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The intestinal dysbacteriosis is closely associated with the occurrence and progress of radiation-induced intestinal injury. However, the specific mechanism remains unclear. Symbiotic bacteria in the human body play a significant role in maintaining the homeostasis of the intestinal microenvironment while participating in various physiological and pathological processes such as metabolism, immunoregulation, inflammation, and tumorigenesis. Ionizing radiation can destroy the intestinal epithelial barrier, creating an oxidative stress microenvironment. Consequently, the composition and structure of microbiota change, leading to dysbacteriosis through downstream inflammatory factors. Dysbacteriosis can further exacerbate radiation-induced intestinal injury by weakening the resistance of the intestinal epithelial barrier, activating inflammatory signaling pathways, and upregulating radiation-induced apoptosis response. The probiotic supplementation and fecal bacteria transplantation can reduce radiation-induced intestinal injury by regulating the balance of intestinal microbiota. This study reviews the advances in research on the pathogenesis and clinical protection of radiation enteritis based on gut microbiota, in order to provide a theoretical basis and reference for the prevention and treatment of radiation enteritis.
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Radiation protection drugs are often accompanied by toxicity, even amifostine, which has been the dominant radio-protecting drug for nearly 30 years. Furthermore, there is no therapeutic drug for radiation-induced intestinal injury (RIII). This paper intends to find a safe and effective radio-protecting ingredient from natural sources. The radio-protecting effect of Ecliptae Herba (EHE) was discovered preliminarily by antioxidant experiments and the mouse survival rate after 137Cs irradiation. EHE components and blood substances in vivo were identified through UPLC‒Q-TOF. The correlation network of "natural components in EHE-constituents migrating to blood-targets-pathways" was established to predict the active components and pathways. The binding force between potential active components and targets was studied by molecular docking, and the mechanism was further analyzed by Western blotting, cellular thermal shift assay (CETSA), and ChIP. Additionally, the expression levels of Lgr5, Axin2, Ki67, lysozyme, caspase-3, caspase-8,8-OHdG, and p53 in the small intestine of mice were detected. It was found for the first time that EHE is active in radiation protection and that luteolin is the material basis of this protection. Luteolin is a promising candidate for RⅢ. Luteolin can inhibit the p53 signaling pathway and regulate the BAX/BCL2 ratio in the process of apoptosis. Luteolin could also regulate the expression of multitarget proteins related to the same cell cycle.
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Radiation-induced intestinal injury(RIII), a common complication of radiotherapy for pelvic malignancies, affects the quality of life and the radiotherapy efficacy for cancer. Currently, the main clinical approaches for the prevention and treatment of RIII include drug therapy, hyperbaric oxygen therapy, and surgical treatment. Among these methods, drug therapy is cost-effective. Traditional Chinese medicine(TCM) containing a variety of active components demonstrates mild side effects and good efficacy in preventing and treating RIII. Studies have proven that TCM active components, such as flavonoids, terpenoids, phenylpropanoids, and alkaloids, can protect the intestine against RIII by inhibiting oxidative stress, regulating the expression of inflammatory cytokines, modulating the mitochondrial apoptosis pathway, adjusting intestinal flora, and suppressing cell apoptosis. These mechanisms can help alleviate the symptoms of RIII. The paper aims to provide a theoretical reference for the discovery of new drugs for the prevention and treatment of RIII by reviewing the literature on TCM active components in the last 10 years.
Subject(s)
Medicine, Chinese Traditional , Drugs, Chinese Herbal/pharmacology , Quality of Life , Intestines , AlkaloidsABSTRACT
Objective:To elucidate the change of whole genome expression profile for the effect of melatonin on radiation-induced intestinal injury in mice.Methods:C57BL/6J male mice were administrated with melatonin at 10 mg/kg body weight by intraperitoneal injection once a day for five consecutive days before abdominal irradiation with 14 Gy of γ-rays. Small intestines were harvested 3 d after radiation. GO annotation and KEGG pathway of the differential genes involved in small intestine were explored by DNA microarray analysis.Results:Compared with the control group, 584 differential genes were up-regulated and 538 differential genes were down-regulated for administration group pre-irradiation. The overlapping differential genes were selected from the irradiated mice and the administrated mice pre-irradiation. There were 324 up-regulated genes and 246 down-regulated genes unique to the administrated mice pre-irradiation. GO annotation analysis of the differential genes indicated that the top 15 significantly enriched biological processes for the administrated mice pre-irradiation mainly included autophagosome assembly (GO: 0000045), autophagosome organization (GO: 1905037) and regulation of acute inflammatory response (GO: 0002673). The genes ATG12, ATG16L2 and AMBRA1 were involved in autophagosome assembly and autophagosome organization. The genes C3, CPN1, CD55, CFP, CNR1, C1QA, C2 and CREB3L3 were involved in the regulation of acute inflammation response. KEGG pathway analysis of the differential genes involved indicated that the top 15 significantly enriched pathways for the administrated mice pre-irradiation mainly included O-glycan biosynthesis (hsa00512), glycosphingolipid biosynthesis (hsa00603), ECM-receptor interaction (hsa04512) and biosynthesis of unsaturated fatty acids (hsa01040). qRT-PCR verification showed that the expressions of ATG12 and ATG16L2 genes involved in autophagy for the administrated mice pre-irradiation increased significantly compared with the irradiated mice ( t=2.40, 4.35, P<0.05). Conclusions:The differential genes related with the biological process of autophagy, acute inflammatory response and the pathway of unsaturated fatty acid biosynthesis might be involved in the effect of melatonin on radiation-induced intestinal injury.
