Figure 3.

Age-related changes in the number and quality of mitochondria in brain neurons

(A) The number of mitochondria in the neuronal cell body did not significantly change during aging. More than four brain hemispheres from flies of each age were analyzed using transmission electron microscopy (TEM), and the numbers of mitochondria in more than 30 cells in each hemisphere were counted. Representative images are shown, with the mitochondria highlighted in orange.

(B) The ratio of the number of abnormal mitochondria to the total number of mitochondria increased in the cell body during aging. More than four brain hemispheres from flies of each age were examined using TEM, and more than 30 cells were analyzed in each hemisphere. The number of mitochondria containing vacuoles or disorganized cristae (asterisks) was counted. (mean ± SE, n = 4–5; n.s., p > 0.05, ∗p < 0.05; Student's t-test).

(C) Neuronal overexpression of hGlut3 did not affect the age-associated changes in mitochondria in the brain. The mitochondrial density (left) and the ratio of the number of abnormal mitochondria to the total number of mitochondria (right) in neurons expressing hGlut3 in the Kenyon cell region of the brains were analyzed under TEM 50 days after eclosion (mean ± SE, n = 4–6; n.s., p > 0.05; Student's t-test).