Radiation-induced Lung Injury In Rats Research Articles

Serum Metabolomic Analysis of Radiation-Induced Lung Injury in Rats.

Radiation-induced lung injury is a common complication of radiotherapy for lung cancer, breast cancer, esophageal cancer, and thymoma. This study aims to illustrate biomarkers of radiation-induced lung injury and its potential mechanism through the study of metabolomic alterations in serum of Sprague-Dawley rats with different radiation doses. Serum from 0, 10, or 20 Gy irradiated rats were collected and subjected to gas chromatography-mass spectrometry. The result showed that there were 23 dysregulated metabolites between the 10 Gy irradiation group and the 0 Gy control group, whereas 36 preferential metabolites were found between the 20 Gy irradiated rat serum and the control groups. Among them, there were 19 common differential metabolites in the 2 irradiation groups, including 3 downregulated (benzyl thiocyanate, carbazole, and N-formyl-L-methionine) and 16 upregulated metabolites. We further analyzed the metabolic pathways of different metabolites; the results showed that there were 3 significant enrichment pathways in the 10 Gy vs 0 Gy group and 7 significant enrichment pathways in the 20 Gy vs 0 Gy group. Among them, taurine and hypotaurine metabolism, riboflavin metabolism, and glyoxylate and dicarboxylate metabolism were the common metabolic enrichment pathways of the 10 Gy vs 0 Gy group and the 20 Gy vs 0 Gy group.

Transcriptome analysis of mild hypothermia protection against radiation-induced rat lung injury based on RNA-seq.

To analyze the differentially expressed genes (DEGs) with radiation-induced rat lung injury, and to reveal the protective mechanism for mild hypothermia in the radiation-induced lung injury in rats at the transcriptome level. A total of 10 male SD rats aged 6-8 weeks were randomly divided into 2 groups to establish a rat model of radiation-induced lung injury, and one group was treated with mild hypothermia. RNA was extracted from left lung tissue of each group, and sequenced by BGISEQ-500 platform. Significance analysis of DEGs was carried out by edgeR software. Gene ontology (GO) function enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to analyze the gene function. Then 5 key DEGs were verified by real-time reverse transcription PCR (real-time RT-PCR). There were 2 790 DEGs (false discovery rate<0.001, |log2(fold change)|>1) in the mild hypothermia group compared with the model group, in which 2 257 genes were up-regulated and 533 genes were down-regulated. When real-time RT-PCR was used to validate the 5 key genes, the result was consistent with the RNA-seq. GO functional enrichment analysis showed that these DEGs were related to cell binding, metabolic process and cell membrane structure, etc. KEGG pathway enrichment analysis showed that these genes were involved in important biological pathways such as cell adhesion molecules, mammalian target of rapamycin, tight junction, and NF-κB. The DEGs and pathways related to mild hypothermia protection against radiation-induced lung injury in rats are obtained, which provides an experimental basis for the protection of mild hypothermia against radiation-induced lung injury.

Investigation of the radioprotective effect of arbutin on radiation-induced lung injury in rats: a histopathological study

Background: Radiaton-induced lung injury is a common complicaton after esophageal, breast, etc. cancer radiotherapy. We aimed to evaluate the radioprotectve effect of arbutn on acute radiaton-induced lung damage in male rats. Materials and Methods: Fifty-two male Wistar rats were divided into 4 groups: (i) control group (n = 10), (ii) vehicle group (n = 10, received distlled water intraperitoneally (ip)), (iii) X-irradiaton only (n=16, chest was irradiated to a single dose of 20 Gy x-rays) and (iv) arbutn + X-irradiaton (n=16, 75 mg/kg of arbutn 2 hours before irradiaton (ip), and then their chest was exposed to 20 Gy x-rays). For histopathological investgaton, 8 animals of each group were sacrificed 8 weeks after treatment and the rest of them were sacrificed 3 months after treatment. Results: The histopathological analysis in 8 weeks after X-irradiaton showed that there was a significant increase in inflammatory in X-irradiaton only group compared to control group. The administraton of arbutn 2 hours prior to X-irradiaton significantly reduced inflammaton and inflammatory factors such as macrophages, mast cell and neutrophil in arbutn + X-irradiaton group compared to X-irradiaton only group (P<0.05). The histopathologic investgaton performed 3 months after lung irradiaton indicated a significant reducton in fibrosis formaton in arbutn + X-irradiaton group compared to irradiaton only group (P<0.05). Localized chest X-irradiaton with 20 Gy caused histopathologic damage to the lungs for short-term. Conclusion: Arbutn has a great potental in reducing the histopathologic damage to lung tssue after thoracic irradiaton. © 2020 Novin Medical Radiation Institute. All rights reserved.