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Objective:To investigate the effects and mechanisms of copper transporter 1 (CTR1) in radiation induced intestinal injury in vitro. Methods:Human small intestinal epithelial cells (HIEC) were irradiated with 2, 4, 6, 8 Gy of X-rays and rat intestinal epithelial cells (IEC-6) were irradiated with 5, 10, 15, 20 Gy of X-rays. At 2, 4, 8, 24, and 48 h after irradiation, the expression of CTR1 was detected by Western blot assay. In some experiments, HIEC and IEC-6 cells were transfected with CTR1 shRNA and then exposed to X-rays. Copper levels were detected by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The radiosensitivity of cells was verified by colonogenic assay, the cellular reactive oxygen species (ROS) level and DNA damage were detected to further explore the related mechanism. In addition, Western blot was applied to detect the expressions of antioxidants and cuproptosis associated proteins in enterocytes after silencing CTR1 or irradiation.Results:The expression of CTR1 was increased by X-ray irradiation in a dose-dependent manner ( t=3.53, 3.45, 6.37, 11.11, 11.13, P<0.05). CTR1 expression was successfully diminished by CTR1 shRNA adenovirus vectors. According to the survival curves, the enhancement ratios of the radiosensitivity of HIEC and IEC-6 cells with CTR1 knocking-down were 1.146 and 1.201, respectively. Radiation-induced copper accumulation was alleviated after CTR1 silencing in IEC-6 cells ( t=3.10, P<0.05). At 0.5 h after irradiation, the ROS production in the CTR1 knockdown group was significantly lower than that in the control group ( t=5.23, 2.96, P<0.05). At 1 h after irradiation, the protein expression of γ-H2AX in the CTR1 knockdown group was obviously lower than that in the control group ( t=7.50, 4.29, P<0.05). The expressions of Nrf2 and HO-1 were increased after irradiation, which could be further increased after CTR1 silencing. In addition, cuproptosis associated protein DLAT, LIAS and FDX1 were reduced post-irradiation, which were recovered after CTR1 silencing. Conclusions:The radioresistance of HIEC and IEC-6 cells was enhanced after CTR1 silencing, possibly through the intracellular ROS and cuproptosis pathway.
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Objective:To investigate the changes of CPT1A and CPT1B protein expression in rat intestinal epithelial cells (IEC-6) after 60Co γ-ray irradiation, and the mechanism of the influence of carnitine palmitoyltransferase 1 (CPT1) on the proliferation of irradiated IEC-6 cells. Methods:IEC-6 cells were cultured in serum-normal medium or in serum-starved medium overnight, and pretreated with 20 μmol/L palmitic acid (PA) before irradiation with 0, 5, 10, and 15 Gy. At 24 h after irradiation, the cellular protein was collected for the measurement of CPT1A and CPT1B proteins by Western blot. The influences of ETO, an inhibitor of CPT1, on the survival and proliferation of irradiated IEC-6 cells were analyzed by colony formation assay and CCK-8 assay. The protein expressions and phosphorylation levels of the extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK) in 5 Gy irradiated IEC-6 cells pre-treated with ETO were analyzed by Western blot at 48 h after radiation.Results:When IEC-6 cells were cultured in serum-normal medium together with PA, the protein level of CPT1A was significantly increased after 15 Gy irradiation ( t=-2.82, P<0.05). When IEC-6 cells were cultured in serum-starved medium, the protein level of CPT1A was significantly increased at 5, 10, and 15 Gy ( t=-3.28, -8.72, -8.67, P<0.05). When IEC-6 cells were cultured in serum-starved medium together with PA, the protein levels of CPT1A were significantly increased at 5, 10 and 15 Gy ( t=-10.69, -7.02, -8.23, P<0.05), the protein levels of CPT1B were significantly increased at 10 and 15 Gy ( t=-3.73, -5.05, P<0.05). After irradiation, the survival and proliferation of IEC-6 cells in ETO group were significantly lower than those in control group ( t=5.46, 13.22, P<0.05), and the protein level of ERK1/2 and p-JNK in ETO group were significantly lower than those in control group ( t=4.01, 3.29, 10.68, 14.44, P<0.05). Conclusions:CPT1 promoted radiation-induced IEC-6 injury cells survival and proliferation by enhancing the expression level of ERK1/2 protein and the activity of JNK.
