Free thymidine in the blood serum of irradiated rats with different levels of cellular depletion of the thymus and spleen

The levels of the postirradiation thymidinemia, with an equal degree of the proceeding cell depletion of lymphoid organ tissues caused by the administration of dexamethasone and exposure of rats to 3 Gy radiation, markedly varied. Three days after the injection of the hormone, the organism responded to irradiation by an increase in the concentration of thymidine in blood serum in the same manner as intact animals did. The preirradiation with a dose of 3 Gy reduced sharply the ability of the organism to respond the repeated irradiation (after 3 days) by thymidinemia. There was a lesser increase in the thymidine concentration in the blood after the injection of dexamethasone than after irradiation inducing the same cell depletion of the thymus and spleen.     

载氢-纳米氧化铈微泡对小鼠造血系统抗辐射作用的分析

为探讨载氢-纳米氧化铈微泡对小鼠辐射损伤的防护作用。本研究检测载氢-纳米氧化铈微泡的表征,并将60只BALB/c小鼠随机分为正常对照组、照射对照组、载氢-纳米氧化铈微泡组。小鼠经6Gy x射线一次性全身照射(剂量率2 Gy/min)。于照射后3 d和8 d处死小鼠,检测其外周血细胞数、脾脏和胸腺指数、骨髓和脾脏组织病理学变化。结果显示,照射后3 d和8 d,与正常对照组相比,载氢-纳米氧化铈微泡组和照射对照组的白细胞均明显下降,相比照射对照组,载氢-纳米氧化铈微泡组有改善(p<0.05或p<0.01);而载氢-纳米氧化铈微泡组和照射对照组的红细胞数和血红蛋白均略有下降,但差异无统计学意义。与正常对照组相比,微泡组的胸腺指数、脾脏指数均有下降,和照射对照组相比,载氢-纳米氧化铈微泡组的胸腺指数明显改善(p<0.05或p<0.01)。照射后3 d,与正常对照组相比,照射对照组的骨髓细胞较少,存在细胞碎片,载氢-纳米氧化铈微泡组骨髓细胞数量略有减少,存在细胞核松散现象。而照射后8 d,与正常对照组相比,照射对照组的骨髓细胞几乎找不到,载氢-纳米氧化铈微泡组骨髓细胞有一定数量,存在细胞凋亡现象。本研究表明,载氢-纳米氧化铈微泡通过保护造血组织、改善造血功能,对机体起到一定的辐射防护作用。     

Modification of p53 protein profile by gamma irradiation followed by methyl donor starvation

The possible beneficial radio-protective effects of one-carbon transfer agents namely folate, choline and methionine have been the subject of extensive investigation. Ionizing radiation is known to extensively damage the DNA. One-carbon transfer agents have been proposed to have important role in context of DNA repair via their role in purine and thymidylate synthesis and in DNA methylation. Sufficient dietary availability of one-carbon transfer agents therefore, might have ability to modify radiation effects. In present study modifications in level of tumor suppressor protein p53 by gamma irradiation followed by methyl donor starvation was observed. Experiments showed an increase in nuclear and cytoplasmic p53 protein concentration in liver, spleen and thymus. The overall rise in the level of p53 protein in liver was found to be less than that in spleen and thymus. Moreover significant heterogeneity in the basal level of expression of the p53 protein in liver, spleen and thymus was observed as the level of p53 protein in spleen and thymus was found to be 7–8 fold more than that in liver. Results indicated that radiation stress followed by methyl donor starvation could significantly induce p53 protein in spleen and thymus where there was a dramatic accumulation of p53 following irradiation, while in other tissues, particularly the liver, no such dramatic response was seen. Folate contribution of intestinal bacteria was found to influence p53 protein levels. Our observations indicated a prominent role played by the methyl donors in protecting the cell against harmful effects of ionizing radiation.     

T cell differentiation in lethally irradiated and reconstituted mice: stem cell influx demonstrated with immunoperoxidase technique.

Using both an anti-stem cell serum and an anti-T cell serum the influx of stem cells in mouse thymus and spleen after lethal irradiation and reconstitution was determined by immunoperoxidase staining. In both organs a rapid influx was observed reaching a maximum on Day 5 after irradiation and cell transfer. Thereafter a decline of stem cells took place while the number of T cells in the thymus increased gradually, reaching a maximum on Day 12. T cells could only be detected in the spleen after 3 weeks.     