Metabolomic Analysis of Radiation-Induced Lung Injury in Rats: The Potential Radioprotective Role of Taurine.

Radiation-induced lung injury is a major dose-limiting toxicity that occurs due to thoracic radiotherapy. Metabolomics is a powerful quantitative measurement of low-molecular-weight metabolites in response to environmental disturbances. However, the metabolomic profiles of radiation-induced lung injury have not been reported yet. In this study, male Sprague-Dawley rats were subjected to a single dose of 10 or 20 Gy irradiation to the right lung. One week after radiation, the obvious morphological alteration of lung tissues after radiation was observed by hematoxylin and eosin staining through a transmission electron microscope. We then analyzed the metabolites and related pathways of radiation-induced lung injury by gas chromatography–mass spectrometry, and a total of 453 metabolites were identified. Compared to the nonirradiated left lung, 19 metabolites (8 upregulated and 11 downregulated) showed a significant difference in 10 Gy irradiated lung tissues, including mucic acid, methyl-β-d-galactopyranoside, quinoline-4-carboxylic acid, and pyridoxine. There were 31 differential metabolites (16 upregulated and 15 downregulated) between 20 Gy irradiated and nonirradiated lung tissues, including taurine, piperine, 1,2,4-benzenetriol, and lactamide. The Kyoto Encyclopedia of Genes and Genomes–based pathway analysis enriched 32 metabolic pathways between the irradiated and nonirradiated lung tissues, including pyrimidine metabolism, ATP-binding cassette transporters, aminoacyl-tRNA biosynthesis, and β-alanine metabolism. Among the dysregulated metabolites, we found that taurine promoted clonogenic survival and reduced radiation-induced necrosis in human embryonic lung fibroblast (HELF) cells. This study provides evidence indicating that radiation induces metabolic alterations of the lung. These findings significantly advance our understanding of the pathophysiology of radiation-induced lung injury from the perspective of metabolism.

Cryptotanshinone Ameliorates Radiation-Induced Lung Injury in Rats.

Cryptotanshinone (CTS) was reported to repress a variety of systemic inflammation and alleviate cardiac fibrosis, but it is still unclear whether CTS could prevent radiation-induced lung injury (RILI). Here, we investigated the effects and underlying mechanisms of CTS on a RILI rat model. Our data revealed that CTS could efficiently preserve pulmonary function in RILI rats and reduce early pulmonary inflammation infiltration elicited, along with marked decreased levels of IL-6 and IL-10. Moreover, we found that CTS is superior to prednisone in attenuating collagen deposition and pulmonary fibrosis, in parallel with a marked drop of HYP (a collagen indicator) and α-SMA (a myofibroblast marker). Mechanistically, CTS inhibited profibrotic signals TGF-β1 and NOX-4 expressions, while enhancing the levels of antifibrotic enzyme MMP-1 in lung tissues. It is noteworthy that CTS treatment, in consistent with trichrome staining analysis, exhibited a clear advantage over PND in enhancing MMP-1 levels. However, CTS exhibited little effect on CTGF activation and on COX-2 suppression. Finally, CTS treatment significantly mitigated the radiation-induced activation of CCL3 and its receptor CCR1. In summary, CTS treatment could attenuate RILI, especially pulmonary fibrosis, in rats. The regulation on production and release of inflammatory or fibrotic factors IL-6, IL-10, TGF-β1, NOX-4, and MMP-1, especially MMP-1 and inhibition on CCL3/CCR1 activation, may partly attribute to its attenuating RILI effect.

Experimental studies on the protective effects of the over-expression of lentivirus-mediated SIRT6 on radiation-induced lung injury

