Lornoxicam suppresses recurrent herpetic stromal keratitis through down-regulation of nuclear factor-κB: an experimental study in mice

PURPOSE We designed the current study to determine the protective effects of lornoxicam, a cyclooxygenase (COX) inhibitor, on recurrent herpetic stromal keratitis (HSK) and the nuclear factor-kappaB (NF-kappaB)-mediated mechanism in mice. METHODS A corneal latent herpes simplex virus-1 (HSV-1) infected mouse model was established. Six weeks later, Ultraviolet B (UVB) irradiation induced the recurrence. Corneal swabs were obtained and cultured with indicator cells to determine shedding of the virus. Lornoxicam was administered intraperitoneally daily, beginning one day before irradiation and lasting for seven days. Saline-treated and mock-infected control groups were also studied at the same time. Development of corneal inflammation and opacity was scored. Immunohistochemical staining and an electrophoretic mobility shift assay were performed to evaluate the effect of lornoxicam on NF-kappaB activation in the corneal tissues. The levels of tumor necrosis factor-alpha (TNF-alpha) in the cornea were determined by an enzyme-linked immunosorbent assay (ELISA). RESULTS HSV-1 reactivation induced stromal edema and opacification concomitantly with elevated activation of NF-kappaB and elevated production of TNF-alpha. Lornoxicam treatment significantly decreased the incidence of recurrent HSK, attenuated the corneal opacity scores, and also effectively suppressed both NF-kappaB activation and TNF-alpha expression in biological analysis. Histopathology examination revealed a reduced immunostaining positive cell density for NF-kappaB in the cornea from lornoxicam-treated mice as well as a diminished inflammatory response. CONCLUSIONS Lornoxicam exerts protective effects against HSK, presumably through the down-regulation of NF-kappaB activation.