Western blot analyses of the NOD1 and NOD2 proteins (A and C). The rats were administered vehicle (0) or were infected with S. pneumoniae (1 × 106 bacteria) via intracisternal injection. At days 1 (D1), D2, and D3 postinfection, protein isolates were assayed for the presence of NOD1 (Panel A) and NOD2 (Panel C). NOD1 and NOD2 protein levels were quantified by densitometric analyses and normalized to β-actin expression (Panels B and D). The asterisks indicate statistically significant differences compared to the corresponding uninfected animals (p < 0.05).