Objective: To investigate the protective effects of the over-expression of SIRT6 on radiation-induced lung injury in rats. Methods: 72 male Wistar rats (150-120 g) were randomly divided into 3 groups (n=24). Models were made through radiating both lungs with a 6 MV-X linear accelerator. Each group was injected through the tail vein with normal saline (the control group and radiation group) and lentivirus carrying overexpressed SIRT6 (Lent-SIRT6 group) on the exact day of modeling. Changes in respiratory rates, body weight and levels of TNF-α and IL-6 in serum were measured respectively at 1, 2, 4 and 8 weeks after radiation. Blood routine indexes (RBCs, neutrophils and lymphocytes) were recorded, rats were sacrificed with their lung tissues taken, pathological changes of lungs were evaluated by HE staining and TNF-α, IL-6 and IL-1β were detected with ELISA at 8 weeks after radiotherapy. Results: The lung structure including alveolar walls and interstitium in control group were normal, but alveolar walls in radiation group were obviously thickened and a large amount of hyperplastic fibrous tissues were found in alveolar interstitium, while the thickness and interstitial fibrosis of alveolar walls were more alleviated in Lent-SIRT6 group than in radiation group. Compared with those in control group, the respiratory rates, levels of TNF-α and IL-6 in serum, neutrophils and levels of TNF-α, IL-6 and IL-1β in liver all were increased, while WBCs and lymphocytes were decreased in radiation group. The differences were statistically significant (P<0.05). The respiratory rates, levels of TNF-α and IL-6 in serum, neutrophils and levels of TNF-α, IL-6 and IL-1β in liver were all decreased, and WBC and lymphocytes were increased after injection with over-expressed SIRT6. The differences were statistically significant (P<0.05). Conclusion: SIRT6 inhibits inflammation and alleviates radioactive pneumonia and lung injury. Therefore, SIRT6 can exert certain protective effects on lung injury.

Captopril attenuates lung inflammation through inhibiting the expression of CCL-2 in rats with acute radiation-induced lung injury

Objective To explore the inhibitory effect of captopril on acute radiation-induced lung injury in rats and the possible mechanism. Methods Sixty-four female Wistar rats were randomly divided into control group, irradiation group, irradiation+ low-dose captopril group, and irradiation+ high-dose captopril group. A single dose of 20 Gy was given to the right lung of all rats except those in the control group to establish a rat model of acute radiation-induced lung injury. These rats were sacrificed at 1, 2, 4, and 8 weeks. HE staining was used to observe the pathological changes in lung tissue; RT-PCR and Western blot were used to measure the mRNA and protein expression of CCL-2 in lung tissue; immunohistochemical assay was used to determine the number of monocytes (CD68) in lung tissue. A one-way analysis of variance was performed. Results Captopril significantly reduced lung inflammation in rats with acute radiation-induced lung injury (P<0.05), inhibited the accumulation of monocytes (CD68) in lung tissue (P<0.05), and decreased the content of CCL-2 in lung tissue (P<0.05). Conclusions For rats with acute radiation-induced lung injury, captopril can reduce the expression of CCL-2 to inhibit the accumulation of monocytes in lung tissue and thus attenuate lung inflammation. Key words: Captopril; Rat; Acute radiation-induced lung injury; Chemoattractant cytokine ligand 2; Macrophage

Intravenous delivery of adipose-derived mesenchymal stromal cells attenuates acute radiation-induced lung injury in rats

Background aimsRadiation-induced lung injury (RILI) commonly occurs in patients with thoracic cancer. However, an effective treatment option has not yet been established. Adipose-derived mesenchymal stromal cells (Ad-MSCs) have significant potential for clinical use, but their role in RILI is currently unknown. We aimed to evaluate the therapeutic capacity of Ad-MSCs to heal acute RILI in rats. MethodsSprague-Dawley rats were used in this study. Rat Ad-MSCs were delivered through the tail veins of rats 2 h after thorax irradiation. Lung histopathologic findings, pulmonary levels of inflammatory cytokines (interleukin [IL]-1, IL-6, IL-10 and tumor necrosis factor-α), pro-fibrotic factors (transforming growth factor [TGF]-β1, connective tissue growth factor, α-smooth muscle actin and type 1 collagen), pro- or anti-apoptotic mediators (Bcl-2, Bax and caspase-3) and the multifunctional factor hepatocyte growth factor were evaluated after Ad-MSC transplant. ResultsIntravenous delivery of Ad-MSCs attenuated acute RILI. Further studies showed that Ad-MSCs had anti-inflammation and anti-fibrotic effects and maintained lung epithelium integrity, as indicated by reduced serum levels of the pro-inflammatory cytokines IL-1, IL-6 and tumor necrosis factor-α, increased levels of the anti-inflammatory cytokine IL-10, and downregulated transforming growth factor -β1, α-smooth muscle actin and type 1 collagen levels in irradiated lung tissues. Ad-MSCs also regulated the expression of pro- and anti-apoptotic mediators (Bcl-2, Bax and caspase-3) to protect lung cells from apoptosis. ConclusionsIntravenous Ad-MSC delivery attenuated acute RILI through anti-inflammation, anti-fibrosis and anti-apoptosis mechanisms.

Effect of Yangyinqingfei decoction on radiation-induced lung injury via downregulation of MMP12 and TIMP-1 expression.