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Objective:To study the protective effect of Mongolian medicine Bateri-7 on radiation-induced intestinal injury in mice.Methods:C57BL/6J male mice were randomly divided into control group, irradiation group and irradiation plus drug administration group, with 10 or 15 mice in each group. For irradiation group, the mice were given a single dose of 12 Gy 60Co γ-rays with total body irradiation. For drug treatment, the mice were gavaged with Bateri-7 (530 mg/kg) 7 d before irradiation until 3 d after IR. At 6 h and 24 h after irradiation, the Tunel positive cells in intestine were detected immunohistochemically. At 3.5 d after irradiation, the structure of intestinal villi was observed by HE staining, and the BrdU and Ki67 positive cells were detected immunohistochemically. The expression levels of IL-6, TNF-α and Cxcl-5 were detected by qPCR. The FITC-dextran in peripheral blood was also determined. Results:The survival of irradiated mice was significantly increased by Bateri-7 ( χ2= 5.84, P < 0.05), but there was no significant difference in weight between two groups ( P > 0.05). The villi length of small intestine in the irradiation plus drug group was significantly longer than that in the irradiation group ( t = 20.24, P < 0.05), and there was no significant difference in the depth of intestinal crypt between two groups ( P > 0.05). At 6 and 24 h after irradiation, the number of Tunel positive cells in intestinal crypts in the irradiation plus drug group was significantly reduced in comparison with the irradiation group ( t = 3.52, 2.90, P < 0.05). At 3.5 d after irradiation, the level of FITC-dextran in serum and the expressions of IL-6, TNF-α and Cxcl-5 in small intestine of mice in the irradiation plus drug group were significantly lower than those in the irradiation group, respectively( t = 6.92, 7.01, 7.18, 13.16, P < 0.05). The number of BrdU and Ki67 positive cells in the crypt of mice in the irradiation plus drug group was higher than that of the irradiation group ( t = 3.91, 2.57, P < 0.05). Conclusions:Mongolian medicine Bateri-7 can effectively alleviate irradiation-induced intestinal injury of mice, which may have a good preventive and therapeutic effect on radiation enteritis.
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Gut microbiota not only affects the activity of tryptophan metabolism rate limiting enzymes in intestinal cells, but also cooperatively produces a variety of catalytic enzymes, which directly affects the type and quantity of tryptophan metabolites in the intestine. Multiple tryptophan-associated indole compounds originating from the gut microbiome are significantly decreased in the peripheral blood of mice, and negatively correlated with radiation dose ranging from 2 to 10.4 Gy, which might be biomarkers for acute radiation-induced intestinal injury. Recent studies have reported that indole 3-propionic acid (IPA), indole-3-carboxaldehyde (I3A) and kynurenic acid (KYNA), which are tryptophan catabolites derived from gut microbiota, aryl hydrocarbon receptor, which is one of the receptors for tryptophan catabolites, and inhibition of indoleamine 2,3 dioxygenase-1, which is a main rate-limiting enzyme in intestinal tryptophan catabolism, can protect against radiation-induced intestinal toxicity. A more comprehensive understanding of the dynamics of tryptophan catabolites and their roles in acute radiation-induced intestinal injury is needed to deepen the understanding of the pathogenesis in radiation-induced intestinal injury and exploration of effective diagnostic and therapeutic approaches.
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At present, there is no effective treatment method of radiation-induced intestinal injury. Clinically, only symptomatic remission therapy can be used. Intestinal stem cells (ISCs) have strong renewal ability, which is an important part of intestinal structure regeneration. To promote the recovery of the number and function of ISCs has been a research hotspot in the treatment of radiation gastrointestinal syndrome. This article introduces the important role of ISCs in the protection of radiation-induced intestinal injury and its clinical application significance from the classification and regulatory mechanism of ISCs, and drugs that regulate the damage, apoptosis and repair of stem cells, so as to provide reference for the future research on the role of intestinal stem cells in radiation protection.
