Effects of oxidant stress on inflammation and survival of iNOS knockout mice after marrow transplantation

In a model of idiopathic pneumonia syndrome after bone marrow transplantation (BMT), injection of allogeneic T cells induces nitric oxide (.NO), and the addition of cyclophosphamide (Cy) generates superoxide (O.) and a tissue-damaging nitrating oxidant. We hypothesized that.NO and O. balance are major determinants of post-BMT survival and inflammation. Inducible nitric oxide synthase (iNOS) deletional mutant mice (-/-) given donor bone marrow and spleen T cells (BMS) exhibited improved survival compared with matched BMS controls. Bronchoalveolar lavage fluids obtained on day 7 post-BMT from iNOS(-/-) BMS mice contained less tumor necrosis factor-alpha and interferon-gamma, indicating that.NO stimulated the production of proinflammatory cytokines. However, despite suppressed inflammation and decreased nitrotyrosine staining, iNOS(-/-) mice given both donor T cells and Cy (BMS + Cy) died earlier than iNOS-sufficient BMS + Cy mice. Alveolar macrophages from iNOS(-/-) BMS + Cy mice did not produce.NO but persisted to generate strong oxidants as assessed by the oxidation of the intracellular fluorescent probe 2',7'-dichlorofluorescin. We concluded that.NO amplifies T cell-dependent inflammation and addition of Cy exacerbates.NO-dependent mortality. However, the lack of.NO during Cy-induced oxidant stress decreases survival of T cell-recipient mice, most likely by generation of.NO-independent toxic oxidants.     

Improved method of ectopic transplantation of the whole spleen in mice

A simple and reliable technique has been developed for transplantation of the whole mouse spleen on the kidney. This technique ensures sufficient structural and functional recovery (transfer) of the original splenic microenvironments with a survival rate of 100%. The method allows counting the antibody-producing cells, as well as the spleen colony-forming units on the ectopic splenic territories. It may be used for studying hemopoietic and lymphoid microenvironments or for other special purposes.     

Effects of environmental temperature on thymus and spleen weights and lymphocytes in mice

Thymus and spleen weights and lymphocytes in the blood were examined in mice transferred from 22 degrees C to 12 degrees C or 32 degrees C environments. After the exposure to either environment, organ weights tended to decrease. In mice exposed to 12 degrees C, the number of WBCs and mononuclear cells and the ratio and the number of T cells decreased on day 1 and/or 3 after the exposure. The number of B cells also declined on day 3, but the ratio of B cells increased on days 3 and 7. In mice exposed to 32 degrees C, the number of WBCs and mononuclear cells and the number of T cells decreased on day 1 and increased on day 7 and/or 14. The ratio of T cells declined on days 1, 3 and 7, while that of B cells increased on day 3, and the number of B cells increased on day 7. These results show that wide variations in environmental temperature affect the weights of organs and the number of cells which act on immune responses in mice.     

Beneficial effects of moderate exercise on mice aging: survival, behavior, oxidative stress, and mitochondrial electron transfer

Moderate exercise in a treadmill (10, 15, and 20 cm/s, for 5 min each, weekly) from 28 to 78 wk of age extended male and female mice life span by 19 and 9% accompanied by 36 and 13% and 13 and 9% increased performance in behavioral assays (tightrope and T-maze tests) at 52 wk of age. Moderate exercise significantly decreased the aging-associated development of oxidative stress by preventing 1) the increase in protein carbonyls and thiobarbituric acid-reactive substances contents of submitochondrial membranes; 2) the decrease in antioxidant enzyme activities (Mn- and Cu,Zn-superoxide dismutase and catalase); and 3) the decrease in mitochondrial NADH-cytochrome-c reductase and cytochrome oxidase activities observed at 52 wk of mice age in brain, heart, liver, and kidney. These effects were no longer significant at 78 wk of age in mice. Moderate exercise, started at young age in mice, increased life span, decreased oxidative stress, and prevented the decline of cytochrome oxidase activity and behavioral performance at middle age but not at old age.     

模拟高原低氧环境对小鼠脾脏铁代谢的影响*

目的:探讨模拟海拔6 000 m高原低氧环境对小鼠脾脏铁代谢的影响。方法:将C57BL/6小鼠按体重随机分为常压常氧组(Nor)和低压低氧组(HH)。HH组小鼠放置于低压低氧动物实验舱内,模拟急性海拔6 000 m高原低氧环境,控制光照时间比大约12 h∶12 h。Nor组置于同等条件的常压常氧环境。HH组又分为低氧12 h组(HH-12 h)和3 d组(HH-3 d),对照组对应分为(Nor-12 h及Nor-3 d),每组9只小鼠。采用血常规检测、HE染色、组织铁染色、蛋白质免疫印迹(WB)、免疫组织化学(IHC)综合评价模拟高原低氧环境下小鼠脾脏铁代谢情况。结果:与相同时间点Nor组相比:①HH-12 h组小鼠红细胞数(RBC)、血红蛋白量(HGB)、红细胞压积(HCT)均无明显变化。HH-3 d组RBC、HGB及HCT均显著增加(P＜0.05),平均血红蛋白量(MCH)在HH-12 h和HH-3 d组均无显著变化。②与Nor-3 d相比,HH-3 d组小鼠脾脏明显增大,HE染色显示脾窦变窄,铁染色结果显示HH-3 d组脾脏红髓中铁含量明显增加。③WB结果显示,HH-3 d组低氧诱导因子1α(HIF-1α),转铁蛋白受体1(TfR1),铁输出蛋白(Fpn)表达均显著增加,而铁蛋白(Ft-L)的表达显著降低(P＜0.05);IHC结果也与WB结果一致,高原低氧暴露3 d后脾脏红髓TfR1、Fpn表达和分布均明显增多,Ft-L表达分布明显减少。结论:模拟海拔6 000 m高原低氧暴露3 d后小鼠脾脏截留处理RBC增多,脾索铁沉积,脾脏组织细胞内铁动员加速。高原低氧下脾脏铁代谢异常可能是引起高原低氧暴露下红细胞病理性增多甚至造成高原红细胞增多症的主要原因。