Single Whole-body Irradiation Research Articles

Effects of lactoferrin on X-ray-induced intestinal injury in Balb/C mice

Intestinal injury is common after radiotherapy. We aim to investigate the effects of lactoferrin (Lf) on X-ray-induced intestinal injury in Balb/C mice. In assessing animal survival, a total of 40 animals were assigned randomly to 8Gy group, 2mg Lf+8Gy group, 4mg Lf+8Gy group, and 6mg Lf+8Gy group. Mice were administered with Lf intraperitoneally and exposed to single whole-body X-ray irradiation. Lf administration lasted for 3 days. Survival rate was compared among groups. For the observation of intestinal injury, a total of 60 animals were divided randomly into control group, 5Gy group, 2mg Lf+5Gy group, and 4mg Lf+5Gy group. Lf was administered once a day. Five mice in each group were randomly sacrificed at days 1, 3, and 9 after irradiation. Fasting blood was used to determine serum levels of pro-inflammatory cytokines IL-6 and TNF-α, and anti-inflammatorycytokine IL-10. Intestinal tissues were collected to examine histological changes and determine the protein expression levels of NF-κB, IKKα and IKKβ. Mean survival time was 4.30±1.34, 4.20±0.71, 5.75±2.44 and 6.70±2.54 days in four groups, respectively, with significantly longer duration in 6mg Lf+8Gy group than in the 8Gy group. Survival rate was significantly higher in 4mg Lf+8Gy group and 6mg Lf+8Gy group, compared with the 8Gy group. For intestinal histology, the radiation-induced injury was considerably improved in the 2mg Lf+5Gy and 4mg Lf+5Gy groups. Villus length and its ratio to crypt depth significantly increased in the two Lf intervention groups. Compared with 5Gy group, serum levels of IL-6 and TNF-α significantly decreased in the two Lf intervention groups at days 3 and 9. Furthermore, Lf significantly reduced the radiation-induced expression of IKKα/β and NF-κB at day 3 and/or day 9. Lf extended the survival time of radiated mice and improved intestinal injury by decreasing inflammatory cytokines and downregulating NF-κB expression.

Radioprotection of mice by lactoferrin against irradiation with sublethal X-rays

The influence of a host defense protein, lactoferrin (LF), contained in exocrine secretions such as milk, on radiation disorder was investigated. A total of 25 C3H/He mice in each of two groups were maintained with 0.1% LF-added and LF-free diets, respectively, for one month. The mice were then treated with single whole-body X-ray irradiation at a sublethal dose (6.8 Gy), and the survival rate after irradiation was investigated. The survival rate at 30 d after irradiation was relatively higher in the LF group than in the control group (LF-free), (85 and 62%, respectively). The body weight 15 d after X-ray irradiation was also significantly greater in the LF group than in the control group. The hemoglobin level and hematocrit value were higher in the LF group at 5 d before X-ray irradiation. Another 52 mice underwent whole-body X-ray irradiation at the sublethal dose (6.8 Gy), and then LF was intraperitoneally injected once at 4 mg/animal to half of them. The survival rate in LF-treated mice 30 d after irradiation was 92%, significantly higher than in mice treated with saline (50%) (P = 0.0012). In addition, LF showed hydroxyl radical scavenger activity in vitro. These findings suggest that LF may inhibit radiation damage.

Insights into the Protective Mechanisms of Tamoxifen in Radiotherapy-Induced Ovarian Follicular Loss: Impact on Insulin-Like Growth Factor 1

