Fig. 1
HSV-1 replication in thalamus and hindbrain leads to increased mortality on day 6 p.i. 6-week-old C57BL/6N male mice (n = 12 mice) were intranasally infected with 6 × 105 PFUs of HSV-1 strain H25 in 20 μl MEM. a Survival curves of HSV-1-infected vs. uninfected control mice. Survival rates were analyzed using a log-rank (Mantel–Cox) test. b Viral titers in homogenates of brains were measured by a standard plaque assay on Vero cells on days 0, 4 and 6 p.i.. The results are reported as PFUs per milligram (mg) of brain homogenates and represent the means ± SEM for 4 mice per group at each timepoint. c Representative bioluminescence image of mouse infected with 6 × 105 PFUs of recombinant HSV-1 (rHSV-1) on the left and uninfected control mouse on the right side, on day 6 p.i. The bioluminescent signal is expressed in average radiance (p/s/cm2/sr). d Identification of HSV-1+ brain regions on day 6 p.i. Viral titers in homogenates of different brain regions were measured by a standard plaque assay on Vero cells. Representative sagittal (e) and coronal (f) brain sections illustrating the localization of HSV-1 proteins (red) on day 6 p.i. Brain sections were immunostained with a primary polyclonal rabbit anti-HSV-1/2 antibody and a secondary Alexa-594 conjugated anti-rabbit antibody, followed by staining with DAPI (blue) (scale bar = 1 mm). HSV-1 signal was localized in the ventral posterolateral nucleus (VPL) of the thalamus (white squares) and hindbrain (cerebellum, medulla, and pons). Brain regions are indicated on the representative sagittal and coronal mouse brain sections inserted in the left corners (AON.: Anterior olfactory nucleus, C.: Cerebellum, HC.: Hippocampus, HT.: Hypothalamus, IC.: Isocortex, M: Medulla, MB.: Midbrain, OB.: Olfactory bulb, P.: Pons, S: Septum, T.: Thalamus, VPN: Ventral posterior nucleus, VS.: Ventral striatum). f All statistical analyses were performed using Kruskal–Wallis with “Dunn’s multiple comparisons test.” Statistically significant results are indicated as follows: *P < 0.05; **P < 0.01