Fig. 1: Measurement of CYP induction by Raman microscopy.

a Average Raman spectra of HepaRG cells treated with (red) or without (gray) rifampicin (RIF). The Raman shifts of 1370 cm⁻¹ and 1636 cm⁻¹ increased after treatment with RIF for 48 h; enlarged in the insets. b Reconstructed Raman images at 600 cm⁻¹, 675 cm⁻¹, 1000 cm⁻¹, 1370 cm⁻¹, and 1636 cm⁻¹, which can be assigned to cyt c, cyt b₅, phenylalanine, oxidized CYPs, and LS CYPs, respectively. The comparison of these cellular components demonstrated that 1370 cm⁻¹ and 1636 cm⁻¹ increased after CYP induction. Scale bars, 20 µm. c Immunofluorescence staining of cyt b₅ and CYP3A4 at the same positions as Raman measurement. Scale bars, 20 µm. d Western blots of CYP3A4, cyt c, cyt b₅, and β-action. e CYP3A4 activity assay indicates CYP induction after RIF treatment. Error bars indicate SD between triplicates. ***P < 0.001.