Radiotherapy is one of the most common and effective cancer treatments. However, it has a profound impact on ovarian function, leading to premature ovarian failure. With the hope of preserving fertility in cancer survivors, the need for an effective radioprotective therapy is evident. The present study investigated the mechanism of the potential radioprotective effect of tamoxifen (TAM) on γ-irradiation-induced ovarian failure on experimental rats and the impact of the IGF-1 in the underlying protective mechanisms. Female Sprague Dawley rats were either exposed to single whole-body irradiation (3.2 Gy; lethal dose [LD₂₀]) and/or treated with TAM (1 mg/kg). γ-Irradiation caused an array of ovarian dysfunction that was evident by assessment of hormonal changes, follicular development, proliferation marker (proliferating cell nuclear antigen), and oxidative stress as well as apoptotic markers. In addition, IGF-1/IGF-1 receptor axis expression was assessed using real-time RT-PCR and immunolocalization techniques. Furthermore, fertility assessment was performed. TAM significantly enhanced follicular development and restored the anti-Mullerian hormone level. Moreover, it ameliorated the deleterious effects of irradiation on oxidative stress, proliferating cell nuclear antigen expression, and apoptosis. Interestingly, TAM was shown to enhance the ovarian IGF-1 but not IGF-1 receptor, a property that contributed significantly to its radioprotective mechanisms. Finally, TAM regained the fertility that was lost after irradiation. In conclusion, TAM showed a radioprotective effect and saved the ovarian reserve and fertility through increasing anti-Mullerian hormone and the local IGF-1 level and counteracting the oxidative stress-mediated apoptosis.

Alterations in the rat forebrain apoptosis following exposure to ionizing radiation

Ionizing radiation commonly used in the radiotherapy of brain tumours can cause adverse side effects to surrounding normal brain tissue. The most significant response of adult brain to radiation damage is induction of apoptosis. The adult mammalian subventricular zone (SVZ) of the brain lateral ventricles (LV) and their subsequent lateral ventricular extension, the rostral migratory stream (RMS), is one of the few areas, which retains the ability to generate new neurons and glial cells throughout life. Taking into account the fact, that ionizing radiation is one of the strongest exogenous factors affecting cell proliferation, the aim of the present study was to investigate the occurrence of radiation-induced apoptosis in this neurogenic region. Adult male Wistar rats were investigated 1, 5 or 10 days after single whole-body gamma irradiation with the dose of 3 Gy. Apoptotic cell death was determined by in situ labelling of DNA nick ends (TUNEL) and fluorescence microscopy evaluation of TUNEL-positive cells. Considerable increase of apoptotic TUNEL-positive cells was observed 24 hrs after irradiation in caudal parts of RMS; i.e. in the vertical arm and elbow of RMS. Initial increase was followed by strong reduction of apoptosis in the RMS and by secondary over-accumulation of apoptotic cells in the animals that survived ten days after exposure. Results showed, that the proliferating population of cells, arisen in SVZ are highly sensitive to radiation-induced apoptosis. This observation should have implications for clinical radiotherapy to avoid complications in therapeutic brain irradiation.

Punica Granatum Peel Extract Protects Against Ionizing Radiation-Induced Enteritis And Leukocyte Apoptosis In Rats

Radiation-induced enteritis is a well-recognized sequel of therapeutic irradiation. Therefore we examined the radioprotective properties of Punica granatum peel extract (PPE) on the oxidative damage in the ileum. Rats were exposed to a single whole-body X-ray irradiation of 800 cGy. Irradiated rats were pretreated orally with saline or PPE (50 mg/kg/day) for 10 days before irradiation and the following 10 days, while control rats received saline or PPE but no irradiation. Then plasma and ileum samples were obtained. Irradiation caused a decrease in glutathione and total antioxidant capacity, which was accompanied by increases in malondialdehyde levels, myeloperoxidase activity, collagen content of the tissue with a concomitant increase 8-hydroxy-2'-deoxyguanosine (an index of oxidative DNA damage). Similarly, pro-inflammatory cytokines (TNF-alpha, IL-1beta and IL-6) and lactate dehydrogenase were elevated in irradiated groups as compared to control. PPE treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. Furthermore, flow cytometric measurements revealed that leukocyte apoptosis and cell death were increased in irradiated animals, while PPE reversed these effects. PPE supplementation reduced oxidative damage in the ileal tissues, probably by a mechanism that is associated with the decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms. Adjuvant therapy of PPE may have a potential to support a successful radiotherapy by protecting against radiation-induced enteritis.

