Protective Effects and Mechanisms of Huangqi Decoction Against Radiation-Induced Bystander Effects / Efectos Protectores y Mecanismos de la Decocción de Huangqi Contra los Efectos Secundarios Inducidos por la Radiación

SUMMARY: The 12C6+ heavy ion beam irradiation can cause bystander effects. The inflammatory cytokines, endocrine hormones and apoptotic proteins may be involved in 12C6+ irradiation-induced bystander effects. This study characterized the protective effects and mechanisms of Huangqi decoction (HQD) against 12C6+ radiation induced bystander effects. Wistar rats were randomly divided into control, 12C6+ heavy ion irradiation model, and high-dose/medium-dose/low-dose HQD groups. HE staining assessed the pathological changes of brain and kidney. Peripheral blood chemical indicators as well as inflammatory factors and endocrine hormones were detected. Apoptosis was measured with TUNEL. Proliferating cell nuclear antigen (PCNA) expression was determined with real-time PCR and Western blot.Irradiation induced pathological damage to the brain and kidney tissues. After irradiation, the numbers of white blood cells (WBC) and monocyte, and the expression of interleukin (IL)-2, corticotropin-releasing hormone (CRH) and PCNA decreased. The damage was accompanied by increased expression of IL-1β, IL-6, corticosterone (CORT) and adrenocorticotropic hormone (ACTH) as well as increased neuronal apoptosis. These effects were indicative of radiation-induced bystander effects. Administration of HQD attenuated the pathological damage to brain and kidney tissues, and increased the numbers of WBC, neutrophils, lymphocyte and monocytes, as well as the expression of IL-2, CRH and PCNA. It also decreased the expression of IL-1β, IL-6, CORT and ACTH as well as neuronal apoptosis. HQD exhibits protective effects against 12C6+ radiation-induced bystander effects. The underlying mechanism may involve the promotion of the production of peripheral blood cells, inhibition of inflammatory factors and apoptosis, and regulation of endocrine hormones.

La irradiación con haz de iones pesados 12C6+ puede provocar efectos secundarios. Las citoquinas inflamatorias, las hormonas endocrinas y las proteínas apoptóticas pueden estar involucradas en los efectos secundarios inducidos por la irradiación 12C6+. Este estudio caracterizó los efectos y mecanismos protectores de la decocción de Huangqi (HQD) contra los efectos externos inducidos por la radiación 12C6+. Las ratas Wistar se dividieron aleatoriamente en grupos control, modelo de irradiación de iones pesados 12C6+ y grupos de dosis alta/media/baja de HQD. La tinción con HE evaluó los cambios patológicos del cerebro y el riñón. Se detectaron indicadores químicos de sangre periférica, así como factores inflamatorios y hormonas endocrinas. La apoptosis se midió con TUNEL. La expresión del antígeno nuclear de células en proliferación (PCNA) se determinó mediante PCR en tiempo real y transferencia Western blot. La irradiación indujo daños patológicos en los tejidos cerebrales y renales. Después de la irradiación, disminuyó el número de glóbulos blancos (WBC) y monocitos, y la expresión de interleucina (IL)-2, hormona liberadora de corticotropina (CRH) y PCNA. El daño estuvo acompañado por una mayor expresión de IL-1β, IL-6, corticosterona (CORT) y hormona adrenocorticotrópica (ACTH), así como un aumento de la apoptosis neuronal. Estas alteraciones fueron indicativas de efectos inducidos por la radiación. La administración de HQD atenuó el daño patológico a los tejidos cerebrales y renales, y aumentó el número de leucocitos y monocitos, así como la expresión de IL-2, CRH y PCNA. También disminuyó la expresión de IL-1β, IL-6, CORT y ACTH, así como la apoptosis neuronal. HQD exhibe mecanismos protectores contra los efectos externos inducidos por la radiación 12C6+. El mecanismo subyacente puede implicar la promoción de la producción de células sanguíneas periféricas, la inhibición de factores inflamatorios y la apoptosis y la regulación de hormonas endocrinas.

Cytosine-phosphate-guanine oligodeoxynucleotides alleviate radiation-induced kidney injury in cervical cancer by inhibiting DNA damage and oxidative stress through blockade of PARP1/XRCC1 axis.