Circulating Interleukin-18 as a Biomarker of Total-Body Radiation Exposure in Mice,Minipigs, and Nonhuman Primates (NHP)

We aim to develop a rapid, easy-to-use, inexpensive and accurate radiation dose-assessment assay that tests easily obtained samples (e.g., blood) to triage and track radiological casualties, and to evaluate the radioprotective and therapeutic effects of radiation countermeasures. In the present study, we evaluated the interleukin (IL)-1 family of cytokines, IL-1β, IL-18 and IL-33, as well as their secondary cytokines’ expression and secretion in CD2F1 mouse bone marrow (BM), spleen, thymus and serum in response to γ-radiation from sublethal to lethal doses (5, 7, 8, 9, 10, or 12 Gy) at different time points using the enzyme-linked immune sorbent assay (ELISA), immunoblotting, and cytokine antibody array. Our data identified increases of IL-1β, IL-18, and/or IL-33 in mouse thymus, spleen and BM cells after total-body irradiation (TBI). However, levels of these cytokines varied in different tissues. Interestingly, IL-18 but not IL-1β or IL-33 increased significantly (2.5–24 fold) and stably in mouse serum from day 1 after TBI up to 13 days in a radiation dose-dependent manner. We further confirmed our finding in total-body γ-irradiated nonhuman primates (NHPs) and minipigs, and demonstrated that radiation significantly enhanced IL-18 in serum from NHPs 2–4 days post-irradiation and in minipig plasma 1–3 days post-irradiation. Finally, we compared circulating IL-18 with the well known hematological radiation biomarkers lymphocyte and neutrophil counts in blood of mouse, minipigs and NHPs and demonstrated close correlations between these biomarkers in response to radiation. Our results suggest that the elevated levels of circulating IL-18 after radiation proportionally reflect radiation dose and severity of radiation injury and may be used both as a potential biomarker for triage and also to track casualties after radiological accidents as well as for therapeutic radiation exposure.     

染料木黄酮改善γ射线损伤小鼠抗氧化功能的作用

用137Csγ射线照射雄性昆明小鼠,观察饲料中补充染料木黄酮(Genistein,Gen)对抗氧化功能的保护作用,探讨其抗辐射作用的机制。结果表明,Gen可以提高辐射小鼠脾和胸腺组织总抗氧化能力(T-AOC)、降低血清、肝脏和胸腺组织丙二醛(MDA)水平;显著提高辐射小鼠抗氧化功能。     

转基因MSC对放射损伤胸腺组织修复的研究

目的：探讨转基因MSC能否修复放射损伤的胸腺。方法：雌性BALB/C小鼠120只,随机分为4组：对照组30只,予以假照射;照射组30只,60Coγ射线胸腺单次照射,剂量为9Gy;照射＋MSC组30只,9Gy照射后2小时输注转基因MSC;对照＋MSC组30只,假照射后2小时输注转基因MSC。照射后1、7、14、21、28天检测各组小鼠血像、胸腺指数及胸腺病理。结果：照射＋MSC组血像和胸腺指数在各个时间点均优于照射组,胸腺病理显示组织结构恢复明显加快。结论：转基因MSC能归巢至放射损伤胸腺并能促进胸腺的修复,为干细胞的临床应用提供了实验依据。     

Cytokine profiles in mice tissues after irradiation of the thymus projection area with femtosecond laser

The effects of pulsed femtosecond laser irradiation in the near ultraviolet region on the levels of cytokines in the thymus, blood, and skin of irradiated mice have been studied. Irradiation of the thymus projection area with low-intensity laser radiation in the near UV region of the spectrum showed significant changes in cytokine levels in the skin and thymus and, to a lesser extent, in the blood of irradiated mice. Laser irradiation with a power density of 20 mW/cm² affects the cytokine profile in the thymus: IFN-γ, IL-3, IL-4, IL-5, eotaxin, GM-CSF, and chemokine KC–factors that can affect differentiation and proliferation of the cells of the immune system in the gland. Conclusions: It is assumed that changes in the expression of cytokines in the thymus after laser irradiation are explained by the rearrangement of biochemical processes possibly associated with the maturation of cells in the gland.     

