Figure 4. siRNA's are effective in reducing inflammatory responses in a murine model of EHV-1 infection when applied 0.5 h before infection.
(A). Development of mean body weights after infection. Balb/c mice (groups of 12) were transfected intranasally with sigB3 and siOri2, alone or in combination, and mice were infected intranasally with 1×105 PFU of Ab4 0.5 h later. Mice inoculated with 75 pmol siLuc were used as positive controls and uninfected negative control mice were also included. Mean body weights were determined on the day of infection (day 0) up to day 14 p.i. Mean body weights on the day of infection were set to 100%. Standard deviations (SD's) ranged from 0.7 to 2.8%. The day of the maximal SD's for each group are indicated in brackets. The days where statistical significant differences (SS) were observed, as determined with non-parametric Wicoxon-Whitney and Kruskal Wallis analyses, are also given between brackets. Histopathology. A total lung score was determined at day 2 p.i. in three mice of each group and graded on a scale of 0+ (normal) to 5+ (severe), as described in Materials and Methods. Asterisks indicate statistically significant differences (p<0.05) (B). Representative H&E images showing histological features in lungs of mice treated with the control siLuc and mice treated with siRNA's against EHV-1 genes. BH: bronchiolar hyperplasia, II: interstitial inflammation, BN: bronchiolar necrosis (C).