Figure 5

Protective effect of dexamethasone on apoptosis induced by B . burgdorferi in primary rhesus DRG cultures. (A-C) show representative images of sensory neurons in DRG cultures (red) staining with the neuronal marker NeuN, exposed to medium (A), live B. burgdorferi at a MOI of 10:1 (B) and B. burgdorferi plus dexamethasone 15 μM (C), respectively after 24 hours of incubation. Apoptotic nuclei are visualized in green as detected by the in situ TUNEL assay. The nuclei of all cells appear blue due to staining with the nuclear stain TOPRO3. (D) shows percent apoptosis as measured by the in situ TUNEL assay and quantified by confocal microscopy after 24 hours of incubation of DRG cultures exposed to medium or B. burgdorferi at a MOI of 10:1 in the presence and absence of dexamethasone (* P <0.05). Data represent percent apoptosis mean values from DRG cells that were isolated from two adult rhesus macaques. Values for each animal were determined in duplicate. Error bars represent standard deviations. DRG, dorsal root ganglia; MOI, multiplicity of infection; TUNEL, terminal deoxynucleotidyl transferase mediated UTP nick end labeling.