The aim of this study was to evaluate the effect and underlying mechanism of Yangyinqingfei decoction on radiation-induced lung injury in rats. Wistar rats (n=75) were randomly divided into five experimental groups (A-E). Rats in two of the groups were administered saline solution, whereas rats in the remaining three groups were administered different doses of Yangyinqingfei decoction. After one week, the rats were irradiated with a single dose of 25 Gy to their right hemi-thoraxes by a 60Co γ-ray, with the exception of the control group, which underwent sham irradiation. The effect of Yangyinqingfei decoction was assessed one, two and four weeks post-irradiation according to the pathological changes and the right lung index (wet weight of right lung/body weight ×100%). Expression levels of matrix metalloproteinase-12 (MMP-12) and tissue inhibitors of metalloproteinases-1 (TIMP-1) in lung tissue were determined using the reverse transcription-polymerase chain reaction and western blot analysis. Pretreatment with Yangyinqingfei resulted in a significant dose-dependent resistance to radiation-induced body weight loss. The expression of MMP-12 and TIMP-1 increased following irradiation. However, the levels of MMP-12 and TIMP-1 in groups receiving Yangyinqingfei were lower four weeks after irradiation compared with those in rats administered saline. Cumulatively, these results suggest that Yangyinqingfei has a protective effect on radiation-induced lung injury in rats, possibly by downregulating MMP-12 and TIMP-1 expression.

Effect of ozone oxidative preconditioning in preventing early radiation-induced lung injury in rats

Ionizing radiation causes its biological effects mainly through oxidative damage induced by reactive oxygen species. Previous studies showed that ozone oxidative preconditioning attenuated pathophysiological events mediated by reactive oxygen species. As inhalation of ozone induces lung injury, the aim of this study was to examine whether ozone oxidative preconditioning potentiates or attenuates the effects of irradiation on the lung. Rats were subjected to total body irradiation, with or without treatment with ozone oxidative preconditioning (0.72 mg/kg). Serum proinflammatory cytokine levels, oxidative damage markers, and histopathological analysis were compared at 6 and 72 h after total body irradiation. Irradiation significantly increased lung malondialdehyde levels as an end-product of lipoperoxidation. Irradiation also significantly decreased lung superoxide dismutase activity, which is an indicator of the generation of oxidative stress and an early protective response to oxidative damage. Ozone oxidative preconditioning plus irradiation significantly decreased malondialdehyde levels and increased the activity of superoxide dismutase, which might indicate protection of the lung from radiation-induced lung injury. Serum tumor necrosis factor alpha and interleukin-1 beta levels, which increased significantly following total body irradiation, were decreased with ozone oxidative preconditioning. Moreover, ozone oxidative preconditioning was able to ameliorate radiation-induced lung injury assessed by histopathological evaluation. In conclusion, ozone oxidative preconditioning, repeated low-dose intraperitoneal administration of ozone, did not exacerbate radiation-induced lung injury, and, on the contrary, it provided protection against radiation-induced lung damage.

Protective effects of caffeic acid phenethyl ester on radiation induced lung injury in rats

The prevention of radiation-induced pulmonary toxicity may help to improve radiation therapy in the cancer patient. The aim of this study was to investigate the pulmonary protective effects of caffeic acid phenethyl ester (CAPE), an antioxidant, on radiation-induced lung injury in rats. 30 Wistar albino rats were divided into three groups and treated with saline, Radiation (RT) and RT + CAPE respectively. All rats were treated with CAPE (50 ?mol/kg i.p.) or saline. The first dose of CAPE was injected 24 h before radiation and application continued daily, with radiation in second day and 2 days more after the radiation treatment. Radiation dose was 800 cGy for total body. At 72 hr after the last radiation application, under general anesthesia using ip ketamine, the lungs were removed immediately after decapitation. After sacrification, antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) activities and malondiadehyde (MDA) levels were evaluated in lung tissue. The level of malondialdehyde (MDA) was higher in the RT group (233.4+/-1.5 nmol/g protein) than in both the control (131.8+/-0.92) and the RT + CAPE (151.4+/-1.8) groups (P < 0.001). However, CAT activity was decreased in the RT group (7.26+/-0.27 U mg protein) compared with control (8.49+/-0.51) and increased again in the RT + CAPE group (8.31+/-0.56; P < 0.001). In accord with CAT activity, SOD activity in the RT group (0.42+/-0.07 nmol MDA/g wet tissue) was different from the control (0.78+/-0.02) and RT + CAPE (0.86+/-0.06) groups (P < 0.001). CAPE application with radiation therapy attenuated radiation induced pulmonary injury in vivo, possibly by its antioxidant effect.