BACKGROUND: Radiotherapy can cause kidney injury in patients with cervical cancer. This study aims to investigate the possible molecular mechanisms by which CpG-ODNs (Cytosine phosphate guanine-oligodeoxynucleotides) regulate the PARP1 (poly (ADP-ribose) polymerase 1)/XRCC1 (X-ray repair cross-complementing 1) signaling axis and its impact on radiation kidney injury (RKI) in cervical cancer radiotherapy. METHODS: The GSE90627 dataset related to cervical cancer RKI was obtained from the Gene Expression Omnibus (GEO) database. Bioinformatics databases and R software packages were used to analyze the target genes regulated by CpG-ODNs. A mouse model of RKI was established by subjecting C57BL/6JNifdc mice to X-ray irradiation. Serum blood urea nitrogen (BUN) and creatinine levels were measured using an automated biochemical analyzer. Renal tissue morphology was observed through HE staining, while TUNEL staining was performed to detect apoptosis in renal tubular cells. ELISA was conducted to measure levels of oxidative stress-related factors in mouse serum and cell supernatant. An in vitro cell model of RKI was established using X-ray irradiation on HK-2 cells for mechanism validation. RT-qPCR was performed to determine the relative expression of PARP1 mRNA. Cell proliferation activity was assessed using the CCK-8 assay, and Caspase 3 activity was measured in HK-2 cells. Immunofluorescence was used to determine γH2AX expression. RESULTS: Bioinformatics analysis revealed that the downstream targets regulated by CpG-ODNs in cervical cancer RKI were primarily PARP1 and XRCC1. CpG-ODNs may alleviate RKI by inhibiting DNA damage and oxidative stress levels. This resulted in significantly decreased levels of BUN and creatinine in RKI mice, as well as reduced renal tubular and glomerular damage, lower apoptosis rate, decreased DNA damage index (8-OHdG), and increased levels of antioxidant factors associated with oxidative stress (SOD, CAT, GSH, GPx). Among the CpG-ODNs, CpG-ODN2006 had a more pronounced effect. CpG-ODNs mediated the inhibition of PARP1, thereby suppressing DNA damage and oxidative stress response in vitro in HK-2 cells. Additionally, PARP1 promoted the formation of the PARP1 and XRCC1 complex by recruiting XRCC1, which in turn facilitated DNA damage and oxidative stress response in renal tubular cells. Overexpression of either PARP1 or XRCC1 reversed the inhibitory effects of CpG-ODN2006 on DNA damage and oxidative stress in the HK-2 cell model and RKI mouse model. CONCLUSION: CpG-ODNs may mitigate cervical cancer RKI by blocking the activation of the PARP1/XRCC1 signaling axis, inhibiting DNA damage and oxidative stress response in renal tubule epithelial cells.

Modeling normal bladder injury after radiation therapy.

PURPOSE: For decades, Dr. John Moulder has been a leading radiation biologist and one of the few who consistently supported the study of normal tissue responses to radiation. His meticulous modeling and collaborations across the field have offered a prime example of how research can be taken from the bench to the bedside and back, with the ultimate goal of providing benefit to patients. Much of the focus of John's work was on mitigating damage to the kidney, whether as the result of accidental or deliberate clinical exposures. Following in his footsteps, we offer here a brief overview of work conducted in the field of radiation-induced bladder injury. We then describe our own preclinical experimental studies which originated as a response to reports from a clinical genome-wide association study (GWAS) investigating genomic biomarkers of normal tissue toxicity in prostate cancer patients treated with radiotherapy. In particular, we discuss the use of Renin-Angiotensin System (RAS) inhibitors as modulators of injury, agents championed by the Moulder group, and how RAS inhibitors are associated with a reduction in some measures of toxicity. Using a murine model, along with precise CT-image guided irradiation of the bladder using single and fractionated dosing regimens, we have been able to demonstrate radiation-induced functional injury to the bladder and mitigation of this functional damage by an inhibitor of angiotensin-converting enzyme targeting the RAS, an experimental approach akin to that used by the Moulder group. We consider our scientific trajectory as a bedside-to-bench approach because the observation was made clinically and investigated in a preclinical model; this experimental approach aligns with the exemplary career of Dr. John Moulder. CONCLUSIONS: Despite the differences in functional endpoints, recent findings indicate a commonality between bladder late effects and the work in kidney pioneered by Dr. John Moulder. We offer evidence that targeting the RAS pathway may provide a targetable pathway to reducing late bladder toxicity.

