Repression of the Antioxidant Pyrroloquinoline Quinone in Skin Aging Induced by Bmi-1 Deficiency

Figure 5

The effect of PQQ on DNA damage in the skin of Bmi-1^-/- mice. Representative micrographs of paraffin-embedded skin sections from 8-week-old WT, Bmi-1^-/-, and Bmi-1^-/-+PQQ mice stained immunohistochemically for (a) γ-H2AX and (c) 8-OHdG. The percentage of (b) γ-H2AX-positive and (d) 8-OHdG-positive cells was calculated and presented using image analysis. (e) Western blot analysis of protein level for p-CHK2 and γ-H2AX in the skin from the WT, Bmi-1^-/-, and Bmi-1^-/-+PQQ mice. β-Actin was used as a loading control. (f) p-CHK2 and (g) γ-H2AX protein levels relative to β-actin protein levels were determined using densitometric analysis and expressed relative to WT. Values are shown as the of seven determinations per group. and versus WT mice; ^& and ^&& versus Bmi-1^-/- mice.

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