Fig. 6.

Per1 Protects Mitochondrial Function from Fasting-Induced Oxidative Stress. A, B) The expression profiles of clock genes in the livers (A) and intestines (B) of WT mice in fasting stress compared to those in feeding at ZT0. Quantitative RT-PCR was performed for analyzing mRNA level in fed (white) and fasted (black) WT mice (n = 5 per group, *p < 0.05, **p < 0.01 compared with fed group). C, D) Western blot analysis of PER1 protein level in livers (C) and intestines (D) of WT mice in fasting stress compared to those in feeding at ZT1 (n = 3). β-actin was used as internal control. E, F) GPx activity of the livers (E) and intestines (F) from WT and Per1^−/− mice were measured under fasting condition (n = 5 per group, *p < 0.05 compared with WT group). G, H) Peroxide levels of the livers (G) and intestines (H) from WT and Per1^−/− mice were measured under fasting condition (n = 5 per group, *p < 0.05 compared with WT group). I) TEM analysis of the geometry of mitochondria in livers and intestines from fasting WT and Per1^−/− mice at ZT0, n = 3. Bar = 0.5 μm. J, K) The percentage of mitochondrial less than 500 nm in length (left) and total mitochondrial lengths (right) calculated from EM images in fasted WT and Per1^−/− mouse livers (J) and intestines (K) at ZT0 (n = 3, **p < 0.01, ***p < 0.001, Per1^−/− versus WT group). Throughout, all data were expressed as the mean ± SEM and male mice for all experiments were maintained on standard chow. Analyses were performed using two-tailed Student's t-test for A and B, E-H, J and K.