Effects of extracellular pH on restitution and proliferation of rabbit oesophageal epithelial cells.
OBJECTIVE
Exposure to luminal acid induces mucosal damage in the oesophagus. The extent and degree of interaction of acid with wound repair mechanisms of the oesophagus have not been explored.


METHODS
Rabbit oesophageal cells were isolated, cultured and exposed to different extracellular pHs for several periods of time. Cell mortality was studied in both isolated and primary cultures of these cells by cell flow cytometry using fluorochrome propidium iodide and LDH release. Subconfluent cell cultures were used to study proliferative responses determined by [3H]-thymidine incorporation into DNA. Restitution was studied in confluent monolayers wounded by mechanical denudation.


RESULTS
Isolated cells were resistant to acid when exposed to pH > 2 for 15 min. Cell proliferation increased with small pH decreases (7-6.5) if the period of exposure was less than 6 h, but was inhibited with lower pHs and/or longer periods of acid exposure. However, restitution was gradually inhibited with further pH decreases (6.5-3) and time of acid exposure (0.5-24 h).


CONCLUSIONS
The wound repair activities of oesophageal epithelial cells are deeply affected by even small decreases in pH. These findings may help to explain the need for profound acid inhibition in acid-related reflux oesophagitis.
Jimenez
P
P
Services of Gastroenterology, Unidad Mixta de Investigación, Hospital Clínico Universitario. Universidad de Zaragoza, Zaragoza. Spain.
Lanas
A
A
Piazuelo
E
E
Esteva
F
F
D000818:Animals; D002455:Cell Division; D002470:Cell Survival; D004847:Epithelial Cells / Q000473:pathology*; D004947:Esophagus / Q000473:pathology*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D011817:Rabbits; D013997:Time Factors; D014945:Wound Healing