Abstract
Abstract: :
Purpose: Herpes stromal keratitis (HSK) results from the infection of herpes simplex virus (HSV) in cornea. HSV infection, mainly recurrent, is a leading cause of corneal scarring and visual loss. No specific HSV viral proteins or peptides are identified from HSK corneas. Thus, the mechanisms involved in the development of HSK are still an enigma. A novel approach was taken to identify a potential viral protein associated with the development of HSK. Methods: Rabbits were bilaterally infected with 2X105 PFU of HSV1 McKrae into the eyes. Tear films were collected for acute ocular replication. Latency is assumed to have been established by 28 days postinfection (pi). Recurrent ocular disease was monitored from days 30 to 58 pi. Briefly, corneal scarring was scored as being present or absent and was visualized by the unaided eye, photographed, and confirmed by slit lamp biomicroscopy at the time of sacrifice. Corneas from acute and latent rabbits were trephined and immediately immersed in cold PBS buffer with cocktail protease inhibitors. The sample was kept on ice for two hours and the supernatant following centrifugation to clear debris was subjected to SDS–PAGE, transferred onto membrane and Western blot was performed using several well–characterized HSV1 monoclonal antibodies. Results: The following results were observed in rabbits infected with HSV–1; 1) ICP0 was the only viral protein consistently detected in water–soluble corneal extract from HSV induced stromal keratitis corneal buttons. 2) Interestingly, the presence of ICP0 in keratitis corneal button was coincident with the loss of the abundant water soluble corneal protein, Aldehyde dehydrogenase 1 (ALDH1), a suggestive–structural protein contributing to the transparency of the cornea. 3) The progressive physical appearances of eye infection were correlated to the loss of ALDH1 and the detection of ICP0 in the corneal buttons during acute infection. When the acute eye disease resolved in two weeks; ICP0 was no longer detectable which was coincident with the detection of ALDH1 in corneal buttons, and the global appearance of infected eyes resumed to normal. Conclusions: Our findings provide the first viral molecular marker associated with the pathogenesis of the development of HSK, and possibly shed a new light on new drug development and treatment of HSK.
Keywords: herpes simplex virus • immunohistochemistry • keratitis