[A comparison study between D-galactose treated mice and natural aging mice]

To explore the feasibility of D-galactose treated mice's implication in aging related study by comparing the difference of all kinds of index between D-galactose treated mice and normal aging mice.

Kunming mice were used as test animals, which were divided into three groups: D-galactose treated group, normal aging group and young mice group (as control group). Immunology index, including delayed-type hypersensitivity, half hemolysis concentration, plaque forming cell, NK cell activity, were detected. Biochemical index, including malondiadehycle (MDA) concentration, superoxide dismutate (SOD) activity, SOD mRNA and protein, behavior index (mouse water maze test and neurotransmitter) and pathology (conventional pathology and immune histo-chemistry) were also determined.

Compared with control group, humoral immunity of normal aging mice was obviously lower, but humoral immunity of D-galactose treated mice showed no difference. Compared with control group, SOD activity was higher and MDA concentration was lower in both D-galactose treated mice and normal aging mice. Behavior tests demonstrated that swimming time extended in different time phase in normal aging mice compare with control group, D-galactose treated group, however, showed no obvious difference. Adrenaline and tissue dopamine in brain tissue of normal aging mice decreased compared with control group, but D-galactose treated mice expressed no difference. And neurotransmitter changes were in accordance with behavior tests. The expression of SOD mRNA level, SOD activity and protein reduced in normal aging group and D-galactose group, compared with control group, which suggested that the downexpression of SOD mRNA was the main cause to the depressed SOD protein expression level and activity.

D-galactose treated mice were similar to natural aging mouse in some aspects, but there was still big difference between them in immunology and behavior index. D-galactose treated mice is caused by chemical damage and this model is hard to reflect real physiology and biochemistry changes, so it is not a ideal model for immunological and behavioral aging study.