Elaeocarpus sylvestris modulates gamma‐ray‐induced immunosuppression in mice: implications in radioprotection

The study investigated the potential of Elaeocarpus sylvestris var. ellipticus (E.S.), which contains 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG), to protect mice from radiation injury by single whole-body irradiation (WBI) in vivo. The results from the present study demonstrate that the E.S. extract significantly improved the rate and duration of survival beyond that of untreated, irradiated control mice. The counts of endogenous colony forming units (CFU) increased in E.S.-treated mice, indicating that E.S. induced the regeneration of hematopoietic cells. E.S. treatment also accelerated the proliferation and recovery of lymphocytes and granulocytes, compared with those levels in untreated, irradiated controls. These results suggest that E.S. extract increases the survival time of mammals exposed to ionizing radiation by intensifying the victims' hematopoietic repair capacities. Therefore, it is concluded that the E.S. extract may be an effective agent of protection from radiation-induced injuries.

Exacerbation of autoimmune thyroiditis by a single low dose of whole-body irradiation in non-obese diabetic-H2h4 mice

Purpose: To evaluate how irradiation affects thyroid autoimmunity in mouse models of Hashimoto's thyroiditis and Graves' hyperthyroidism.Materials and methods: Non-obese diabetic (NOD)-H2h4 mice spontaneously develop anti-thyroglobulin (Tg) antibodies and thyroiditis when supplied with sodium iodine (NaI) in the drinking water. BALB/c mice develop anti-thyrotropin receptor (TSHR) antibodies and hyperthyroidism following immunization with adenovirus expressing TSHR (Ad-TSHR). Mice were irradiated as follows: A single whole-body irradiation with 0.05, 0.5 or 3 Gy one week before or after the beginning of NaI or immunization with Ad-TSHR, fractionated whole-body irradiations with 0.05 Gy twice a week or 0.5 Gy once a week from one week before NaI or Ad-TSHR immunization, or a single regional irradiation to the thyroid gland with 0.5 Gy one week before NaI. The effect of a single irradiation with 0.05, 0.5 or 3 Gy on splenocytes was also evaluated.Results: A single whole-body irradiation with 0.5 Gy one week before NaI exacerbated thyroiditis and increased anti-Tg antibody titers in NOD-H2h4 mice. In contrast, any irradiation protocols employed did not affect incidence of hyperthyroidism or anti-TSHR antibody titers in BALB/c mice. High-dose irradiation increased the relative ratios of effector T cells to regulatory T cells (an indication of enhanced immune status) but kills most of T cells.Conclusions: These results indicate that a single whole-body low-dose irradiation with 0.5 Gy exacerbates thyroiditis in NOD-H2h4 mice, data consistent with some clinical evidence for increased incidence of thyroid autoimmunity by environmental irradiation.

English

Previously the higher phospho-ELK-1 (p-ELK-1) expression in enterocytes 24-96 h aftersub-lethal irradiation was measured. Therefore, purpose of this study is to examine in vivoexpression of this common ERK1/2 and JNK/SAPK target during the first hours after low-doseirradiation to assess ability of this transcriptional factor as a biodosimetric marker after the singlewhole-body irradiation. The laboratory rats were randomly divided into 12 groups and irradiatedwith whole-body gamma radiation dose of 0.25 Gy, 0.5 Gy, and 1.0 Gy. Samples of jejunum weretaken 1 h, 2 h, 4 h, and 24 h later, the p-ELK-1 was immunohistochemically detected and thenits expression was measured by computer image analysis. A significantly increased expressionof p-ELK-1 in enterocytes was measured 1 h, 2 h, and 4 h after 0.5 Gy and 1.0 Gy irradiation,24 h after all radiation doses, respectively. Peak of p-ELK-1 expression was observed at 0.5 Gyat all time points after irradiation. The detection of p-ELK-1 might be considered as a perspectivequalitative in vivo biodosimetric marker for military purposes expressed by proliferative cells24 h after irradiation with doses from 0.25 Gy to 1.0 Gy.

