Abstract
Purpose: :
To observe cell responses after PDGF-BB stimulation in corneal and scleral stromal cells and to investigate inflammatory reactions in cornea or sclera.
Methods: :
The cell strains derived from human corneal or scleral stromal cells and the primary culture cells of corneal and scleral stromal cells were used. The cell strains were established by transfection of E6E7 gene in human papilloma virus 16 bector. The changes of gene expression patterns after PDGF-BB stimulation (10 ng/ml, 24 hours) were analyzed with the DNA microarray in the scleral stromal cells. The up-regulation of the gene expression was confirmed in the corneal and the scleral stromal cells by RT-PCR and Western blotting. Expression of the bioactive factors was observed immunohistochemically in the human specimens from 9 cases, including endophthalmitis or malignant melanoma.
Results: :
DNA array analysis revealed that thrombomodulin (TM) gene was included in the genes induced in the scleral stromal cell strains after the stimulation of PDGF-BB. The expression of TM at mRNA level was confirmed to increase in both the corneal and the scleral stromal cells by RT-PCR. The expression of TM at protein level was increased only in the scleral stromal cells, but not in the corneal cells. TM protein was localized in the membrane compartment more than in the cytoplasmic compartment. IL-18 was increased at mRNA level in the scleral stromal cells after the stimulation by TM. PDGF-BB, TM, and IL-18 were detected in the area with inflammatory reaction in the scleral and the corneal stromal cells immunohistochemically.
Conclusions: :
PDGF-BB induced TM expression in the scleral stromal cells and the corneal cells. Furthermore TM induced IL-18. This cascade of biologically active factors may be involved in the regulation of inflammation of sclera and cornea. The present results showed that the scleral stromal cells play different roles from the corneal stromal cells.
Keywords: sclera • cornea: stroma and keratocytes • cornea: basic science