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Raising pH in the stomach lumen does not limit damage progression at the gastric epithelial surface following microscopic lesions
Author(s) -
Demitrack Elise Susan,
Montrose Marshall H
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1318-c
Subject(s) - exfoliation joint , ph indicator , chemistry , extracellular , biophysics , intracellular ph , gastric mucosa , stomach , cell damage , biochemistry , materials science , biology , nanotechnology , graphene
We have shown that during superfusion of the gastric surface with pH 3 solution, the response to microscopic (two‐photon) photodamage includes rapid cell exfoliation and coincident epithelial repair. Our goal here is to ask if exfoliation is due to the stress of a highly acidic luminal pH. Methods: To measure surface pH, gastric mucosa of anesthetized mice was ratio imaged (Zeiss two‐photon microscope) while the stomach was perfused with lightly buffered pH 3 saline plus Cl‐NERF, or pH 7 saline plus BCECF. A 2‐3 cell region of the epithelial surface (~ 225 μm 2 ) was photodamaged by two‐photon laser light (710nm, 0.4 W for 5‐8 s). Photodamage was monitored through the loss of NAD(P)H autofluorescence, and cellular uptake of extracellular pH dye. Results: At pH 3, initial surface pH values averaged 3.08 (n=2), and reached maximum pH value of 3.66 after damage. At pH 7, initial pH values were 6.4 ± 0.3 (n=5), and reached maximum values of 6.6 ± 0.3 after damage. At pH 3 and pH 7, initially damaged areas were similar (90 μm 2 at pH 3, n=2; 130 ± 124 μm 2 at pH 7, n=4). Damage expanded to adjacent cells, resulting in a maximally damaged area of 1434 μm 2 at pH 3 and 2115 ± 575 μm 2 at pH 7. By 15 ± 10 min, cell exfoliation was complete at both luminal pH values. Conclusion: Expanding damage and exfoliation occur at widely variable luminal pH, suggesting the process is an intrinsic property of the gastric epithelium that does not require an acidic environment. Supported by NIH RO1 DK54940.