Activation of Immune Functions by Low-dose, Whole-body Irradiation with .GAMMA.-Rays

We first examined whether the increase of glutathione level induced by low-dose γ-ray irradiation is involved in the appearance of enhanced natural killer (NK) activity and antibody-dependent cellular cytotoxicity (ADCC), leading to delayed tumor growth in Ehrlich solid tumor (EST) -bearing mice. NK activity in ICR mouse splenocytes was significantly increased from 4h to 6h after a single whole-body γ-ray irradiation at 0.5 Gy, and thereafter decreased almost to the zero-time level by 24h post-irradiation. ADCC was also increased significantly in a similar way. Reduced glutathione exogenously added to splenocytes obtained from normal mice enhanced both NK activity and ADCC in a dose-dependent manner. The inhibitory effect of the radiation on tumor growth was then examined in EST-bearing mice. Repeated low-dose irradiation (0.5 Gy, four times, before and within an early time after the inoculation) significantly delayed the tumor growth.Finally, the effect of single low-dose (0.5 Gy), whole-body γ-ray irradiation on immune balance was examined in order to elucidate the mechanism underlying the anti-tumor immunity. The percentage of B cells in blood lymphocytes was selectively decreased after the radiation, concomitantly with an increase in that of helper T cell population. The IFN-γ level in splenocyte culture prepared from EST-bearing mice was significantly increased 48h after the radiation, though the level of IL-4 was unchanged. IL-12 secretion from macrophages was also enhanced by the radiation. These results suggest that low-dose γ-rays induce Th1 polarization and enhance the activities of tumoricidal effector cells, leading to a delay of tumor growth.

Intestinal Tumorigenesis in Min Mice is Enhanced by X-irradiation in an Age-dependent Manner

We examined the effect of X-irradiation on intestinal tumorigenesis in Min (multiple intestinal neoplasia) mice. Single whole-body irradiation was given to mice of various ages from newborn to young adults. On the C57BL/6J (B6) background, X-irradiation increased tumor multiplicity of the small intestine exposed at ages from 2-3 days to 24-25 days, with a peak of 2.7-fold increase at 10-12 days of age; exposure at later ages resulted in only a slight increase. X-irradiation also increased colonic tumors; however, the susceptible age period appeared earlier than that of the small intestine; the peak value of 4.6-fold increase was observed in the exposure at around 2-3 days of age. Irradiation at 24 days or later ages showed almost no effect on the colonic tumor induction. On the (B6 x MSM)F1 background, X-irradiation resulted in 2.7-fold increase in the small intestinal tumors, but no increase in the colonic tumors, and besides, the age dependency observed in the small intestinal tumors was much attenuated. Collectively, we conclude that tumorigenic efficacy of X-irradiation in Min mice was determined by the combination of the target organ, the age at exposure, and the genetic background.

Age-specific ultrastructural postradiation changes in intestinal endocrine cells.

Age-specific ultrastructural postradiation changes in the main types of duodenal endocrine cells (apudocytes) were studied in rats 6 and 12 months after single whole-body irradiation in doses of 7 and 7.5 Gy. Ultrastructural disorganization of different severity was detected, which depended on apudocyte type and term postradiation. Degranulation was the basic mechanism of hormone secretion in delayed periods after the exposure.

