Abstract
Purpose: :
This study was conducted to investigate the therapeutic effect of alkaline serine protease (ALP) and phospholipase B (PLB) gene silencing on a mouse model of experimental keratitis challenged with Aspergillus fumigatus.
Methods: :
Specific vectors of plasmid pBC-hygro containing a dsRNA coding sequence and a GFP sequence were constructed for RNA interference (pALP and pPLB). Mice were injected subconjunctivally with 10 µg pALP ,pPLB either or both as treatment after challenge with Aspergillus fumigatus. The severity of keratomycosis in the animals was scored visually with the aid of a dissecting microscope and slit lamp. Eyes were enucleated and homogenized at 6h, 1, 3, and 7 days after subconjunctival injection to evaluate the ratio of MMP-9/TIMP-1 and MMP-2/TIMP-2 by western blot.
Results: :
The inhibition of RNA interference on ALP and PLB gene expression in the transformant were 65.35% and 40.94%. The scores of the eyes treated with pALP or pPLB, especially with pALP and pPLB, were significantly lower than the controls from 1 day to 7 days after fungal after subconjunctival injection (p<0.01). Administration of pALP and/or pPLB resulted in a significant downregulation of MMP-9/TIMP-1 (p<0.01) and a slightly but insignificant upregulation of MMP-2/TIMP-2 (p>0.05). The reduction of MMP-9 in the treated eyes were much greater than the control (p<0.01).
Conclusions: :
The results imply that ALP and PLB have important roles in corneal destruction during fungal keratitis by regulating the expression of MMP-9/TIMP-1 and MMP-2/TIMP-2 in cornea, and suggests that RNA interference with specific vectors targeting ALP and PLB of the pathogenic Aspergillus fumigatus may become a novel therapeutic strategy for fungal keratitis.
Keywords: cornea: basic science • inflammation