Abstract
Abstract: :
Purpose:SPARC (secreted protein which is acidic and rich in cysteine) is thought to modulate the interaction between the cells and the extracellular matrix. We previously reported that SPARC-derived peptide inhibited the collagen gel contraction by keratocytes. In this study, to understand the action of SPARC on the corneal stromal wound healing, we investigated the effects of SPARC-derived peptide (peptide 4.2a), corresponding to domain IV of SPARC, on the interaction between keratocytes and collagen matrix. Methods:We synthesized peptide 4.2a (amino acid 254-270 at domain IV). Rabbit keratocytes were seeded on the coverslips, which were previously coated by collagen type I. Peptide 4.2a was added to the medium and the cultivation was curried out at 37 ºC. At 10, 30 and 60 minutes after seeding, the cells were fixated by 4% paraformaldehyde and were observed under a scanning electron microscope (SEM). In other examination, the cells were stained with eosin and the cell surface area on the collagen matrix was measured using a digital graphic analyzer (Nicon E800). Results:Under a SEM, keratocytes were observed to be spreading on the collagen matrix in proportion to the culture periods. When keratocytes were cultured with peptide 4.2a, the cells on the collagen matrix did not spread and showed to be round throughout the incubation period. In unsupplemented control group, cell area increased time dependently. However, the area of keratocytes cultured with peptide 4.2a did not change at any incubation periods. Conclusion:These findings showed that peptide 4.2a inhibited the spreading of keratocytes on the collagen matrix. It was also suggested that peptide 4.2a will be a modulator of the corneal stromal wound healing.
Keywords: 374 cornea: stroma and keratocytes • 403 extracellular matrix • 339 cell adhesions/cell junctions