Figure 5.

ET-1 increased arteriolar constriction and reduced functional capillary density in PbN-infected mice. Brain intravital microscopy was performed to assess vessel patency and functional capillary density. A: At 5 days postinfection (dpi), both PbA-infected mice and PbN-infected mice treated with ET-1 displayed significantly narrower vessels than their preinfection baseline, whereas all other treatment groups had no change in their vessel diameter. B: At 6 dpi, all infected mouse groups, and ET-1–treated uninfected mice had a significant decrease in their vessel diameter from baseline. In PbA-infected mice and in PbN-infected mice treated with ET-1, this decrease was significantly more pronounced. ET-1 treatment induced a significantly greater vessel narrowing than PbN-infected mice given normal saline or uninfected mice treated with ET-1. C and D: All infected mice and uninfected mice treated with ET-1 had significantly lower functional capillary density than uninfected control mice given saline, at 5 and 6 dpi; however, PbA infection resulted in significantly more pronounced reduction in functional capillary density than PbN infection on both days. D: At 6 dpi, ET-1 treatment significantly reduced the number of functional capillaries in PbN-infected mice. ^∗P < 0.05, ^∗∗P < 0.01, and ^∗∗∗P < 0.001 when comparing groups; ^†P < 0.05, ^††P < 0.01, and ^†††P < 0.001 relative to baseline measurements.