Splenic, hepatic, renal and pulmonary clearance dysfunction associated with high-energy X-rays.

PURPOSE: To verify the high-energy X-rays effects on the blood clearance of colloidal particles by the spleen, liver, kidneys, and lungs. MATERIALS AND METHODS: Seventeen male Wistar rats were distributed into three groups. Group 1 (n = 5) - control - non-irradiated animals, group 2 (n = 6) - irradiated animals studied 24 h after irradiation, and group 3 (n = 6) - irradiated animals studied 48 h after irradiation. The animals were anesthetized and irradiated with a non-fractionated 8 Gy dose in the abdominal region divided into two parallel and opposite fields, 4 Gy was given to the anteroposterior and 4 Gy to the posteroanterior. This high dose of high-energy X-rays causes extensive cell killing, tissue disorganization and break down cell to cell communication. According to the groups, 50 µCi of technetium-phytate were injected into the right internal jugular vein. After 30 minutes, the liver, spleen, kidneys, and lungs were removed. The clot was harvested from the abdominal cavity two minutes after the sectioning of the abdominal aorta and cava vein. The organs and clot were placed into plastic flasks to be weighed and studied for the emission of radioactivity in a gamma radiation detector. The uptake function of each organ was calculated based on the count of gamma rays emitted per minute and normalized with the organ mass, having as a reference the radioactivity count of a standard sample. The arithmetic mean of each organ uptake was calculated and compared among the groups. RESULTS: After irradiation, the spleen uptake of colloidal radiopharmaceutical was greater, while the hepatic, renal, and pulmonary uptake were lower. The renal uptake decreased slower than the hepatic and pulmonary uptake. CONCLUSIONS: A single high dose of high-energy X-rays enhances the splenic clearance function, while it reduces the hepatic, renal, and pulmonary clearance until 48 h after irradiation, with a rapid deterioration of the hepatic and pulmonary uptake function.

Impact of Renal Function on S-1 + Radiotherapy for Locally Advanced Pancreatic Cancer: An Integrated Analysis of Data From 2 Clinical Trials.

OBJECTIVES: S-1 monotherapy with concurrent radiotherapy (RT) is a standard of care for patients with locally advanced pancreatic cancer (LAPC). Although renal dysfunction increases S-1 monotherapy toxicity, its effect in S-1 with concurrent RT remains unknown. We evaluated the effect of renal function on the safety of S-1 with RT for LAPC. METHODS: We performed an integrated exploratory post hoc analysis of data from 2 prospective studies (JCOG1106 and LAPC-S1RT), where patients with LAPC received RT (50.4 Gy/28 fraction for 5.5 weeks) and concurrent S-1 (40 mg/m2 per dose, twice daily on the day of irradiation). We split the patients into high creatinine clearance (CCr; ≥80 mL/min) and low CCr (<80 mL/min) groups and compared the findings to determine treatment safety. RESULTS: The high and low CCr groups showed a median of 97.5 (range, 80.0-194.6) and 64.4 (range, 50.0-78.3) mL/min, respectively. The low CCr group presented more adverse reactions (ARs) of grade 3 or higher and gastrointestinal ARs of grade 2 or higher than the high CCr group (30.8% vs 15.8% and 51.9% vs 36.8%). CONCLUSIONS: The incidence of ARs associated with concurrent S-1 and RT increases in patients with low CCr; therefore, ARs should be duly considered in such patients.

Acute Proteomic Changes in Non-human Primate Kidney after Partial-body Radiation with Minimal Bone Marrow Sparing.

ABSTRACT: Near total body exposure to high-dose ionizing radiation results in organ-specific sequelae, including acute radiation syndromes and delayed effects of acute radiation exposure. Among these sequelae are acute kidney injury and chronic kidney injury. Reports that neither oxidative stress nor inflammation are dominant mechanisms defining radiation nephropathy inspired an unbiased, discovery-based proteomic interrogation in order to identify mechanistic pathways of injury. We quantitatively profiled the proteome of kidney from non-human primates following 12 Gy partial body irradiation with 2.5% bone marrow sparing over a time period of 3 wk. Kidney was analyzed by liquid chromatography-tandem mass spectrometry. Out of the 3,432 unique proteins that were identified, we found that 265 proteins showed significant and consistent responses across at least three time points post-irradiation, of which 230 proteins showed strong upregulation while 35 proteins showed downregulation. Bioinformatics analysis revealed significant pathway and upstream regulator perturbations post-high dose irradiation and shed light on underlying mechanisms of radiation damage. These data will be useful for a greater understanding of the molecular mechanisms of injury in well-characterized animal models of partial body irradiation with minimal bone marrow sparing. These data may be potentially useful in the future development of medical countermeasures.

