Hyperbilirubinemia Protects against Aging-Associated Inflammation and Metabolic Deterioration

Figure 4

Bilirubin suppresses senescence and mitochondrial dysfunction in cultured primary fibroblasts. Rat primary fibroblasts were cultured for 18 passages in complete media with added bilirubin and then assayed for (a) senescence-associated β-galactosidase staining identified with inverted microscope; (b) whole cell respiration measured with respirometry; (c) mitochondrial DNA copy number per cell as a marker of mitochondrial abundance; (d) cellular production of H₂O₂ as a marker of ROS homeostasis; (e) lactate secretion to media as a marker of mitochondrial dysfunction; (f) intracellular ratio of 2-hydroxyglutarate/2-oxoglutarate as a marker of mitochondrial dysfunction. Data in panels (a, d, e, and f) expressed as % of controls, –8, overall significance measured with ANOVA, and in each panel; pairwise comparison with -test or Mann-Whitney rank sum test; significantly different from 0 μM; .

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