doses were 0, 2.0, 4.0, 6.0, 7.0, 8.5 Gy per fraction in a total of 5 fractions. CT imaging was performed at 24 weeks post irradiation. The averaged lung density and volume changes were obtained by the three-dimensional segmentation algorithm, and further analyzed in Boltzmann regression modeling.@*Results@#At the endpoint of 24 weeks, the dose-dependent pulmonary radiological alternations were revealed by coronal view of CT images. Translational analysis of fibrosis-related gene-signatures as well as histological collagen stainings further corroborated the radiological findings. According to Boltzmann modeling, the E50 of radiation-induced lung density changes was found to be (30.80±0.80)Gy (adjusted R2=0.97); whereas the E50 for radiation-induced lung volume reduction was determined as (31.31±7.07)Gy (adjusted R2=0.92). Both outcomes indicated a remarkable enhancement of tolerance to normal lung tissues after exposure with 5-fraction versus single fraction scheme.@*Conclusions@#The radiation-induced lung density and volume changes depend not only on total dose, but also the number and dose of fractions.

Dose-response relationship of radiation-induced pulmonary fibrosis in mouse models based on CT-derived parameters / 中华放射肿瘤学杂志

Objective To investigate the radiation induced pulmonary fibrosis with a dose-response mouse model, based on the CT image changes of pulmonary fibrosis.Methods Female C57BL6 mice aged 8-10 weeks were randomly divided into 20 Gy or escalated doses of X-ray whole thoracic irradiation ( WTI) groups. CT scan was performed at different time points before and after radiation. The average lung density and lung volume changes were obtained by three-dimensional segmentation algorithm. After gene chip and pathological validation, the parameters of CT scan were subject to the establishment of logistic regression model. Results At the endpoint of 24 weeks post-irradiation, the lung density in the 20 Gy irradiation group was (-289.81± 12.06) HU, significantly increased compared with (-377.97± 6.24) HU in the control group ( P<0.001) . The lung volume was ( 0.66±0.01) cm3 in the control group, significantly larger than ( 0.44±0.03) cm3 in the irradiated mice ( P<0.001) . The results of quantitative imaging analysis were in accordance with the findings of HE and Mason staining, which were positively correlated with the fibrosis-related biomarkers at the transcriptional level ( all R2=0.75, all P<0.001) . The ED50 for increased lung density was found to be ( 13.64± 0.14) Gy ( R2=0.99, P<0.001) and ( 16.17± 4.36) Gy ( R2=0.89, P<0.001) for decreased lung volume according to the logistic regression model. Conclusions Quantitative CT measurement of lung density and volume are reliable imaging parameters to evaluate the degree of radiation-induced pulmonary fibrosis in mouse models. The dose-response mouse models with pulmonary fibrosis changes can provide experimental basis for comparative analysis of high-dose hypofractioned irradiation-and half-lung irradiation-induced pulmonary fibrosis.

Normal lung tissue response following hypofractionated radiation based on radiological parameters / 中华放射医学与防护杂志

Objective To study dose-response relationships of fractionated irradiation induced pulmonary fibrosis in mice according to radiological imaging changes of lung. Methods A total of 8-10 week old-female C57BL6 mice were randomized into different groups for whole thoracic irradiation. The prescribed doses were 0, 2. 0, 4. 0, 6. 0, 7. 0, 8. 5 Gy per fraction in a total of 5 fractions. CT imaging was performed at 24 weeks post irradiation. The averaged lung density and volume changes were obtained by the three-dimensional segmentation algorithm, and further analyzed in Boltzmann regression modeling. Results At the endpoint of 24 weeks, the dose-dependent pulmonary radiological alternations were revealed by coronal view of CT images. Translational analysis of fibrosis-related gene-signatures as well as histological collagen stainings further corroborated the radiological findings. According to Boltzmann modeling, the E50 of radiation-induced lung density changes was found to be (30.80±0.80)Gy (adjusted R2 =0.97);whereas the E50 for radiation-induced lung volume reduction was determined as ( 31. 31 ± 7. 07 ) Gy(adjusted R2=0. 92). Both outcomes indicated a remarkable enhancement of tolerance to normal lung tissues after exposure with 5-fraction versus single fraction scheme. Conclusions The radiation-induced lung density and volume changes depend not only on total dose, but also the number and dose of fractions.

