[Optimization of Mouse Model of Aplastic Anemia Induced by Pan T Lymphocytes Combined with Irradiation].

AbstractObjective: To establish an acquired aplastic anemia animal model for investigating the function of T lymphocyte and the pathogenesis and treatment of aplastic anemia(AA). METHODS: To establish the acquired aplastic anemia mouse model through the X-ray irradiation in combination with lymphocytes injection. AA Group: the purified Pan T lymphocytes from the spleen of C57BL/6J mice were enriched and injected to the mice through tail vein(5×106), the CB6F1 mice were exposed to 3,4 and 5 Gy X-ray irradiation; TBI Group: the CB6F1 mice were exposed to 3,4 and 5 Gy X-ray irradiation, and were injected with the same volume of PBS buffer; Control group: the CB6F1 mice were only injected with the same volume of PBS buffer. The peripheral blood routine was examined and the number of nucleated cells in bone marrow were calculated；the hematopoiesis changes in bone marrow was examined；flow cytometry was used to examine the distribution of T lymphocytes in bone marrow, and it also used to examine the apoptosis of bone marrow cells and the differentiation of spleen T lymphocytes. RESULTS: Compared with 4, 5 Gy irradiated mice in AA groups, the survival time of 3 Gy irradiated AA groups was significantly prolonged. 3, 4 and 5 Gy X-ray irradiation combined with Pan T lymphocyte injection could successfully induced severe reduction of red blood cells, blood neutrophils, and platelets, severe reduction of bone marrow nucleated cells, severe bone marrow hematopoietic failure, and the significant expansion of T lymphocytes ratio in the bone marrow. CD4+ and CD8+ T cells were both increased, but mainly on CD8+ T cells, and could promote the differentiation of T cells from naïve T cells to effector memory T cells. CONCLUSION: 3, 4 and 5 Gy X-ray irradiation combined with 5×106 pan-T cell injection could successfully induce acquired aplastic anemia through T lymphocyte hyperfunction. Compared with 4, 5 Gy irradiated AA group, the 3 Gy irradiated AA group shows significantly longer survival time, and the peripheral blood routine profile closely resembles the clinical manifestations of AA patients.

[Effects of partial root excision on the growth, photosynthesis, and antioxidant enzyme activities of maize under salt stress].

A pot experiment was conducted to study the effects of partial root excision on the growth of two maize cultivars (Zhengdan 958 and Denghai 9) throughout their growth period and the photosynthesis and leaf antioxidant enzyme activities at grain-filling stage under salt stress. Four treatments were installed, i. e., control (no salt), low salt (0.2% NaCl), moderate salt (0.4% NaCl), and high salt (0.6% NaCl). Under low salt stress, the grain yield of Zhengdan 958 and Denghai 9 with partial root excision was increased by 13.1% and 31.4%, respectively, as compared with that of the cultivars with no root excision. At jointing stage, the growth of the cultivars with partial root excision was restrained, the root- and shoot dry masses under the same salt stresses being lesser than those of the cultivars with no root excision, but the growth under the conditions of no salt and low salt recovered quickly. At milk-ripe stage and under no salt and low salt conditions, the root- and shoot dry masses, leaf area, total root length, total root surface area, root activity, leaf chlorophyll content, and ear leaf net photosynthetic rate, stomatal conductance, transpiration rate, and CAT and POD activities of the cultivars with partial root excision were significantly larger than those of the cultivars with no root excision, while the shoot diameter and ear leaf MDA content were in adverse. Moderate and high salt stresses had greater effects on the cultivars with partial root excision. The root- and shoot dry masses, root morphology, and photosynthesis indices of the cultivars with partial root excision were smaller than those of the cultivars with no root excision, so did the grain yields. Throughout the growth period of the cultivars, the growth of the cultivars with partial root excision depended on the salt concentration, i. e., was promoted under no and low salt, and inhibited under moderate and high salt conditions.