细胞贫血,动物实验 z-bo 2020-08-12 468

　　Temperature-sensitive L cell line mutation mouse (ts) model: Two temperature-sensitive mouse mutation L cells, ts A1, S9 and ts C1, were isolated by Thompson (1971). Cytological studies have shown that these two ts cell mutations Can cause similar morphological changes. When moving from 34°C to 38.5°C, the cells and cell nuclei were significantly enlarged. After culturing at 34°C for 24 hours, the nuclear chromatin is denser, the nuclear staining is deeper, and the transparent area between the chromatin is very small. After being cultured at 38.5°C for 48 hours, the chromatin was reticulated and evenly dispersed, with lighter nuclear staining and more nucleoli, similar to the morphology of human macrophages. These morphological changes are reversible. When the cell returns to 34°C, the half-retained DNA replication can be restored, and the morphology will be restored to its original state.

　　[Result analysis] Human megaloblastic anemia is induced by drugs or caused by folic acid and vitamin B12 deficiency, both of which are the result of DNA synthesis defects. The molecular basis of this defect has not been elucidated. The megaloblastic anemia of ts mouse L cell line with defective DNA synthesis can continuously depolymerize chromatin and nuclear growth like normal cells, but chromatin reagglutination is blocked, resulting in a morphological appearance Accumulation of small, evenly distributed chromatin. Due to defects in DNA synthesis, single-stranded DNA fragments are formed, which can explain the chromosomal abnormalities such as non-polyploid, chromosome cracks and breaks, and acentric fragments seen in megaloblastic anemia.