Effects of age and jet lag on D-galactose induced aging process.

Chronic administration of D-galactose (D-gal) is a useful method for establishing a model of natural aging. However, whether animal age or jet lag influences the D-gal-induced aging process has not been investigated. To clarify these issues, ICR male mice were given a daily injection of D-gal (500 mg/kg bw) for 7 wks. D-gal-treatment caused a significant decrease only in the transcript level of Cat gene in the 6-wk-old mice, whereas it significantly reduced the expression of Cat and Sod1 genes and of Cat, Gpx1, Sod1 and Sod2 genes in the 12- and 22-wk-old group, respectively, suggesting that D-gal induced aging process was greatly dependent on the age of mice. Mice receiving both D-gal and jet lag exhibited larger decreases in the expression levels of above four genes in liver as compared with that of either group singly, indicating a synergistic effect of jet lag and D-gal on the aging process.