Roles of Simvastatin and Sildenafil in Modulation of Cranial Irradiation-Induced Bystander Multiple Organs Injury in Rats.

In radiobiology and radiation oncology fields, the observation of a phenomenon called radiation-induced bystander effect (RIBE) has introduced the prospect of remotely located tissues' affection. This phenomenon has been broadly developed to involve the concept of RIBE, which are relevant to the radiation-induced response of a distant tissue other than the irradiated one. The current study aimed at investigating each of the RIBE of cranial irradiation on oxidative and inflammatory status in different organs such as liver, kidney, heart, lung, and spleen. Being a vital target of the cholinergic anti-inflammatory response to an inflammatory stimulus, the splenic α-7-nicotinic acetylcholine receptor (α-7nAchR) was evaluated and the hepatic contents of thioredoxin, peroxisome proliferator-activated receptor-alpha and paraoxinase-1 (Trx/PPAR-α/PON) were also assessed as indicators for the liver oxidative stress and inflammatory responses. Being reported to act as antioxidant and anti-inflammatory agents, simvastatin (SV) and/or sildenafil (SD) were investigated for their effects against RIBE on these organs. These objectives were achieved via the biochemical assessments and the histopathological tissues examinations. Five experimental groups, one sham irradiated and four irradiated groups, were exposed to cranial irradiation at dose level of 25 Gy using an experimental irradiator with a Cobalt (Co60) source, RIBE, RIBE + SV (20 mg.(kg.bw)-1 day-1), RIBE + SD (75 mg.(kg.bw)-1 day-1), and RIBE + SV + SD. Cranial irradiation induced structural, biochemical, and functional dys-regulations in non-targeted organs. RIBE-induced organs' injuries have been significantly corrected by the administration of SV and/or SD. Our results suggest the possibility of a potentiated interaction between SV and SD in the modulation of the RIBE associated with head and neck radiotherapy.

Radon inhalation decreases DNA damage induced by oxidative stress in mouse organs via the activation of antioxidative functions.

Radon inhalation decreases the level of lipid peroxide (LPO); this is attributed to the activation of antioxidative functions. This activation contributes to the beneficial effects of radon therapy, but there are no studies on the risks of radon therapy, such as DNA damage. We evaluated the effect of radon inhalation on DNA damage caused by oxidative stress and explored the underlying mechanisms. Mice were exposed to radon inhalation at concentrations of 2 or 20 kBq/m3 (for one, three, or 10 days). The 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels decreased in the brains of mice that inhaled 20 kBq/m3 radon for three days and in the kidneys of mice that inhaled 2 or 20 kBq/m3 radon for one, three or 10 days. The 8-OHdG levels in the small intestine decreased by approximately 20-40% (2 kBq/m3 for three days or 20 kBq/m3 for one, three or 10 days), but there were no significant differences in the 8-OHdG levels between mice that inhaled a sham treatment and those that inhaled radon. There was no significant change in the levels of 8-oxoguanine DNA glycosylase, which plays an important role in DNA repair. However, the level of Mn-superoxide dismutase (SOD) increased by 15-60% and 15-45% in the small intestine and kidney, respectively, following radon inhalation. These results suggest that Mn-SOD probably plays an important role in the inhibition of oxidative DNA damage.

Renal and Red Marrow Dosimetry in Peptide Receptor Radionuclide Therapy: 20 Years of History and Ahead.

