Western-blot analysis of the inferior retinas after PONT.

<p>Each band from one animal. (A) The expression levels of TNF-α in the inferior retinas did not change after PONT at different time-points (P>0.05). (B) MnSOD level increased significantly 1 day after PONT and had returned to normal 4 days after PONT (*P<0.05) (C) P-JNK1 level did not change after PONT (P>0.05). P-JNK2/3 levels increased significantly from 1 day until 1 week after PONT (*P<0.05). (D) The levels of p-c-jun increased from 1 day until 1 week after PONT (*P<0.05). (n = 3 in each group.).</p

Behavioral Stress Fails to Accelerate the Onset and Progression of Plaque Pathology in the Brain of a Mouse Model of Alzheimer's Disease

<div><p>Conflicting findings exist regarding the link between environmental factors and development of Alzheimer's disease (AD) in a variety of transgenic mouse models of AD. In the present study, we investigated the effect of behavioral stress on the onset and progression of Aβ pathology in the brains of TgCRND8 mice, a transgenic mouse model of AD. One group of TgCRND8 mice was subjected to restraint stress starting at 1 month of age until they were 3 months old, while restraint stress in the second group started at 4 months of age until they were 6 months old. After 2 months of treatment, no differences in the soluble, formic acid extracted, or histologically detected Aβ deposition in the cortical and hippocampal levels were found between non-stressed and stressed mice. These results showed that restraint stress alone failed to aggravate amyloid pathology when initiated either before or after the age of amyloid plaque deposition in TgCRND8 mice, suggesting that if stress aggravated AD phenotype, it may not be via an amyloid-related mechanism in the TgCRND8 mice. These findings are indicative that plaque load per se may not be used as a significant criterion for evaluating the effect of stress on AD patients.</p></div

Schematic diagrams showing the procedures for the estimation of RGC survival.

<p>Rats were fed with PBS or LBP 1 week before CONT or PONT until sacrifice. (A) In CONT experiments, CONT was performed and then a piece of gelatin soaked with FG was placed close to the ON stump to label RGCs on day 0. Rats were sacrificed 1 week or 2 weeks after surgery. (B) In PONT experiments, SC labeling was performed 1 week before PONT and rats were sacrificed 1 week or 4 weeks after surgery.</p

Plasma corticosterone levels in the stressed TgCRND8 mice increased compared with that in their non-stressed controls at the age of 3 and 6 month-old.

<p>* indicates statistical differences when compared with their age-matched non-stressed controls at <i>p</i><0.01.</p

TUNEL staining in the inferior retinas after PONT.

<p>(A) The number of positive-staining cells increased significantly in the inferior retinas 1 week after PONT, compared with the normal retinas (P<0.01). There were no significant differences between normal and any other group. (B) The positive cells in the GCL of the inferior retina 1 week after PONT (red). The positive staining was located in the nuclei (C, D), which is shown with DAPI (blue). (n = 4, 3, 3, 5 and 4 in normal, 12 h, 1d, 4d and 1w groups respectively.).</p

Effects of LBP on survival of RGCs 1 week and 2 weeks after CONT.

<p>RGCs were labeled by FG. The arrows indicate microglia which were easily distinguished from RGCs and not counted. The blue arrowheads indicate RGCs. (A, C, D) Orally feeding of 0.1 mg/kg, 1 mg/kg and 10 mg/kg LBP showed no significant effects on the survival of RGCs 1 week after CONT (compared with PBS group) and no significant difference among the three different dosages of LBP groups was detected. (A, E, F) 1 mg/kg LBP showed no significant effects on the survival of RGCs 2 weeks after CONT (compared with PBS group). (n = 10, 8, 16, 12 in PBS, 0.1 mg/kg LBP, 1 mg/kg LBP, 10 mg/kg LBP groups sacrificed 1 week after CONT and n = 7 and 6 in PBS and 1 mg/kg LBP groups sacrificed 2 weeks after CONT.).</p

Western-blot analysis of the inferior retinas after treatment with PBS or LBP.

<p>(A) LBP increased the expression of MnSOD 1 day after PONT (*P<0.05). (B, C) LBP decreased the expression of p-JNK2/3 and p-c-jun (*P<0.05). (D) LBP did not change the expression of BDNF either 1 day or 1 week after PONT (P>0.05). (E) LBP increased the expression of IGF-1 1 day after PONT (*P<0.05), but did not change the expression of IGF-1 1 week after PONT (P>0.05). (n = 3, 3, 5 and 4 in PBS 1 day, LBP 1 day, PBS 1 week and LBP 1 week groups respectively.).</p

Restraint stress activated hypothalamic neurons in TgCRND8 mice.

<p>A–D: Cross sections of the brains stained with c-fos immunohistochemical staining in PVN (A and C) and SON (B and D) of TgCRND8 mice at the age of 4 months undergone restraint stress (A and B) and non-stress treatment (C and D). E: Quantitative analysis of number of c-fos immunoreactive nuclei in SON of stressed and non-stressed TgCRND8 mice. * indicates statistical differences when compared with their age-matched non-stressed controls at <i>p</i><0.01. Scale bar = 150 µm.</p

Effects of restraint stress on Aβ1-40 or Aβ1-42 levels in TgCRND8 mice.

<p>ELISA was used to measure Aβ levels in hippocampal tissues after completion of the restraint stress procedure. The data were expressed as means ± SEM. Restraint stress had no significant effect on Aβ levels in either soluble fraction or nonsoluble fraction.</p

The number of Thioflavin S-positive plaques/section in the brains of TgCRND8 mice at the age of 1, 3 or 6 month-old.

<p>The number of Thioflavin S-positive plaques/section in the brains of TgCRND8 mice at the age of 1, 3 or 6 month-old.</p