Proton and hyperpolarized helium magnetic resonance imaging of radiation-induced lung injury in rats*1

<h2>Abstract</h2><h3>Purpose</h3> To assess the usefulness of hyperpolarized helium (³He) MRI, including apparent diffusion coefficient measurements, in the detection and evaluation of radiation-induced lung injury in rats. <h3>Methods and materials</h3> Female Fischer-344 rats were treated to the right lung with fractionated dose of 40 Gy (5 × 8 Gy) using 4-MV photons. Conventional proton (¹H) and hyperpolarized (³He) MRI were used to image the lungs 3–6 months after radiation treatment. Apparent diffusion coefficient (ADC) maps of hyperpolarized ³He in the lungs were calculated using a nonlinear, least-squares fitting routine on a pixel-by-pixel basis. After imaging, lungs were processed for histologic assessment of damage. <h3>Results</h3> The effect of radiation was time dependent with progressive right lung damage ranging from mild to moderate at 3 months to severe fibrosis with structural deformation at 6 months after radiation. There was a significant decrease in the apparent diffusion coefficient of hyperpolarized ³He gas in radiation-treated lungs. Areas of decreased ADC in the lungs correlated with fibrosis shown by histology. <h3>Conclusion</h3> This is the first study to show that hyperpolarized ³He MRI can detect radiation-induced lung injury noninvasively. Reduced hyperpolarized ³He ADC values postradiation likely reflect reduced alveolar volumes associated with fibrosis of the interstitium. Future studies at earlier time points may determine whether this noninvasive imaging technique can detect lung damage before clinical symptoms. Development of this new approach of magnetic resonance lung imaging in the rat model of radiation-induced lung injury will increase the ability to develop appropriate algorithms and more accurate models of the normal tissue complication probability.

Proton and hyperpolarized helium magnetic resonance imaging of radiation-induced lung injury in rats

Purpose To assess the usefulness of hyperpolarized helium ( 3He) MRI, including apparent diffusion coefficient measurements, in the detection and evaluation of radiation-induced lung injury in rats. Methods and materials Female Fischer-344 rats were treated to the right lung with fractionated dose of 40 Gy (5 × 8 Gy) using 4-MV photons. Conventional proton ( 1H) and hyperpolarized ( 3He) MRI were used to image the lungs 3–6 months after radiation treatment. Apparent diffusion coefficient (ADC) maps of hyperpolarized 3He in the lungs were calculated using a nonlinear, least-squares fitting routine on a pixel-by-pixel basis. After imaging, lungs were processed for histologic assessment of damage. Results The effect of radiation was time dependent with progressive right lung damage ranging from mild to moderate at 3 months to severe fibrosis with structural deformation at 6 months after radiation. There was a significant decrease in the apparent diffusion coefficient of hyperpolarized 3He gas in radiation-treated lungs. Areas of decreased ADC in the lungs correlated with fibrosis shown by histology. Conclusion This is the first study to show that hyperpolarized 3He MRI can detect radiation-induced lung injury noninvasively. Reduced hyperpolarized 3He ADC values postradiation likely reflect reduced alveolar volumes associated with fibrosis of the interstitium. Future studies at earlier time points may determine whether this noninvasive imaging technique can detect lung damage before clinical symptoms. Development of this new approach of magnetic resonance lung imaging in the rat model of radiation-induced lung injury will increase the ability to develop appropriate algorithms and more accurate models of the normal tissue complication probability.

Expression of Intercellular Adhesion Molecule-1 and Lymphocyte Function-Associated Antigen-1 on Alveolar Macrophages in the Acute Stage of Radiation-Induced Lung Injury in Rats

We investigated the expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) on alveolar macrophages and on lung tissue in the early stage of radiation-induced lung injury. Cells in the bronchoalveolar lavage and lung tissue were obtained from rats at various times between 1 and 8 weeks after 20 Gy of 60Co gamma irradiation of a hemithorax. These specimens were stained immunohistochemically with anti-ICAM-1 and anti-LFA-1alpha monoclonal antibodies. The expression of these factors was compared with that of a control group. The total number of alveolar macrophages in the bronchoalveolar lavage was significantly reduced from 1 to 3 weeks, and the number of neutrophils was significantly increased 2 and 3 weeks after irradiation. ICAM-1 and LFA-1 expression on alveolar macrophages was significantly increased starting 1 week after irradiation. The expression of ICAM-1 and LFA-1 on lung tissue was not elevated up to 8 weeks after irradiation. In conclusion, the increased expression of ICAM-1 and LFA-1 on alveolar macrophages as early as 1 week after irradiation suggests that adhesion molecules play a role in the development of radiation-induced lung injury.