Polaprezinc protects gastric mucosal cells from noxious agents through antioxidant properties in vitro.
BACKGROUND
Polaprezinc has been shown to exert an anti-oxidant property in a tube experiment, protect gastric mucosa from experimental ulcerations in vivo, and accelerate the healing of gastric ulcer in humans.


OBJECTIVE
To examine a possible protective effect of polaprezinc on oxidant-mediated injury in primary monolayer cultures of rat gastric fundic mucosa.


METHODS
Cytotoxicity was quantified by measuring 51Cr release. Whether or not polaprezinc exerts an antioxidant property was investigated by determining the effect of this agent on hydrogen peroxide (H2O2)-induced injury. The effects of polaprezinc on superoxide (O2-. ) generation as well as on ethanol (EtOH)-induced injury were also examined. Generation of O2-. was assessed by the reduction in cytochrome c.


RESULTS
H2O2 caused a time- and dose-dependent increase in 51Cr release. The dose-response curve of 51Cr release by H2O2 shifted to the right in the presence of polaprezinc. Polaprezinc, at submillimolar concentrations, prevented H2O2-induced 51Cr release. EtOH also caused a dose-dependent increase in 51Cr release, which was prevented by the addition of polaprezinc. The incubation of cells with EtOH caused an increase in cytochrome c reduction, as the concentrations of EtOH increased. Polaprezinc inhibited EtOH-induced cytochrome c reduction. Protection by polaprezinc was microscopically associated with the prevention of monolayer disruption.


CONCLUSIONS
Polaprezinc is antioxidative and directly protects gastric mucosal cells from noxious agents through its antioxidant properties in vitro. This finding may provide the theoretical basis for the usage of an antiulcer drug with antioxidant properties for the treatment of gastric inflammation, such as that induced by ethanol.
Hiraishi
H
H
Second Department of Internal Medicine, Dokkyo University School of Medicine, Mibu, Tochigi, Japan.
Sasai
T
T
Oinuma
T
T
Shimada
T
T
Sugaya
H
H
Terano
A
A
D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D002336:Carnosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D000431:Ethanol / Q000633:toxicity; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000633:toxicity; D008297:Male; D008858:Microscopy, Phase-Contrast; D009942:Organometallic Compounds / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017967:Zinc Compounds; D019287:Zinc Sulfate / Q000494:pharmacology
D000897:Anti-Ulcer Agents; D000975:Antioxidants; D003574:Cytochrome c Group; D009942:Organometallic Compounds; D017967:Zinc Compounds; C061957:polaprezinc; D000431:Ethanol; D019287:Zinc Sulfate; D002336:Carnosine; D006861:Hydrogen Peroxide