The development of dosimetry and studies in peptide receptor radionuclide therapy (PRRT) over the past two decades are reviewed. Differences in kidney and bone marrow toxicity reported between 90Y, 177Lu and external beam radiotherapy (EBRT) are discussed with regard to the physical properties of these beta emitter radionuclides. The impact of these properties on the response to small and large tumors is also considered. Capacities of the imaging modalities to assess the dosimetry to target tissues are evaluated. Studies published in the past two years that confirm a red marrow uptake in 177Lu-DOTATATE therapy, as already observed 20 years ago in 86Y-DOTATOC PET studies, are analyzed in light of the recent developments in the transferrin transport mechanism. The review enlightens the importance (i) of using state-of-the-art imaging modalities, (ii) of individualizing the activity to be injected with regard to the huge tissue uptake variability observed between patients, (iii) of challenging the currently used but inappropriate blood-based red marrow dosimetry and (iv) of considering individual tandem therapy. Last, a smart individually optimized tandem therapy taking benefit of the bi-orthogonal toxicity-response pattern of 177Lu-DOTATATE and of 90Y-DOTATOC is proposed.

Molecular Changes in miRNA in Irradiated Rat Kidneys: Role of miR-34a and its Vascular Targets in the Notch Pathway.

The mechanism(s) of vascular regression in adult organs remains an unexplored gap. Irradiation to the kidney results in vascular regression and renal failure. The goal of this work was to determine molecular mechanism(s) of radiation-induced vascular regression and its mitigation by the drug lisinopril. Female WAG/RijCmcr rats received either 13 Gy X-ray irradiation, sparing one leg, or no irradiation, the latter serving as age-matched controls. Some irradiated animals received lisinopril. Kidney miRNA-seq was performed 35 days postirradiation, before symptoms of nephropathy. MicroRNA expression profiles were compared with data from humans. MicroRNA targets were predicted using TargetScan and confirmed by qRT-PCR and Western blot. Renal vascular endothelial cell density was evaluated at 100 days to confirm vascular regression. The normal rat kidney microRNA profile resembled that of humans. MiR-34a was increased >7-fold and emerged as the predominant rat microRNA altered by radiation. Expression of Jagged1, a ligand in the Notch pathway of vascular development and a target of miR-34a-5p was decreased by radiation but not in irradiated rats receiving lisinopril. Radiation decreased endothelial cells in the kidneys at 100 days, confirming vascular regression. In conclusion, the results of this study showed that radiation greatly increased miRNA34-a in rat kidneys, while lisinopril mitigated radiation-induced decrease of the Notch ligand, Jagged1, a molecular target of miRNA34-a.

Piceatannol promotes hepatic and renal AMPK/SIRT1/PGC-1α mitochondrial pathway in rats exposed to reserpine or gamma-radiation.

Human exposure to radio-therapeutic doses of gamma rays can produce late effects, which negatively affect cancer patients' quality of life, work prospects, and general health. This study was performed to explore the role of Piceatannol (PIC) in the process of "mitochondrial biogenesis" signaling pathway as possible management of disturbances induced in stressed animal model(s) either by gamma-irradiation (IR) or administration of reserpine (RES); as a mitochondrial complex-I inhibitor. PIC (10 mg/kg BW/day; orally) were given to rats for 7 days, after exposure to an acute dose of γ-radiation (6 Gy), or after a single reserpine injection (1 g/kg BW; sc). Compared to reserpine or γ-radiation, PIC has attenuated hepatic and renal mitochondrial oxidative stress denoted by the significant reduction in the content of lipid peroxides and NO with significant induction of SOD, CAT, GSH-PX, and GR activities. PIC has also significantly alleviated the increase of the inflammatory markers, TNF-α and IL-6 and apoptotic markers, cytochrome c, and caspase-3. The decrease of oxidative stress, inflammation, and apoptotic responses were linked to a significant amelioration in mitochondrial biogenesis demonstrated by the increased expression and proteins' tissue contents of SIRT1/p38-AMPK, PGC-1α signaling pathway. The results are substantiated by the significant amelioration in mitochondrial function verified by the higher levels of ATP content, and complex I activity, besides the improvement of hepatic and renal functions. Additionally, histopathological examinations of hepatic and renal tissues showed that PIC has modulated tissue architecture after reserpine or gamma-radiation-induced tissue damage. Piceatannol improves mitochondrial functions by regulating the oxidant/antioxidant disequilibrium, the inflammatory and apoptotic responses, suggesting its possible use as adjuvant therapy in radio-therapeutic protocols to attenuate hepatic and renal injuries.

Effects of Nigella sativa oil and thymoquinone on radiation-induced oxidative stress in kidney tissue of rats.

