Interleukin-6 in tear fluid after photorefractive keratectomy and its effects on keratocytes in culture.

PURPOSE: To investigate the participation of interleukin-6 (IL-6) after photorefractive keratectomy (PRK) and its possible roles and sources in corneal wound healing. METHODS: IL-6, levels were measured in the tear fluids of patients before and after PRK and in conditioned media of human corneal epithelial cells and keratocytes. Its effects on total collagen and collagen-type synthesis by keratocytes were studied with a 3H-proline incorporation assay and Northern blot analysis. Zymography was used to evaluate the metalloproteinase content in the conditioned medium of IL-6-stimulated keratocytes. RESULTS: IL-6 is present in the tear fluid samples after photorefractive keratectomy, possibly synthesized by epithelial cells and keratocytes. CONCLUSIONS: IL-6 stimulates collagen synthesis in general and collagen type I in particular. Furthermore, it reduces the production of MMP-2, the latent form of the metalloproteinase, by cultured keratocytes. The results suggest that IL-6 might be regarded as a mediator involved in corneal healing after excimer laser.

[Leber's optic neuropathy: new diagnostic prospects]. / Neuropathie optique de Leber: nouvelles perspectives diagnostiques.

The diagnosis of Leber's hereditary optic neuropathy, essentially based on a family history of a similar illness, becomes difficult in sporadic cases. In this disease, mitochondrial DNA mutations have been recently discovered and detected by digestion with restriction enzyme after amplification by the Polymerase Chain Reaction. We present two patients in whom these molecular biological techniques confirmed the diagnosis of Leber's hereditary optic neuropathy in the absence of a convincing family history. These new molecular biological methods, providing a precious diagnostic test, would certainly play a greater part in genetic counselling and would probably be a prerequisite for the development of new forms of therapy.