Protective effects of 5,6,7,8-tetrahydroneopterin against X-ray radiation injury in mice

The protective effects of 5,6,7,8-tetrahydroneopterin (NH4) against radiation injury in mice were studied. (C57BL/6×A/J)F1 (B6A) mice received a single whole-body irradiation dose of 200, 400, 700 or 800 cGy of X-rays. NH4 (30 mg/kg body weight) or phosphate-buffered saline (PBS) was injected intraperitoneally into irradiated mice 10 min before and after the irradiation and again after 6 h. All mice which received the 800 cGy radiation+PBS died between 8 and 11 days after the treatment. In contrast, those which also received NH4 demonstrated a significantly prolonged survival time and 40% lived more than 5 months. Total numbers of thymocytes and spleen cells on day 5 post-irradiation were dramatically reduced in line with the radiation dose. The survival was significantly enhanced by NH4 in treated mice. The proliferation of spleen cells in mice stimulated by concanavalin A (Con A) or lipopolysaccharide (LPS) was also greater in NH4 treated mice. The immune response of survivors 5 months after 800 cGy+NH4 treatments, against Con A, LPS, allogenic mouse, and sheep red blood cells had essentially recovered to the levels of normal mice. These results indicate that NH4 had an important role in modifying radiation injury.

Biological Defense and Adaptation Induced by Low Dose Radiation

The present paper reviews recent experimental data obtained from studies on stimulation of immune functions and induction of cytogenetic adaptive response by low level radiation. An attempt is made to integrate recent observations in the author's laboratory. Emphasis is given to the effects of single and chronic whole-body irradiation (WBI) with X- or γ-rays. A schematic diagram of the interactions of the immune cells after low dose radiation is proposed to elucidate the possible cellular mechanism of the stimulatory effect of low dose radiation on immunity. Experimental data on the dose-effect relationship of induction of cytogenetic adaptive response in somatic and germ cells by single and chronic whole-body irradiation are presented. In the analysis of the molecular mechanism of the stimulatory effect of low dose radiation the activation of signal transduction pathways and induction of genes related to cell survival and proliferation are emphasized. The implications of the existing data are discussed and future investigations for the elucidation of possible common molecular basis of stimulation of biological defense and adaptation by WBI with low doses are suggested.

Lymphocyte disappearance and reappearance after a single whole-body irradiation dose of 5 Gy

The effects of a single exposure to 5 Grays of caesium gamma rays administered at a high-dose rate were investigated in rat lymphocyte populations. Such a dose completely depleted the B-cell population but never totally depleted the T-cell population. T and B lymphocytes reappeared in the spleen after 10-15 days and somewhat later in the mesenteric lymph nodes and Peyer's patches. In the spleen, non-circulating B lymphocytes of the marginal zone reappeared after a few days, as did the B lymphocytes of the follicles. Lymphoid tissues were observed to have recovered their normal aspect between days 50 and 60 after irradiation; however, even at that time, the germinal centres had not yet returned to normal.

Dynamics of nitrite-induced methemoglobin formation after total gamma-ray irradiation of rats

One trend in the design of atomic power stations (APS) based on fast neutrons is the development of APS in which dissociating nitrogen tetroxide is used as heat carrier and as working heat. Here, the authors study the combined action of ionizing radiation and of sodium nitrite on methemoglobin formation associated with the action of nitrites as a metabolic product of nitrogen oxide metabolism. Experiments were carried out on male Wistar rats weighing 180-200 g. Single whole-body irradiation was given on the UGU-420 gamma-ray source in doses of 77.4 and 180.6 mCi/kg body weight. The dynamics of changes in the methemoglobin concentration was monitored on a VSU-2-P spectrophotometer at 540-630 nm. A diagram showing the relationship between nitrite-induced methemoglobin formation and dose and time elapsing after irradiation is shown.

Radiation-induced changes in gentamicin pharmacokinetics.

Decreased clearance of i.v. or intratracheally administered gentamicin was observed in rats following single whole-body irradiation. 6 Gy 60Co. reaching its lowest rate on the 7th post-irradiation day. Simultaneously the absorption rate of gentamicin from the lungs was found to be increased.