Ionizing radiation leads to release of free radicals into the systemic circulation from irradiated tissues. These free radicals cause oxidative stress in distant organs. Oxidative status may be reversed by naturally occurring antioxidant agents. The aim of this study was to investigate protective and antioxidant effects of Nigella sativa oil (NSO) and thymoquinone (TQ) in kidney tissue of rats exposed to cranial irradiation. Forty-eight Sprague-Dawley rats were divided into six groups: IR group received irradiation (IR) to total cranium plus saline; IR plus NSO group received IR and NSO; IR plus TQ group received IR and TQ; sham group did not receive NSO, TQ or IR; control group of TQ received dimethyl sulfoxide; control group of NSO received saline. Total oxidant status (TOS), oxidative stress index (OSI) and lipid hydroperoxide (LOOH) levels were studied as oxidative parameters, and total antioxidant status (TAS), total sulfhydryl levels, paraoxonase (PON), ceruloplasmin (Cp) and arylesterase activities were determined as antioxidative parameters in the kidney tissue of rats. Kidney TOS, OSI and LOOH levels were significantly lower in IR plus TQ, IR plus NSO and sham groups compared to IR group (p < 0.001). TAS, PON and Cp activities in IR group were significantly lower compared to the control group (p < 0.001). PON and Cp activities were significantly higher in IR plus NSO and IR plus TQ groups compared to IR group (p < 0.001). In conclusion, free radicals generated by cranial ionizing radiation exposure cause oxidative stress in kidney. NSO and TQ exhibit protective and antioxidant effects against oxidative damage in rats.

Fucoxanthin alters the apelin-13/APJ pathway in certain organs of γ-irradiated mice.

Apelin-13 and APJ are implicated in different key physiological processes. This work aims at exploring the radioprotective effect of fucoxanthin (FX) on γ-radiation (RAD)-induced changes in the apelin-13/APJ pathway, which causes damage in the liver, kidney, lung and spleen of mice. Mice were administered FX (10 mg kg-1 day-1, i.p) and exposed to γ-radiation (2.5 Gy week-1) for four consecutive weeks. The treatment of irradiated mice by FX resulted in a significant amendment in protein expression of the apelin-13/APJ/NF-κB signalling pathway concurrently with reduced hypoxia (hypoxia-inducible factor-1α), suppressed oxidative stress marker (malondialdehyde), enhanced antioxidant defence mechanisms (reduced glutathione and glutathione peroxidase), a modulated inflammatory response [interleukin-6 (IL-6), monocyte chemoattractant protein-1, IL-10 and α-7-nicotinic acetylcholine receptor) and ameliorated angiogenic regulators [matrix metalloproteinase (MMP-2), MMP-9 and tissue inhibitor of metalloproteinase-1), as well as the tissue damage indicator (lactate dehydrogenase) in organ tissues. In addition, there were significant improvement in serum inflammatory markers tumour necrosis factor-α, IL-10, IL-1ß and C-reactive protein compared with irradiated mice. The histopathological investigation of the FX + RAD organ tissues support the biochemical findings where the improvements in the tissues' architecture were obvious when compared with those of RAD. FX was thus shown to have a noticeable radioprotective action mediated through its regulatory effect on the apelin-13/APJ/NF-κB signalling pathway attributed to its antioxidant and anti-inflammatory activity that was reflected in different physiological processes. It could be recommended to use FX in cases of radiation exposure to protect normal tissues.

The efficacy of bone marrow-derived mesenchymal stem cells and/or erythropoietin in ameliorating kidney damage in gamma irradiated rats: Role of non-hematopoietic erythropoietin anti-apoptotic signaling.

