IL-1β induces co-localization of P-STAT-Ser727 with mitochondria in cultured DRG sensory neurons. DRG neurons were stimulated with IL-1β (10 ng/ml) for 30 min and then live cells loaded with MitoTracker deep red and then fixed and co-stained for P-STAT3-Ser727 and β-tubulin III. Confocal images of control (top panels) and IL-1β stimulated neurons (bottom panels) showing the individual channels and the co-localization coefficients between P-STAT3-Ser727 and MitoTracker deep red are shown. White arrows indicate neurons (e.g. positive for β-tubulin III) with P-STAT3-Ser727 and Mitotracker co-localization. Zeis LSM510 software was used to measure the co-localization coefficient; a threshold was set manually and a table of results was generated by the software, as described previously . Co-localization analysis was based upon review of 163 ± 4.1 neurons for each treatment of which 25.3 ± 5.6 neurons (n=3 replicates) exhibited high expression of P-STAT3-Ser727. The overall coefficient for co-localization with Mitrotacker deep red for the high expressing P-STAT3-Ser727 neurons was calculated as 0.432 ± 0.086 (as derived from the Zeiss LSM510 software).