Differential Effects of Silibinin A on Mitochondrial Function in Neuronal PC12 and HepG2 Liver Cells

Figure 3

Effects of silibinin A (SIL A) on mitochondrial function in HepG2. (a) ATP level (% of medium control). Cells were incubated with SIL A (S) at different concentrations (25–150 μM) for 24 h and measured against control cells treated with DMSO (data not shown). DMSO results showed no significant difference compared to the medium control. (b) ATP level (% of medium control) of cells injured via the addition of 5 mM SNP 1 hour after the initial incubation with test substances. Cells were incubated for a total of 24 h. (c) MMP level (% of medium control). Cells were incubated with 50 or 150 μM SIL A for 24 h and measured against control cells treated with DMSO (data not shown). DMSO results showed no significant difference compared to the medium control. (d) MMP level (% of medium control) of cells injured via the addition of 5 mM SNP 1 hour after the initial incubation with test substances. Cells were incubated for a total of 24 h. (e) Respiration of HepG2 cells after 24 hours of incubation with the test substance or control. Measured data indicate the oxygen consumption of cells in an Oxygraph-2k (Oroboros). Cells were incubated with 25 μM SIL A (S) and compared against control cells treated with DMSO (co). Activity of OXPHOS complexes was assessed via the addition of several substrates, inhibitors, or uncouplers. Which substance was added in which stage of the experiment is indicated by the placement of “+.” Dig = the addition of digitonin; CI_(L) = leak respiration of complex I; CI_(P) = coupled respiration using only complex I substrates; CI&CII_(P) = physiological respiration; CI&CII_(L) = leak respiration of complexes I and II; CI&CII_(E) = uncoupled respiration using maximum CI&CII activity; CII_(E) = uncoupled respiration using complex II substrates only; CIV_(E) = uncoupled respiration using only CIV after complex III inhibition and CIV activation using an electron donor. (f) Citrate synthases activity.Data are displayed as the . . Statistical significance was tested via one-way ANOVA and Tukey’s post hoc test in (b). In (a, c–f), statistical significance was tested via Student’s -test of the treatment group versus the DMSO control (, , , and ).

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