Purpose: To explore the variability in interleukin-12 (IL-12) secretion in human corneal fibroblasts (HCFs), the effects of IL-12 on HCF viability and migration, and the effects of recombinant human transforming growth factor-β1 (rhTGF-β1) and moxifloxacin (MOX) on IL-12 expression.
Methods: IL-12 secretion in 27 primary HCFs incubated with rhTGF-β1 and/or MOX was analyzed using immunoblotting. Viability and migration were assessed using WST-1 assay and culture inserts, respectively. The effects of IL-12 on HCFs were verified via adding recombinant human IL-12 (rhIL-12) or silencing IL-12. The effects of rhTGF-β1 and MOX on IL-12 secretion were also verified.
Results: There were 25.9% HCFs that did not secrete IL-12 and 74.1% HCFs that secreted IL-12 were divided into low- (25.9%), medium- (37.0%), and high-secretion (11.1%) subgroups. After 3-day incubation, rhTGF-β1 stimulated IL-12 by 1.90 ± 0.84 folds (P = 0.026), with no difference in folds of induction among subgroups (P = 0.870). MOX suppressed IL-12 secretion concentration-dependently, more noticeably in the presence of rhTGF-β1. Exogenous rhIL-12 enhanced HCF proliferation (1.29 folds, P < 0.001) and migration. In contrast, rhTGF-β1 only enhanced proliferation (1.24 folds, P < 0.001). In IL-12-silenced HCFs, rhTGF-β1 failed to enhance IL-12 secretion and resulted in reduced cell proliferation and migration.
Conclusions: IL-12 enhanced HCF proliferation and migration. TGF-β1 per se enhanced HCF proliferation but not migration. However, it promoted migration indirectly through upregulating IL-12 secretion. MOX-inhibited HCF migration via suppressing IL-12 secretion. The interindividual variation in IL-12 secretion might contribute to disparity in HCF proliferation and migration after corneal wounding among individuals.