Serum proteins in rats after combined neutron and gamma irradiation

Quantitative changes of some selected serum proteins in rats irradiated with a single dose of 2 Gy neutrons were compared with protein changes in rats irradiated with an equal single neutron dose and subsequent continuous gamma irradiation using daily dose rate of 0.574 Gy up to the total dose of 6 Gy. On the basis of the values obtained from the diagrams of two-dimensional immunoelectrophoresis it was found that both irradiations entailed approximately equal quantitative changes of the serum concentrations of the proteins followed. The differences found concerned time intervals of the adjustment of the changes produced. After neutron irradiation reparation of the serum albumin occurred on 14th day, of A1-globulin concentrations on 28th day and of haptoglobin on 90th day, yet after combined neutron and gamma irradiation reparation of the changes in albumin on 15th and A1-globulin occurred on 40th day and in haptoglobin only on 100th day after neutron irradiation.     

Effects of neutron and combined gamma irradiation of rats

The effect of single neutron irradiation (2 Gy) alone and combined with continuous gamma irradiation (6 Gy accumulated during 10.5 days) was studied on the survival of rats and on nucleic acids both in the lymphoid organs and testes. After neutron irradiation alone the most profound changes in lymphoid organs and testes were found on the third and within the days 28-60, respectively. Regeneration has been undergone at a relatively fast rate. Continuous irradiation subsequent to neutron irradiation deepened only slightly the extent of the initial changes. The effect of combined irradiation manifested mainly a later times in marked slowing down of regeneration.     

Changes in cellularity, CFU-S number and chromosome aberrations in bone marrow and blood of rats after neutron and continuous gamma irradiation

Changes in the hematopoietic bone marrow of rats were observed after single wholebody neutron dose of 2 Gy and combined single neutron (2 Gy) and continuous gamma (6 Gy, daily dose rate of 0.5742 Gy) irradiation. Neutron irradiation significantly reduces the number of karyocytes in the bone marrow including CFU-S and induces the extensive cytogenetic damage. The following continuous gamma irradiation does not intensify the primary damage, but maintains the CFU-S and cellularity values at a decreased level for the whole time of irradiation. Recovery of the damage begins only after the termination of continuous irradiation; its course is similar to that after single neutron irradiation. The influence of combined effect of neutrons and gamma rays is nevertheless manifested in later periods after the irradiation by reduction in the total CFU-S number in the bone marrow.     

RNA and DNA changes in the bone marrow and blood of rats after neutron and continuous gamma irradiation

Quantitative changes in nucleic acids and DNA synthesis in the bone marrow and blood were followed after a single neutron irradiation with the dose of 2 Gy alone and combined with subsequent continuous gamma irradiation up to accumulated dose of 6 Gy. The pattern of changes after neutron exposure was similar as after other kinds of ionizing radiation. Additional continuous gamma irradiation affected mainly the rate of regenerative processes.     

Morphologic alterations in rat bone marrow and spleen after neutron and gamma irradiation

Morphologic alterations were studied in rat bone marrow and spleen after wholebody neutron irradiation (2 Gy dose). Neutron irradiation causes damage of hemapoietic organs changing their morphological structure already in the first hours after irradiation. The damage is further intensified reaching its maximum on 3rd day. Recovery of the hemopoiesis in the bone marrow and spleen begins approximately on 5th day being complete by 15th to 21st day after irradiation. Continuous gamma irradiation for 10.5 days following single neutron irradiation (total accumulated dose of 6 Gy, daily input dose of 0.574 Gy) results in prolonged inhibition of the hemopoietic activity until termination of the irradiation. Reparation of the damaged bone marrow is seen only on about day 5 after cessation of continuous irradiation; this implies that continuous irradiation following neutron irradiation delays the onset of reparative processes by approximately 5 days. In the spleen reparation of erythropoiesis begins already during the irradiation.     