X-irradiation effects on thymidine kinase (TK): I. TK1 and 2 in normal and malignant cells

Abstract. The effect of radiation on TK is more complicated than would be expected from earlier results on bone marrow cells ( Feinendegen et al. 1984 , Int. J. Radiat. Biol. 45, 205). TK activity increased at 0.01 Gy and then decreased up to 1 Gy in mouse spleen. In contrast to the results for the spleen, an increase in activity at 0.1 Gy was seen in mouse thymus. The activity of dephosphorylated TK1 (TK1a) in both spleen and thymus was reduced to 50% after irradiation at 0.5–1 Gy. The degree of phosphorylation (TK1b/TK1a ratio) changed in spleen, but not in thymus. The activity of TK2 in mouse liver increased at 3 h after 5 Gy by about 60%. In mouse ascites tumour, a dose-independent (1–5 Gy) oscillating TK1 activity was found up to 24 h, especially for TK1a and TK1b. The amount of TK1 was unchanged up to 12 h, but decreased at 24 h. This suggests that the differences in the changes in the degree of phosphorylation of TK1 after irradiation among spleen, thymus and ascites tumour further underline the complexity of the response of TK1 activity to irradiation. The dramatic change in the activities of TK1a and TK1b may illustrate that both of them are more radiosensitive than TK-h, a variant with mixed TK1 and TK2 properties.     

Short- and long-term effects of whole-body irradiation with fission neutrons or X rays on the thymus in CBA mice

Young adult (6 weeks old) female CBA mice were exposed to whole-body irradiation with either 2.5-Gy fast fission neutrons of 1 MeV mean energy or 6.0-Gy 300 kVp X rays at centerline dose rates of 0.1 and 0.3 Gy/min, respectively. The weight of spleen and animal and the weight, cellularity, and histological structure of the thymus were studied at different times after irradiation. Thymic recovery after whole-body irradiation showed a biphasic pattern with minima at 5 and 21 days after irradiation and peaks of regeneration at Days 14 and 42 after X irradiation or at Days 14 and 70 after neutron irradiation. After the second phase of recovery, a marked decrease in relative thymus weight and cellularity was observed, which lasted up to at least 250 days after irradiation. Splenic recovery showed a monophasic pattern with an overshoot on Day 21 after irradiation. After neutron irradiation a late decrease in relative spleen and animal weight was observed. The observed late effects on thymus and spleen weight and thymus cellularity are discussed in terms of a persistent defect in the bone marrow.     

The cytokinesis-block micronucleus assay as a biological dosimeter in spleen and peripheral blood lymphocytes of the mouse following acute whole-body irradiation

To evaluate the application of the cytokinesis-block (CB) micronucleus (MN) assay as a biological dosimeter following in vivo exposure to ionising radiation we determined the micronucleus frequency in spleen and peripheral blood lymphocytes of the mouse, serially, for 14 days following acute whole-body irradiation. The baseline MN frequency of spleen lymphocytes (7.86 +/- 0.68, mean +/- 1 SD) was significantly (p less than 0.001) elevated when compared to that for peripheral blood lymphocytes (4.10 +/- 0.53). Immediately after irradiation there was a substantial dose-related increase in MN, but the MN frequencies in spleen lymphocytes (120.2 +/- 9.4 for 1 Gy; 409.5 +/- 38.4 for 2 Gy) were significantly (p less than 0.009) elevated compared to those in peripheral blood lymphocytes (78.0 +/- 7.0 for 1 Gy; 200.2 +/- 10.9 for 2 Gy). During the 14 days after irradiation, the MN frequency in spleen lymphocytes declined gradually to approximately half of the value observed immediately after irradiation. By contrast the MN frequency in peripheral blood lymphocytes increased during the week after irradiation, but ultimately MN frequencies in blood and spleen became approximately the same by day 14. Study of isolated murine lymphocytes irradiated in vitro showed that the number of MN generated by a given dose of radiation was approximately 2-3 times greater than the number generated by in vivo irradiation. These results suggest that measurement of MN in vivo after irradiation can be used as an in vivo dosimeter. However, precise dosimetry is probably affected by factors such as kinetic changes in different lymphocyte populations and possibly by in vivo factors which influence sensitivity of cells to radiation.     

