The use of transgenic and mutant mice to study oxygen free radical metabolism
The use of transgenic and mutant mice to study oxygen free radical metabolism
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DOI：
10.1111/j.1749-6632.1999.tb07820.x
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发表时间：
1999-01-01
期刊：
影响因子：
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通讯作者：
Epstein, CJ
中科院分区：
文献类型：
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作者：
Huang, TT;Carlson, EJ;Epstein, CJ
为了区分锰超氧化物歧化酶（MnSOD）和胞质铜锌超氧化物歧化酶（CuZnSOD）的作用，采用同源重组的方法将小鼠MnSOD基因（Sod 2）失活。具有CD 1（远交）遗传背景的Sod 2-/-小鼠在出生后10天内死亡（平均5.4天），具有复杂的表型，包括扩张型心肌病、肝脏和骨骼肌中脂质蓄积、代谢性酸中毒和酮症以及琥珀酸脱氢酶严重降低（复合物II）和乌头酸酶（TCA循环酶）活性，并且在较小程度上，在其他器官中。这些研究结果表明，MnSOD是必需的，以保持线粒体酶的完整性，容易直接失活的超氧化物。另一方面，Lebovitz等人报道了在具有不同表型的混合C57 BL/6和129 Sv背景下独立衍生的MnSod敲除小鼠（Sod 2 tmlLeb）。由于遗传背景的差异是表型差异的最可能的解释，因此将两个突变系杂交到不同的遗传背景中以进行进一步分析。为了研究Sod 2 tmlLeb小鼠CD 1背景的表型，将Sod 2 tmlLeb小鼠与CD 1杂交两代，然后将-/+小鼠相互杂交以产生-/-小鼠。CD 1 Leb的寿命分布向左移动，表明在CD 1背景下寿命缩短。此外，CD 1 Leb小鼠在早期阶段发生代谢性酸中毒，如用CD 1Cje观察到的。当将Sod 2 tmlCje置于C57 BL/6 J（B6）背景下时，发现-/-小鼠在妊娠中期或出生后前4天内死亡。然而，当B6 Cje小鼠与DBA/2 J（D2）杂交产生B6 D2 F2Cje小鼠时，观察到与Lebovitz等人描述的表型完全不同的表型。F2 Sod -/-小鼠能够存活长达18天，存活超过15天的动物显示出神经异常，包括共济失调和癫痫发作。他们的心脏没有像CD 1小鼠那样受到严重影响，神经退行性变而不是心脏缺陷似乎是死亡的原因。
To distinguish the role of Mn superoxide dismutase (MnSOD) from that of cytoplasmic CuZn superoxide dismutase (CuZnSOD), the mouse MnSOD gene (Sod2) mas inactivated by homologous recombination. Sod2 -/- mice on a CD1 (outbred) genetic background die within the first 10 days of life (mean, 5.4 days) with a complex phenotype that includes dilated cardiomyopathy, accumulation of lipid in liver and skeletal muscle, metabolic acidosis and ketosis, and a severe reduction in succinate dehydrogenase (complex II) and aconitase (a TCA cycle enzyme) activities in the heart and, to a lesser extent, in other organs. These findings indicate that MnSOD is required to maintain the integrity of mitochondrial enzymes susceptible to direct inactivation by superoxide. On the other hand, Lebovitz et al. reported an independently derived MnSod null mouse (Sod2tmlLeb) on a mixed C57BL/6 and 129Sv background with a different phenotype. Because a difference in genetic background is the most likely explanation for the phenotypic differences, the two mutant lines were crossed into different genetic backgrounds for further analyses. To study the phenotype of Sod2tmlLeb mice CD1 background, the Sod2tmlLeb mice were crossed to CD1 for two generations before the -/+ mice were intercrossed to generate -/- mice. The life span distribution of CD1Leb was shifted to the left, indicating a shortened life span on the CD1 background. Furthermore, the CD1Leb mice develop metabolic acidosis at an early stage as was observed with CD1Cje. When Sod2tmlCje was placed on C57BL/6J (B6) background, the -/- mice were found to die either during midgestation or within the first 4 days after birth. However, when the B6Cje mere crossed with DBA/2J (D2) for the generation of B6D2F2Cje mice, an entirely different phenotype, similar to that described by Lebovitz et at, was observed. The F2 Sod -/- mice were able to survive up to 18 days, and the animals that Lived for more than 15 days displayed neurological abnormalities including ataxia and seizures. Their hearts were not as severely affected as were those of the CD1 mice, and neurological degeneration rather than heart defect appears to be the cause of death.