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Objective To investigate the dynamic changes of gene expressions in mouse jejunum after lethal dose abdomen irradiation (ABI).Methods RNA was extracted from mouse jejunum at 0 and 6 h,3.5 and 5 d after 14 Gy 137Cs γ-ray ABI and then subjected to RNA-sequence analysis.Gene with expressions changed more than 2-fold of control were identified as differentially expressed ones.The selected genes were subsequently analyzed using IPA,Funrich,GO and KEGG software.Results Gene analysis of mouse jejunum samples showed that radiation activated p53 pathway at 6 h and 3.5 d after ABI.Interaction network analysis of genes suggested that Lck,Cdkl and Fyn,genes could play an important role in jejunum damage at 3.5 d after ABI.The gene expression profiles demonstrated that ABI up-regulated DNA damage repair pathways and down-regulated cell adhesion molecules,focal adhesion and IgA production pathways.Conclusions The p53 signaling pathway and some key genes such as Lck,Cdkl,and Fyn may contribute to the radiation-induced intestinal injury.
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Objective To investigate the reliable methods for establishing models of acute radiation enteritis (ARE) and the criteria used to judge whether the model is successfully established.Methods A total of 98 rats were randomly divided into normal control group (group A),fractionated dose group B (4 Gy/fraction for 3 fractions),fractionated dose group C (4 Gy/fraction for 4 fractions),fractionated dose group D (4 Gy/fraction for 5 fractions),single fraction group E (12 Gy in a single fraction),single fraction group F (16 Gy in a single fraction),and single fraction group G (20 Gy in a single fraction).Abdominal irradiation was performed for all rats,and the changes in body weight and defecation were observed.Magnetic resonance imaging (MRI) was performed on days 3-5 after irradiation,and on the 4th day,anatomy was performed to measure the length of small intestine with edema,blood samples were collected to measure endotoxins,and the specimens of small intestine were collected to observe pathological changes.The independent-samples t-test was used for comparison between groups.Results After irradiation,groups D,E,F,and G experienced varying degrees of diarrhea and had positive results from endotoxins test.Group D had a longer length of small intestine with edema than group C (P=0.00) and had a similar length as group E (P=0.46).Groups E,F,and G showed dilation and dropsy in the intestinal canal on MRI,and groups F and G showed patchy signals of dropsy in the abdominal cavity.Groups F and G showed varying degrees of necrosis in the small intestine and died within 14 days after irradiation.Conclusions When the radiation dose is 33-46 Gy (biologically equivalent dose),both single dose and fractionated dose can successfully establish the model of ARE,while fractionated dose can be better controlled.
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Objective To assess the therapeutic effect of human adipose-derived mesenchymal stem cells on radiation-induced vascular injury in the small intestine of rat. Methods A total of 34 male Sprague-Dawley rats were enrolled in this study. To establish a model of radiation-induced intestinal injury, each rat was irradiated with 15 Gy in whole abdomen. 17 rats were randomly selected and infused intraperitoneally with passage 6 ( P6 ) Ad-MSCs, and the other 17 rats that received PBS were set as control. 10 days post-irradiation, the number of CD31+ endothelial cells in the small intestine villus was measured by flow-cytometry, the expressions of CD31, CD105 and isolectin-B4 in the na?ve endothelial cells with detected by IHC-staining, and the vascular integrity was evaluated by measuring VE-Cadherin. The origination of na?ve endothelial cells within injured intestine was also analyzed. In addition, total mRNA were extracted from irradiated small intestine to assay the expressions of VEGF, bFGF, Flk-1 and SDF-1 using quantitative Real-time PCR. Results Compared to the control, the amount of CD31-postive endothelial cells within irradiated intestine was significantly increased after Ad-MSCs infusion ( t=12?15, P<0?05). The microvascular density in the injured sites was also significantly increased by the infusion of Ad-MSCs (20 d:t=10?33, P<0. 05;30 d:t=32?85, P<0?05). Moreover, the expressions of VEGF, bFGF, Flk-1 and SDF-1 were significantly up-regulated after delivery of Ad-MSCs ( VEGF:t =10?34, bFGF:t=11?25,Flk-1:t=6?73, SDF-1:t=6?73, all P<0?05), which was beneficial in maintaining the integrity of intra-villus blood-vessels as well as promoting neovascularization in the injured sites. Conclusion Ad-MSCs had potentials in healing radiation-induced vascular injury in rat small intestine.