Effects of TNF and IL-1β on pericyte shape change in vivo. (A) WT mice were injected with either TNF or IL-1β for 2 or 4 h, respectively, into the cremaster muscle or intradermally in the ear. Tissues were then dissected away, fixed, and immunostained for the pericyte marker αSMA before being analyzed by confocal microscopy. Bars, 10 µm. (B) The graphs show the mean gap size between adjacent pericytes in unstimulated, TNF-, and IL-1β–stimulated venules of cremaster muscles (left) or the skin of the ear (right). Statistical significance between cytokine-stimulated tissues from the control group is indicated by asterisks. *, P < 0.05; ***, P < 0.001. Images are representative of n = 9 experiments (A) and results are expressed as mean of n = 7 mice per group (B; one mouse/experiment).