The effect of low exposure-rate gamma irradiation on T and B lymphocyte function in the mouse

The effect of chronic irradiation on T and B cell numbers and function was studied in mice. Cobalt 60 gamma radiation at 6 R/hour reduced the numbers of anti-SRBC PFC in the spleen, with minimal levels recorded after total exposures of 1000-2000 R. Recovery was incomplete after 1000 R, reaching only 40-50 per cent of normal in four months and remaining at that level for the animal's lifetime. The long-term deficiency in PFC formation was not due to a quantitative lack of T or B cells since normal cell numbers were observed in the spleen 60-144 days after 1000 R. Adoptive transfer studies with combinations of bone marrow and thymus cells, or of splenic T and B cells, from normal and irradiated mice, revealed functional defects in both cell compartments during the first two months. Normal and near normal function of T and B cells occurred 100 days postirradiation, a time when the splenic in vivo response was still only 50 per cent of the controls. The latter observation suggests that the microenvironment of the chronically irradiated spleen alters factors regulating T and B cell interactions in response to a T-dependent antigen.     

Effect of sublethal ionizing radiation on rat Peyer's patch lymphocytes

After sublethal doses of ionizing radiation, rat Peyer's patch lymphocytes regenerated significantly more slowly than lymphocytes from spleen, thymus, and peripheral lymph nodes. Long Evans rats were exposed to 150 rad (40 rad/min) of whole-body irradiation from a 60Co, gamma-emitting source. On Days 1-20 postirradiation, single cell suspensions of lymphocytes from thymus, spleen, peripheral lymph nodes, and Peyer's patches were stained with mouse monoclonal antibody reagents specific for rat lymphocyte subpopulations (Ia+ cells, non-helper T-cell subsets, and helper T-cell subsets). Cells were then counterstained with Texas Red-conjugated, goat anti-mouse IgG and, at the same time, were also stained with fluorescein diacetate to determine viable lymphocytes. The stained lymphocytes were analyzed using a dual-laser, fluorescent-activated cell sorter (Becton-Dickinson FACS-II) from which the percentage of each lymphocyte subpopulation was determined. From our studies, we found that all subpopulations of lymphocytes were affected similarly by irradiation. In addition, we observed that viable lymphocyte subpopulation in thymus, spleen, and peripheral lymph nodes from irradiated animals returned to normal (nonirradiated control animals) levels 5-12 days postirradiation, while viable lymphocyte subpopulations in Peyer's patches from irradiated animals remained suppressed up to 20 days postirradiation. These results suggest that either the lymphocytes or, more likely, the microenvironment of Peyer's patches is more greatly damaged by ionizing radiation than that observed in other lymphoid tissue.     

Radiation effects on regeneration and T-cell-inducing function of the thymus

Radiation effects on regeneration and T-cell-inducing function of the thymus were studied in three sets of experiments. When TXB mice were grafted with 1-week-old thymus which had been previously irradiated at various doses, an exponential decrease was observed in the morphological regeneration of the thymus grafts and in their T-cell-inducing function at doses of 600 R and over, showing about 10% that of the control at 1500 R. When in situ thymus of adult mice was locally irradiated, the radiation effect on T-cell-inducing function was less pronounced as compared with the first experiment; i.e., about 40% of the control at 1797 R. When in situ thymus of 1-day-old newborn mice was locally irradiated, regeneration potential of 1-day-old newborn thymus was highly resistant to radiation exposure and no effect on immunologjcal functions was observed even by local irradiation of 2000 R.     

Low-dose total-body γ irradiation modulates immune response to acute proton radiation

Health risks due to exposure to low-dose/low-dose-rate radiation alone or when combined with acute irradiation are not yet clearly defined. This study quantified the effects of protracted exposure to low-dose/low-dose-rate γ rays with and without acute exposure to protons on the response of immune and other cell populations. C57BL/6 mice were irradiated with ??Co (0.05 Gy at 0.025 cGy/h); subsets were subsequently exposed to high-dose/high-dose-rate proton radiation (250 MeV; 2 or 3 Gy at 0.5 Gy/min). Analyses were performed at 4 and 17 days postexposure. Spleen and thymus masses relative to body mass were decreased on day 4 after proton irradiation with or without pre-exposure to γ rays; by day 17, however, the decrease was attenuated by the priming dose. Proton dose-dependent decreases, either with or without pre-exposure to γ rays, occurred in white blood cell, lymphocyte and granulocyte counts in blood but not in spleen. A similar pattern was found for lymphocyte subpopulations, including CD3+ T, CD19+ B, CD4+ T, CD8+ T and NK1.1+ natural killer (NK) cells. Spontaneous DNA synthesis by leukocytes after proton irradiation was high in blood on day 4 and high in spleen on day 17; priming with γ radiation attenuated the effect of 3 Gy in both body compartments. Some differences were also noted among groups in erythrocyte and thrombocyte characteristics. Analysis of splenocytes activated with anti-CD3/anti-CD28 antibodies showed changes in T-helper 1 (Th1) and Th2 cytokines. Overall, the data demonstrate that pre-exposure of an intact mammal to low-dose/low-dose-rate γ rays can attenuate the response to acute exposure to proton radiation with respect to at least some cell populations.     

