Abstract
Purpose: :
To investigate the consequences of interaction between corneal fibroblasts and infiltrated neutrophils during ocular inflammation, we measured the release of inflammatory cytokines from human corneal fibroblasts (CFs) and polymorphonuclear leukocytes (PMNs) cultured alone or together.
Methods: :
CFs were prepared from human tissue left over from corneal transplantation surgery. PMNs were isolated from venous blood of healthy volunteers. CFs and PMNs were cultured for 20 hours alone or together at a density of 2 × 105 and 1 × 106 cells/mL, respectively, in RPMI 1640 medium supplemented with 5% human AB–type serum. The concentrations of interleukin (IL)–6, IL–8, and granulocyte colony–stimulating factor (G–CSF) in the culture supernatants were then determined by suspension array system.
Results: :
IL–6 was present at a concentration of 0.9 ± 0.0 ng/mL in culture supernatants of CFs but was not detected in those of PMNs; it was present at 11.6 ± 2.0 ng/mL in the supernatants of cocultures. The concentration of IL–8 was 40.5 ± 26.0, 0.8 ± 0.1, and 133.0 ± 49.9 ng/mL in culture supernatants of CFs, PMNs, and cocultures, respectively. Neither CFs nor PMNs released G–CSF when cultured separately, but the concentration of this cytokine in the supernatants of cocultures was 0.9 ± 0.1 ng/mL.
Conclusions: :
CFs cultured alone released both IL–6, which induces inflammatory responses, and IL–8, which induces chemotaxis of PMNs. PMNs cultured alone released IL–8. The amounts of IL–6 and IL–8 released by these cells, however, were greatly increased by coculture. Neither CFs nor PMNs alone released G–CSF, which regulates the proliferation and differentiation of PMNs, but coculture of the two cell types resulted in the secretion of substantial amounts of this cytokine. The interaction of corneal fibroblasts with polymorphonuclear leukocytes during ocular inflammation may markedly potentiate the secretion of inflammatory cytokines.
Keywords: cornea: stroma and keratocytes • cytokines/chemokines • inflammation