Figure 3.

rTg4510 neurons at 8.5 months of age have disrupted mitochondrial distribution, which can be ameliorated with transgene suppression. Box and whisker plots demonstrate percent cytoplasm occupied by mitochondria in soma (A) and neurites (B) of both untreated and doxycycline-treated 8.5-month-old rTg4510 and nonTg mice. As with the younger age group, neurites in the rTg4510, regardless of whether or not tau aggregates are present, are depleted of mitochondrial content whereas somatic mitochondrial distribution is only impacted with the presence of aggregated tau. In addition, 6 weeks of doxycycline treatment allows for recovery of mitochondrial distribution to near that of nonTg levels in both the somata and neurites. Representative array tomography images of mitochondrial distribution in single 70-nm sections of untreated 8.5-month-old rTg4510 (C) and doxycycline-treated 8.5-month-old rTg4510 (D) exhibit depletion of somatic mitochondrial content in Alz50+ cells, indicated by the arrow in C, whereas the arrowhead in D indicates recovery to near control levels following 6 weeks of doxycycline treatment. *P < 0.0001, **P < 0.005, and ***P < 0.0001. Scale bars = 10 μm.