Effects of single gamma-irradiation on the activity of ornithine decarboxylase in the thymus and pulmonary tissue]

In studying the dose (0.1-6 Gy) and time (2 h to 180 days) dependence of ornithine decarboxylase activity, it was found that deviations from the control were more pronounced in the thymus than in the pulmonary tissue. The radiation effect was a function of dose and time after irradiation. A nonmonotonous type of the dose-response curve was observed 7 days after irradiation: the radiation effect with a low dose (0.1 Gy) was opposite to that with sublethal doses (1-6 Gy).     

Recovery of hematopoiesis in mice following a continuous irradiation with a dose rate of 0.957 Gy/d and a total accumulated dose of 19.14 Gy. I. Bone marrow, spleen and thymus gland

This paper deals with the evaluation of histological changes in the bone marrow, spleen and thymus of mice after continuous irradiation with a dose rate of 0.957 Gy/day and a total accumulated dose of 19.14 Gy. Erythropoiesis in the spleen could be recovered quickly, significantly exceeding the spleen erythropoiesis of the controls on the seventh post-irradiation day. Myelopoiesis in the bone marrow could be recovered until the 21st day and erythropoiesis until the 28th day after the end of irradiation. Lymphopoiesis in the thymus could be recovered on the 28th day approximately and in the spleen roughly on the 60th day after the end of irradiation.     

The dynamic accumulation of a low-molecular physiologically active depressor factor and its biological effects in hemorrhagic shock]

A low-molecular factor (800-1000 D) was isolated from the blood serum of dogs using selective ultrafiltration. That factor was taken in various terms of the hemorrhagic shock development. Biological activity of the factor was determined in experiments on isolated hearts of dogs and lymphoid cells. It is found that the above factor decreases the contractile function of the isolated heart, disturbs energy formation, inhibits the antibody-forming function of the spleen as well as possesses a cytolytic effect on lymphocytes of the peripheral blood lympho-nodes and thymus.     

Changes in the concentration of serum fibronectin in irradiated animals

A study of the level of fibronectin in blood serum of Wistar rats at different times after gamma-irradiation (7.5 Gy) has demonstrated a considerable increase in its concentration after 3 days. This increase is a function of radiation dose absorbed (within the range from 1 to 10 Gy). The most pronounced changes are observed with serious and extremely serious forms of acute radiation sickness. The administration of cycloheximide 48 h after irradiation removes completely the increase in the level of blood serum fibronectin.     

口服卡介菌诱导免疫耐受的CD4+CD25+调节性T 细胞机制研究

目的:研究口服卡介菌诱导免疫耐受对CD4+CD25+调节性T细胞的影响。方法:采用口服MPB制备EAE大鼠模型,随机分为BCG组(0.5mg/kg)和EAE模型组(PBS),每组各15只,连续经口灌服给药14d,同时选取15只健康大鼠作为对照组。分别于免疫后15d、27d流式细胞术检测外周血、胸腺及脾脏中CD4+CD25+T淋巴细胞百分率,ELISA检测血清IL-6、TGF-β、IgE、IgG含量。结果:与EAE模型组相比,免疫后BCG组大鼠外周血、胸腺及脾脏中CD4+CD25+T淋巴细胞百分率增加,血清IL-6、TGF-β含量上升,血清IgE、IgG抗体水平下降。结论:口服BCG通过上调淋巴器官中CD4+CD25+T淋巴细胞比例,抑制效应性T细胞活性,发挥免疫耐受作用。