Fig. 1

Significant increase in bacterial translocation into the CNS of mice chronically treated with morphine and HIV-1 Tat and co-infected with S. pneumoniae at the 5th day of post-pellet implantation. a Real-time in vivo bioluminescence imaging of luciferase-tagged S. pneumoniae (serotype 3) administered (i.p.) in live wild-type (wt) and μ-opioid receptor knockout (MORKO) mice chronically treated with morphine and HIV-1 Tat. b Histograms of mean bioluminescent signals from luciferase-tagged S. pneumoniae quantified as total photon emission from treated live mice. c, d Bacterial translocation into the CNS was detected in perfused mice brain using Xenogen’s IVIS CCD camera system, and total photon emission was quantified using Igor image analysis software. e Luciferase activity was measured in the whole brain tissue dissected out from treated mice. Brain lysates were isolated by homogenizing the brain tissue, and luciferase activity was measured using a luminometer, TD-20/20. Relative luminescence units (RLU) were normalized with the Renilla luciferase values. f Histograms of mean bacterial counts in brain tissue. Error bars indicate the standard error of the mean (SEM) of six different animals from each group (n = 6). Pseudocolor scales are shown to right of the figures. PP placebo pellet, MP morphine pellet. *P < 0.05; **P < 0.01