Fig. 5

MGF overexpression preserved age-related Olfactory deficits and enhanced neural stem cell proliferation and differentiation. a Three groups of MR mice were separately fed with IPTG inducer in the daily water beginning at 1,3,12 month old (MR-1,MR-3,MR-12) and terminated at the age of 24 months old followed by function analysis and in vivo neurogenesis analysis. b Among all these 24-month-old mice, mice with constitutive overexpression of MGF throughout life (M-24) or induced overexpression of MGF from 1 month (MR-1) or 3 months (MR-3) of age had significantly improved olfactory function compared to the control mice of MR dtg mice (MR-24) with water (no IPTG) or MR dtg mice that began IPTG induction at 12 months (MR-12). MR-1, MR-3 and M-24 mice found buried food more rapidly. There was no difference among other control groups (n = 4–8 mice per group; bars represent mean ± SEM). The newborn neurons in olfactory bulb were quantitated after immunofluorescence stains. c Representative confocal images showing BrdU+ proliferating cells in the SVZ (d) differentiated mature granular neurons in olfactory bulb. e Quantification of total BrdU+ cells of olfactory bulb (f) and the percentage of newly generated granular neurons (BrdU+/NeuN+) from the total BrdU+ proliferating cells in olfactory bulb were quantitated. Early induced overexpression of MGF in the brain beginning at 1 month and 3 months had significantly enhanced the total number of BrdU+ proliferating cells and the average percentage of newly differentiated granular neurons (BrdU+/NeuN+) in the olfactory bulb by the age of 24 months. However, later overexpression of MGF induced at the age of 12 months had increased the percentage but not significantly compared to the control mice(R mice). Green(BrdU), Red(NeuN), Blue(Nuclear). (Error bars indicate ± SEM. **p < 0.01. Scale bar = 50 um