Radiation-induced multiple organ injury, including γ-radiation nephropathy, is the most common. Even with dose fractionation strategy, residual late side effects are inevitable. Bone marrow-derived mesenchymal stem cells (BM-MSCs) transplantation and erythropoietin (EPO) have shown to be effective in treating chronic kidney disease and associated anemia. This study aimed to evaluate the effect of BM-MSCs and/or EPO in fractionated γ-irradiation induced kidney damage in rats. Adult male Wistar rats were randomized into 2 groups; normal and 8 Gy (fractionated dose of 2 Gy for 4 days) γ-irradiated rats. Animal from both groups were subdivided to receive the following treatments: BM-MSCs (1 × 106 cells/rat, i.v - once), EPO (100 IU/kg, i.p - every other day for 30 days) or their combined treatment (BM-MSCs and EPO). γ-Irradiated rats showed a noticeable elevation in serum urea and creatinine, kidney malondialdehyde (MDA) and caspase 3 activity. They also revealed significant drop in kidney glutathione (GSH) and Bcl2 protein contents. Conspicuously, they revealed down-regulation of renal EPO signaling (EPO, EPOR, pJAK2, pPI3K and pAkt). Conversely, groups treated with BM-MSCs and/or EPO revealed significant modulation in most tested parameters and appeared to be effective in minimizing the hazard effects of radiation. In conclusion, BM-MSCs and/or EPO exhibited therapeutic potentials against nephrotoxicity induced by fractionated dose of γ-irradiation. An effect mediated by antioxidant and non-hematopoietic EPO downstream anti-apoptotic signaling (PI3K/Akt) pathway. EPO potentiate the repair capabilities of BM-MSCs making this combined treatment a promising therapeutic strategy to overcome radiotherapy-induced kidney damage.

Radiation-induced kidney toxicity: molecular and cellular pathogenesis.

Radiation nephropathy (RN) is a kidney injury induced by ionizing radiation. In a clinical setting, ionizing radiation is used in radiotherapy (RT). The use and the intensity of radiation therapy is limited by normal-tissue damage including kidney toxicity. Different thresholds for kidney toxicity exist for different entities of RT. Histopathologic features of RN include vascular, glomerular and tubulointerstitial damage. The different molecular and cellular pathomechanisms involved in RN are not fully understood. Ionizing radiation causes double-stranded breaks in the DNA, followed by cell death including apoptosis and necrosis of renal endothelial, tubular and glomerular cells. Especially in the latent phase of RN oxidative stress and inflammation have been proposed as putative pathomechanisms, but so far no clear evidence was found. Cellular senescence, activation of the renin-angiotensin-aldosterone-system and vascular dysfunction might contribute to RN, but only limited data is available. Several signalling pathways have been identified in animal models of RN and different approaches to mitigate RN have been investigated. Drugs that attenuate cell death and inflammation or reduce oxidative stress and renal fibrosis were tested. Renin-angiotensin-aldosterone-system blockade, anti-apoptotic drugs, statins, and antioxidants have been shown to reduce the severity of RN. These results provide a rationale for the development of new strategies to prevent or reduce radiation-induced kidney toxicity.

Noninvasive assessment of radiation-induced renal injury in mice.

PURPOSE: The kidney is a radiosensitive late-responding normal tissue. Injury is characterized by radiation nephropathy and decline of glomerular filtration rate (GFR). The current study aimed to compare two rapid and cost-effective methodologies of assessing GFR against more conventional biomarker measurements. METHODS: C57BL/6 mice were treated with bilateral focal X-irradiation (1x14Gy or 5x6Gy). Functional measurements of kidney injury were assessed 20 weeks post-treatment. GFR was estimated using a transcutaneous measurement of fluorescein-isothiocyanate conjugated (FITC)-sinistrin renal excretion and also dynamic contrast-enhanced CT imaging with a contrast agent (ISOVUE-300 Iopamidol). RESULTS: Hematoxylin and eosin (H&E) and Periodic acid-Schiff staining identified comparable radiation-induced glomerular atrophy and mesangial matrix accumulation after both radiation schedules, respectively, although the fractionated regimen resulted in less diffuse tubulointerstitial fibrosis. Albumin-to-creatinine ratios (ACR) increased after irradiation (1x14Gy: 100.4 ± 12.2 µg/mg; 6x5Gy: 80.4 ± 3.02 µg/mg) and were double that of nontreated controls (44.9 ± 3.64 µg/mg). GFR defined by both techniques was negatively correlated with BUN, mesangial expansion score, and serum creatinine. The FITC-sinistrin transcutaneous method was more rapid and can be used to assess GFR in conscious animals, dynamic contrast-enhanced CT imaging technique was equally safe and effective. CONCLUSION: This study demonstrated that GFR measured by dynamic contrast-enhanced CT imaging is safe and effective compared to transcutaneous methodology to estimate kidney function.

Effect of Long-Term Light Deprivation on α-Tocopherol Content in Rats during Ontogeny.

