We previously reported that NH2Cl induced extensive DNA fragmentation in gastric cells. Polaprezinc, a zinc-carnosine chelate compound, is reported to be a potent antioxidant in gastric mucosa. The present study was designed to examine whether polaprezinc could attenuate the NH2Cl-induced DNA damage. Gastric cell lines, MKN45, were exposed to NH2Cl in Ca2+-containing Hanks' balanced salt solution. DNA fragmentation was evaluated by photometric enzyme immunoassay for in vitro determination of cytoplasmic mono- and oligonucleosomes. Polaprezinc, L-carnosine, and zinc sulfate (ZnSO4) were added to the cell incubation medium to evaluate the inhibitory effect on the formation of cytoplasmic mono- and oligonucleosomes. Separately, the bleaching level of β-carotene with the addition of each test solution was evaluated to confirm the inhibitory effect against hypochlorous acid. Polaprezinc or L-carnosine, but not ZnSO4, at a concentration of 0.001 mM, significantly attenuated the increased levels of cytoplasmic mono- and oligonucleosomes evoked by 0.001 mM NH2Cl. Polaprezinc and L-carnosine, but not ZnSO4, also inhibited NH2Cl-induced β-carotene bleaching in the cell-free system. In conclusion, polaprezinc, especially its subportion L-carnosine, inhibited NH2Cl-evoked gastric epithelial DNA fragmentation, suggesting a role for this agent in preventing the progression of gastric epithelial injury induced by NH2Cl.
|Number of pages||4|
|Journal||Journal of Gastroenterology|
|Issue number||SUPPL. 11|
|Publication status||Published - 12-1999|
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