CT-based quantitative evaluation of radiation-induced lung fibrosis: a study of interobserver and intraobserver variations

PURPOSE: The degree of radiation-induced lung fibrosis (RILF) can be measured quantitatively by fibrosis volume (VF) on chest computed tomography (CT) scan. The purpose of this study was to investigate the interobserver and intraobserver variability in CT-based measurement of VF. MATERIALS AND METHODS: We selected 10 non-small cell lung cancer patients developed with RILF after postoperative radiation therapy (PORT) and delineated VF on the follow-up chest CT scanned at more than 6 months after radiotherapy. Three radiation oncologists independently delineated VF to investigate the interobserver variability. Three times of delineation of VF was performed by two radiation oncologists for the analysis of intraobserver variability. We analysed the concordance index (CI) and inter/intraclass correlation coefficient (ICC). RESULTS: The median CI was 0.61 (range, 0.44 to 0.68) for interobserver variability and the median CIs for intraobserver variability were 0.69 (range, 0.65 to 0.79) and 0.61(range, 0.55 to 0.65) by two observers. The ICC for interobserver variability was 0.974 (p < 0.001) and ICCs for intraobserver variability were 0.996 (p < 0.001) and 0.991 (p < 0.001), respectively. CONCLUSION: CT-based measurement of VF with patients who received PORT was a highly consistent and reproducible quantitative method between and within observers.

The mechanisms of ARPD in treating radiation-induced lung fibrosis in rats / 中华放射医学与防护杂志

Objective To investigate the therapeutic effects and mechanism of anti-radiation pneumonia decoction(ARPD) on radiation induced lung fibrosis in rats.Methods One hundred and five male SD rats in a SPF grade were divided into Chinese medicine group,single radiation group and control group by random digits table method,with 35 in each group.After anesthetization,rats in Chinese medicine and single radiation groups were exposed to 6 MV X-rays at the dose of 15Gy.Rats in Chinese medicine group were treated with ARPD at the dosage of 10 ml·kg-1 ·d-1 once a day,but rats in single radiation group did not receive ARPD treatment.Rats in control group were treated with neither irradiation nor drugs.Five rats of each group were killed and the lung tissues and blood samples were collected at 15,30,60,75,90,105 and 140 d.The pathological changes of lung tissues were observed and the tissue protein and gene expressions of TGF-β1,PAI-1 and collagen type Ⅲ(C Ⅲ) were assayed by Western blot and RT-PCR.ELISA was used to detect serum TGF-β1 and plasma PAI-1.Tissue and serum HYP were determined by acid hydrolysis and alkaline hydrolysis methods respectively.Results Inflammation was found in the lung tissues of all the exposed rats.Obvious pathological lung fibrosis was found at 60 d,the inflammation and the fibrosis in treated group were slighter than those in single radiation group.In Chinese medicine group,the protein and gene expression levels of TGF-β1,PAI-1,C Ⅲ 30 d(Protein:t =2.49-3.74,t =2.63-4.57 and t =2.76-3.83;Gene:t =2.59-4.33,t =2.83-4.62 and t =2.83-3.96,P＜0.05),serum TGF-β1 and plasma PAI-1 15 dlater (t =2.85-6.27 and t =3.69-5.27,P＜0.05),and the levels of tissue and serum HYP60 dlater (t=3.65-4.40 and t =6.56-3.75,P＜0.05),all of them were lower than those in single radiation groups.There were significant positive correlations between tissue TGF-β1 and PAI-1 as well as C Ⅲ (Protein expression:r =0.604,0.759,P ＜0.05;Gene expression:r=0.519,0.816,P＜0.05).Conclusions ARPD may inhibit the pulmonary fibrosis by decreasing the levels of TGF-β1,PAI-1 and C Ⅲ.

Expression of GATA-3 in mice with radiation-induced lung fibrosis / 中华放射医学与防护杂志

Objective To observe the expression of GATA-3 and IL-13 in mice with radiationinduced lung fibrosis,and to study the function of GATA-3.Methods A total of 63 C57BL/6 female mice were randomly into 2 groups,including 21 mice in control group and 42 mice in irradiated group.The thoraces of mice in irradiated group were exposed with 12 Gy of X-rays.All the mice were sacrificed at 1 h,and 1,2,4,8,16 and 24 weeks post-irradiation.The lung issues were stained by using HE and Masson methods to determine the histological changes.The expression of IL-13 in serum,and the expression of hydroxyproline and the mRNA and protein of GATA-3 in lung tissue were assayed.Results Compared with control group,there was a significant histological and pathologic change in irradiated group.The content of hydroxyproline in irradiated group was significantly higher than that in control group( Z =3.14,P ＜0.05).The expressions of GATA-3 and IL-13 were found in mice post-irradiation.Without causing conspicuous fibrotic pathological changes,there was a significantly elevated expression of Th2-specific transcription factor GATA-3 mRNA at 1 and 2 weeks post-irradiation ( t =6.50,6.33,P ＜ 0.01 ),while the expression of IL-13 reached the maximal value in serum at 16 weeks post-irradiation( t =32.21,P ＜0.01 ).Conclusions GATA-3 might play a role in promoting radiation-induced pulmonary fibrosis by upregulation of expression of Th2 cytokine IL-13.