The Long-Term Effect of Single Whole-Body Irradiation on Graft-versus-Host Reactivity in Mice in Comparison with the Effect of Bone Marrow Reconstitution and of Continuous Irradiation

In order to look into the causes of the long-term radiation effect on graft-vs-host (GVH) reactivity in mice, the effect of continuous irradiation over a year (total dose of 1800 R) and of bone marrow reconstitution after 600 R acute irradiation were compared with those of 600 R acute irradiation alone in 15-month-old C57BL mice. The reconstitution by syngeneic bone marrow shortly after irradiation did not prevent the persistent impairment of the GVH reactivity. Despite the reduction in spleen size in irradiated mice, the continuous irradiation affected the GVH reactivity on a per cell basis to a lesser extent than did the 600 R acute irradiation. A similar decrease was found in splenic colony forming units (CFU). These results suggest that the long-term effect of the 600 R acute irradiation on the GVH reactivity is not due to the direct and persistent damage to the cells; therefore we suspect that it is due to the alterations in the factors required for the successful maturation and proliferation of lymp...

Late Somatic Effects in Female RF/Un Mice Irradiated with Single Doses of 14-MeV Fast Neutrons

SummaryRF/Un female mice (∼ 1700 animals), 10–11 weeks old, were given a single whole-body irradiation with 14 meV neutrons (either 0, 50, 100, 200 or 400 rads) at a dose-rate of 1–2 rads/min. The mean age at death for 30-day survivors decreased with increasing dose. The incidence of thymic lymphoma and of myeloid leukaemia increased with dose. The incidence of ovarian tumours increased with dose to a maximum at 100 rads. Radiation enhanced the decline in haematocrit with age. Lens opacities developed in all irradiated groups by 3 months after exposure, progressed at a dose-dependent rate, and ultimately attained a level of severity which greatly exceeded any senile changes in the controls. Other common non-neoplastic diseases were not increased in incidence by irradiation, but all occurred earlier in irradiated animals. The results suggest that 14 meV neutrons are more effective than gamma-rays for shortening life and for producing lens opacities but not necessarily for inducing neoplasms, depending on t...

X線及び20-Methylcholanthreneにより惹起せしめたRF系マウス白血病の無細胞濾液移植に関する研究

ABS>The incidence of leukemia in RF mice exposed to a single whole-body irradiation of 350 r x-rays was 77.4%, in 41 out of 53 animals. In all, 20 developed the thymic and 20 the non-thymic lymphocytic leukemia, while only one developed myelogenous leukemia. The incidence of leukemia by 20- methylcholanthrene painting was 88% in 22 out of 25 animals. Of them, 12 developed lymphocytic leukemia and 10 myelogenous leukemia. Cell-free filtrates from the leukemic mice, which were induced by a single whole-body x irradiation, were inoculated to the newborn mice of the same strain less than 16 hours old. Two (18.7%) of the twelve inoculated animals developed leukemia on the 357th and 374th days, respectively, after the inoculation. Attempts to inoculate cell-free filtrate from 20-methylcholanthrene-induced leukemic RF mice to newborn mice of the same strain were successful. Cell-free filtrate from the myelogenous leukemic mouse caused lymphocytic leukemia in one of three inoculated mice. This is suggestive of the possibility of transformation of the type of leukemia during cell-free transmission. Virus-like particles were demonstrated by electron microscope in the lymph nodes of 20-methylcholanthrene-induced leukemic mice. The results suggest that x-ray and chemical carcinogens may act to induce leukemia or mammary carcinomamore » by the activation of a latent virus naturally resident in the RF mouse. (P.C.H.)« less

Circulating platelets in mice subjected to simultaneous x-ray and ultra-violet irradiation.

THE circulating platelet count of mice increases significantly after ultra-violet irradiation. Five to seven days after a single whole-body ultra-violet irradiation the increase is about 100 per cent. Para-biosis experiments, as well as the positive effect of isologous serum transfer, suggested that humoral factor(s) are responsible for the thrombocytopoietic effect and the agent seemed to be a protein-like macromolecule1 as already described for human serum2. In the present experiments we investigated the simultaneous action of whole-body X-ray irradiation, that is, a procedure causing severe thrombocytopenia, and ultra-violet radiation, that is, a procedure causing marked thrombocytosis.