Presentation Preparation of a Younger Selenium-Deficient Mouse Model

上野, 恵美  ,  下川, 卓志  ,  中西, 郁夫  ,  松本, 謙一郎

Relatively young (8-week-old) selenium deficient (SeD) mouse model was prepared using torula yeast based SeD diet. Selenium (Se), which is an essential trace element, has important roles in the biological redox regulation system as the catalytic center of glutathione peroxidases (GSH-Px). The GSH-Px can reduce hydrogen peroxide (H2O2) to water with the expense of reduced form glutathione (GSH). Up to this point, SeD mouse models reported were prepared by starting SeD diet from weanling mice or later, and relatively older (> 8-weeks-old) SeD model mice can only be available. In this experiment, several different timings for starting SeD diet were demonstrated and weekly time course of GSH-Px activities after starting SeD diet were monitored.Mice were fed on the torula yeast based SeD diet (F2SeDD, Oriental Yeast Co., Ltd., Tokyo) and ultra-pure water (mili-Q water). Several different timings for starting SeD diet were demonstrated. SeD diet was started from 15th day of pregnancy (SeD-trial-P), 1 day after giving birth (SeD-trial-B), or 2 weeks after giving birth (SeD-trial-2w) on the dams and weanling mice were fed SeD diet until the experiment. Otherwise healthy 4 or 8 weeks old mice were purchased and simply fed on SeD diet for several weeks (SeD-trial-4w and SeD-trial-8w). Se-control (SeC) mice were bred under identical condition of SeD group, except that 1.5 mg Se-compounds-mixture (seleno-L-methionine : sodium selenate : sodium selenite = 1.22 : 0.15 : 0.13 mg, which is 8 : 1 : 1 as molar ratio) was added to 1 L of drinking water (0.64 mg/L of Se). Weekly time course of liver GSH-Px activities after weaning were monitored. GSH-Px activity in the liver homogenate was measured based on the method described by Paglia and Valentine (1) with some modifications.Postweaning start of SeD diet (SeD-trial-4w and SeD-trial-8w) could give relatively older (> 8-week-old) SeD mice model. SeD-trial-P, which is the procedure reported for a SeD rat model, (2) and SeD-trial-B procedures could not prepared SeD mouse model due to neonatal death. Number of live births confirmed was 5.0 ± 0.8 (n = 4) and 4.2 ± 1.1 (n = 5) for SeD-trial-P and -B mothers, respectively. However, the newborn mouse cubs could survive less than 21 days for SeD-trial-P and 13 days for SeD-trial-B groups. Those results suggest that Se is quite necessary to give normal birth and healthy growing of mouse cubs. Starting SeD diet to the mother mouse from 2 weeks after giving birth (SeD-trial-2w) could give 8-week-old SeD mouse model. The liver GSH-Px activities of 8-week-old SeD-trial-2w group were almost non, while the normal group (fed on normal diet, MB-1) and SeC group (fed on SeD diet + 1.5 mg Se in drinking water) could keep GSH-Px activity.This SeD-trial-2w mouse model can be proposed for a practical H2O2-induced oxidative stress model for future experiments.1.D. E. Paglia, and W. N. Valentine. J. Lab. Clin. Med. 1967, 70, 158–169.2.K. Matsumoto, K. Endo, and H. Utsumi. Biol. Pharm. Bull. 2000, 23, 641–644.

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