Table 1. Mitochondrial mass and activity in P40/50 and P50/70 populations.

Parameter	P40/50	P50/70	p-value
Mitochondrial protein concentration (μg/ml)/106 cells	62.02 ± 25.2	60.36 ± 33.0	0.948
JC-1 red fluorescence/106 cells (relative fluorescence intensity)	637 ± 178	365 ± 50	0.062

Results are given as mean ± SD, n = 3. For statistical analysis Student’s t-test was performed. As a measure of mitochondrial density/mass, protein concentration of isolated mitochondria fractions was determined and related to the cell number. The functional integrity of mitochondria was assessed by measurement of the electrochemical proton gradient (Δψ_m) of the inner mitochondrial membrane using JC-1.