FIGURE 4.

Cyclooxygenase-2 inhibition induces a decrease of bacterial burden in draining lymph nodes. C57BL/6 mice (n = 5) were infected with B. melitensis (10⁴ bacteria per mice) intradermally into ear pinnae. After infection mice received 15 mg/kg of COX-2 inhibitor (NS-398) or DMSO (mock-treated mice) intraperitoneally daily for 7 days. Data represent two independent experiments. (A) At 8 days post-infection mice were sacrificed and organs were harvested and CLN (Left panel) and spleen (Right panel) were weighted. Statistical significance was determined using ANOVA (^∗p < 0.05; ^∗∗∗∗p < 0.0001). (B) At 8 days post-infection mice were sacrificed and organs were harvested and analyzed for their CLN (Left panel) or spleen (Right panel) bacterial loads by plating homogenates on nutrient agar. Statistical significance was determined using unpaired, two-tailed Student’s t-test (^∗∗p < 0.005). (C) At 8 days post-infection, total RNA of the CLN was extracted and analyzed for expression of genes involved in inflammatory response by reverse transcription real-time PCR. Results are given as fold increase compared to the signal obtained for mock-infected mice. Statistical significance was determined using unpaired, two-tailed Student’s t-test (^∗∗p < 0.005; ^∗∗∗p < 0.001; ^∗∗∗∗p < 0.0001).