Figure 13 - H₂O₂ in LES epithelial and circular muscle cells.

H₂O₂ levels were examined by confocal microscopy using dihydrorhodamine (DHR 123) as a probe for measurement of intracellular H₂O₂. Left panel: In untreated epithelial cells (control) H₂O₂ levels were low and did not change in response to HCl or IL-6. An H₂O₂-treated epithelial cell is shown as a positive control. H₂O₂ is membrane permeable, and in the H₂O₂-treated cell, it penetrates the cytoplasm, demonstrating the adequacy of the technique in detecting cytoplasmic H₂O₂. Right panel: In normal LES smooth muscle cells (control) H₂O₂ levels were low and were not affected by HCl. Treatment with supernatant of HCl-filled mucosal sac (mucosa-HCl supernatant), or with supernatant of mucosa from esophagitis animals (esophagitis mucosa supernatant), increased H₂O₂ in muscle cells. Similarly, treatment with IL-6 or platelet-activating factor (PAF) caused an increase in cytoplasmic H₂O₂ (Source: Cheng et al.,¹⁰⁵ with permission from the American Physiological Society.)