Although the detailed mechanism is unclear, zinc and its derivative, polaprezinc, have been reported to accelerate gastric ulcer healing in vivo.Aim:
To investigate the detailed cellular mechanism of polaprezinc on gastric epithelial cells and fibroblasts with special attention to insulin-like growth factor I (IGF-I).Methods:
Isolated rabbit gastric epithelial cells formed a complete monolayer, from which a circular artificial wound with constant size was made. The restoration process was monitored by measuring wound size up to 48 h. Either polaprezinc, IGF-I, fibroblast conditioned medium or neutralized medium conditioned by anti-IGF-I antibody was added at the time of wounding. The expression of mRNA of IGF-I, hepatocyte growth factor (HGF) and transforming growth factor α (TGF-α) in fibroblasts with or without polaprezinc treatment was tested using reverse transcription polymerase chain reaction (RT-PCR). Gastric epithelial cell proliferation was also examined by bromodeoxyuridine (BrdU) staining.Results:
IGF-I and fibroblast conditioned medium treatment accelerated gastric epithelial restoration which included cell migration and proliferation. However, polaprezinc and neutralized conditioned medium treatment did not accelerate epithelial repair. RT-PCR for growth factor mRNA revealed the IGF-I mRNA expression in fibroblasts was increased after treatment with polaprezinc.Conclusion:
Polaprezinc induced IGF-I production from mesenchymal cells, resulting in stimulation of epithelial cell restoration through a paracrine pathway. IGF-I may play an important role in gastric wound repair.