Fig. 6.
The expression of MMP-9 is augmented earlier in Reynolds-infected mice. Mice infected with either S. aureus strain RN6390- or S. aureus strain Reynolds- encapsulated agarose beads (104CFU) as well as sterile beads as described in Materials and methods, whereupon brain abscess homogenates were prepared (n=4 to 6 animals per group for each time point) at the indicated intervals and analyzed for MMP-9 mRNA and protein expression by qRT-PCR (A) and Western blotting (B), respectively. (A) MMP-9 gene expression was normalized to the house keeping gene GAPDH expression for each tissue and then normalized to that of naïve brain mRNA. The results represent the mean (±SEM) of three independent experiments. Significant differences between S. aureus strain RN6390- and Reynolds-infected mice are denoted with asterisks (*, p<0.05), while the pound sign represents the difference in the same group from other time points (#, p<0.05). (B) Western blots were stripped and reprobed with an antibody specific for actin to verify the uniformity in gel loading. Results are presented from two or three individual mice per group for each time point and representative of three independent experiments.