Purpose: To investigate cytokine mRNA expression and the influence of acyclovir and tetrandrine on that expression in the corneas of mice infected with herpes simplex virus type 1 (HSV-1).
Methods: Male BALB/c mice were infected in the right cornea with HSV-1. The corneas were harvested from control normal mice and from untreated, acyclovir-treated and tetrandrine-treated mice 14 days after infection. The infected corneas of each group were divided into inflamed and uninflamed depending on clinical observation. After total mRNA extraction from the corneas, gene expression of interleukin 1 beta (IL-1 beta), IL-6, tumour necrosis factor alpha (TNF-alpha) and transforming growth factor (beta (TGF-beta) was analysed by reverse transcription polymerase chain reaction.
Results: No mRNA expression of the cytokines was found in normal corneas. IL-1 beta and TNF-alpha mRNA was seen in inflamed corneas, while mRNA expression of IL-6 and relatively weaker TGF-beta mRNA expression were found both in inflamed corneas and in infected but uninflamed corneas treated with acyclovir. TNF-alpha mRNA was present in the uninflamed corneas of tetrandrine-treated mice. No influence of either agent was found on TGF-beta gene expression.
Conclusions: The results suggest that local IL-1 beta and TNF-alpha gene expression is required for corneal inflammation, whereas IL-6 and TGF-beta may exert antiviral and inflammation regulatory activities in HSV corneal infection.