X射线对人外周全血细胞nm23-H1基因表达的影响

目的 应用实时荧光定量反转录PCR的方法,分析不同剂量X射线对人外周全血细胞nm23-H1基因表达的影响,探讨运用nm23-H1基因表达变化作为电离辐射生物剂量计的可行性。 方法 采用X射线照射人外周全血细胞,于不同剂量(0～5 Gy)照射后不同时间点(0、6、12和24 h)收集细胞提取总RNA,并反转录为cDNA,利用实时定量PCR检测不同剂量照射后nm23-H1基因表达变化,分析其剂量-效应关系及时间-效应变化。结果 照后0 h,各剂量组之间nm23-H1基因表达变化差异无统计学意义(F=0.478,P> 0.05),照后6 h,在1～3 Gy照射剂量范围内,nm23-H1基因表达水平随剂量增加有增高的趋势(F=15.064,P<0.05),照后12 h,在1～5 Gy照射剂量范围内,nm23-H1基因表达水平随剂量增加而增高(F=3.435,P<0.05);照后24 h,各剂量组之间差异无统计学意义(F=0.444,P>0.05)。0、4 和5 Gy照射后,nm23-H1基因表达水平随时间的推移降低 (F=8.636、4.112、5.411,P<0.05);1 Gy照射后,不同时间点nm23-H1基因表达水平差异无统计学意义,仅12 h的 nm23-H1基因表达水平与0 h的表达水平差异有统计学意义(t=-2.527,P<0.05);2和3 Gy剂量照射后,nm23-H1基因表达水平均于24 h时降至最低点(F=12.517、6.622,P<0.05)。结论 电离辐射可诱导人外周血nm23-H1基因的表达改变,该基因的表达变化具有作为电离辐射生物剂量计应用于核辐射事故早期生物剂量估算的潜能。     

低剂量率裂变中子照射对大鼠外周血淋巴细胞亚群的影响

目的 探讨低剂量率中子长期照射对大鼠外周血细胞亚群的影响。方法 96只雄性大鼠分为对照组和照射组,照射组每天用低剂量率中子²⁵²Cf(吸收剂量率为0.35 mGy/h)照射20.5h,在照射的第14、28、42、56和70天(累积剂量分别为0.1、0.2、0.3、0.4和0.5 Gy)及停止照射后第35天各取8只大鼠,用血细胞计数仪检测大鼠外周血WBC、用流式细胞仪检测外周血CD4⁺CD3⁺、 CD8⁺CD3⁺、CD45RA⁺/CD161α⁺亚群的变化。结果 累积剂量为0.3、0.4及0.5 Gy时WBC明显低于对照组(P<0.05),停止照射后35 d,WBC显著低于对照组(P<0.01);累积剂量为0.1、0.3、0.4、0.5 Gy及停止照射后35 d,外周血CD4⁺CD3^-细胞比例显著高于对照组(P<0.01或<0.05);累积剂量为0.2和0.3 Gy时CD8⁺CD3^-细胞比例显著高于对照组(P<0.05或P<0.01)。而累积剂量为0.1 Gy时的CD4⁺CD3⁺细胞比例及0.1和0.2 Gy时的CD8⁺CD3⁺细胞比例明显高于同一天对照组(P<0.01或<0.05)。另外,低剂量率中子长期照射可使累积剂量为0.2~0.3 Gy的外周血NK细胞(CD161α⁺ CD45RA^-)显著升高,累积剂量为0.1~0.5 Gy及停止照射后35 d照射组的外周血B细胞(CD161α^- CD45RA⁺)比例明显下降。结论 低剂量率裂变中子长期照射可使外周血淋巴细胞TCR基因突变,使大鼠外周血WBC减少,淋巴细胞中B细胞减少,NK细胞细胞比例升高,这种变化在停止照射后一段时间仍可能难以恢复。     

低剂量γ射线辐照对血清抗氧化系统的兴奋效应

目的：探讨低剂量γ射线辐照人全血对血清抗氧化酶活性的影响。方法：20份人全血,以剂量为1Gy的γ射线进行辐照,吸收剂量率为17Gy/min,分别于照射前及照射后1、2h取样检测血清中总抗氧化能力（T—AOC）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH—Px）、过氧化氢酶（CAT）、谷胱甘肽还原酶（GR）活力及还原性谷胱甘肽（GSH）、丙二醛（MDA）含量。结果：离体全血在剂量为1Gy γ射线照射后1h,可见血清中GSH含量升高,MDA含量降低及T—AOC、SOD、GR、GSH—Px、CAT活性升高,且均与照射前比较有显著差异（P〈0．01）。经γ射线照射2h后,除SOD活性与照射后1h差异无显著性外,MDA含量进一步降低,GSH含量及T—AOC、GR、GSH—Px及CAT活性进一步升高,与照射后1h比较有显著差异（P〈0．01）。结论：低剂量γ射线辐照能明显提高血清抗氧化能力,即可诱导抗氧化系统的兴奋效应。