We studied the effect of long-term light deprivation which began at different stages of ontogeny on the content of α-tocopherol in rats during the first 3 months of postnatal development. In the offspring postnatally exposed to constant darkness, the level of α-tocopherol in the liver, kidneys, heart, skeletal muscles, and lungs was significantly decreased at the early stages of postnatal ontogeny (2 weeks and 1 month). In rats kept under constant darkness after birth, the content of α-tocopherol in the lungs was also reduced at the age of 1 month. The modulating effect of light deprivation on the level of α-tocopherol can be associated both with the impact of disturbed circadian rhythms and with increased content of melatonin in the body.

Acute skin exposure to ultraviolet light triggers neutrophil-mediated kidney inflammation.

Photosensitivity to ultraviolet (UV) light affects up to ∼80% of lupus patients. Sunlight exposure can exacerbate local as well as systemic manifestations of lupus, including nephritis, by mechanisms that are poorly understood. Here, we report that acute skin exposure to UV light triggers a neutrophil-dependent injury response in the kidney characterized by upregulated expression of endothelial adhesion molecules as well as inflammatory and injury markers associated with transient proteinuria. We showed that UV light stimulates neutrophil migration not only to the skin but also to the kidney in an IL-17A-dependent manner. Using a photoactivatable lineage tracing approach, we observed that a subset of neutrophils found in the kidney had transited through UV light-exposed skin, suggesting reverse transmigration. Besides being required for the renal induction of genes encoding mediators of inflammation (vcam-1, s100A9, and Il-1b) and injury (lipocalin-2 and kim-1), neutrophils significantly contributed to the kidney type I interferon signature triggered by UV light. Together, these findings demonstrate that neutrophils mediate subclinical renal inflammation and injury following skin exposure to UV light. Of interest, patients with lupus have subpopulations of blood neutrophils and low-density granulocytes with similar phenotypes to reverse transmigrating neutrophils observed in the mice post-UV exposure, suggesting that these cells could have transmigrated from inflamed tissue, such as the skin.

Assessment of Gadobutrol Safety in Combination with Ionizing Radiation Using a Preclinical MRI-Guided Radiotherapy Model.

MR-linac technology enhances the precision of therapeutic radiation by clarifying the tumor-normal tissue interface and provides the potential for adaptive treatment planning. Accurate delineation of tumors on diagnostic magnetic resonance imaging (MRI) frequently requires gadolinium-based contrast agents (GBCAs). Despite generally being considered safe, previous literature suggests that GBCAs are capable of contrast-induced acute kidney injury (AKI). It is unclear if the risk for AKI is enhanced when GBCAs are administered concurrently with ionizing radiotherapy. During irradiation, gadolinium may be liberated from its chelator which may induce AKI. The goal of this work was to determine if radiation combined with GBCAs increased the incidence of AKI. Using a preclinical MRI-guided irradiation system, where MRI acquisitions and radiation delivery are performed in rapid succession, tumor-bearing mice with normal kidney function were injected with GBCA and treated with 2, 8 or 18 Gy irradiation. Renal function was assessed on days three and seven postirradiation to assess for AKI. No clinically relevant changes in blood urea nitrogen and creatinine were observed in any combination of GBCA and radiation dose. From these data, we conclude that GBCA in combination with radiation does not increase the risk for AKI in mice. Additional investigation of multiple doses of GBCA administered concurrently with irradiation is warranted to evaluate the risk of chronic kidney injury.

Gender differences in UV-induced skin inflammation, skin carcinogenesis and systemic damage.

Ultraviolet (UV) radiation-induced chronic inflammation contributes to all stages of skin tumor development. In addition, gender plays an important role in inflammatory diseases or cancer. In this study, histopathology changes, hematology, oxidative stress and inflammatory response were used to evaluate sex differences in UV-induced chronic inflammation-associated cancer development. The results showed that the male and female mice had photoaging damage at the 9th week. However, skin tumors only appeared in male mice at 31st week. Furthermore, UV increased ROS production, p65, p-p65, IL-6 and TNF-α protein expressions in skin, and these factors elevated more in male mouse model. Hematology results showed that the parameters of blood systemic inflammation were changed in different degrees in model groups, while the pathological results showed inflammatory cell infiltration in the internal organs of both model groups in varying degrees. These results indicate that there are gender differences in UV-induced skin inflammation, carcinogenesis and systemic damage. Moreover, male mice are more sensitive to UV irradiation, which may be responsible to greater oxidative stress and inflammatory damage.