IL-6 localized to endothelial cells of coronary arterioles.

<p>Dual fluorescence combining IL-6 with markers for endothelial cells [von Willebrand factor (vWF)], vascular smooth muscle cells (α-actin) and macrophages (CD68). (A, B, and C) Dual labeling of IL-6 (red) and vWF (green) in control mouse heart tissues. (D, E, and F) Dual labeling of IL-6 (red) and vWF (green) in db/db mouse heart tissues. Arrows in C and F show the colocalization of IL-6 and endothelial cells (yellow) in the control and db/db mice. (G, H, and I) Dual labeling of IL-6 (red) and α-actin (green) in control mouse heart tissues. (K, L, and M) Dual labeling of IL-6 (red) and α-actin (green) in heart tissues of db/db. Arrows in I and M show the α-actin staining with absence of IL-6 staining in the control and db/db mice. Inserts in I (J) and in M (N) show the higher magnification indicated by arrows in I and M. O, P, and Q, dual labeling of IL-6 (red) and marker of macrophage (green) in db/db mouse heart tissues. Arrows in Q show the specific CD68 staining with absence of IL-6 staining. (R and S) Negative control: arrows show the absence of staining in vessels with control IgG and without primary antibodies. (T) Staining of nuclei with DAPI (blue) in heart tissues of the db/db mice. The immunostaining results suggest that in the hearts of type 2 diabetic mice, IL-6 is mainly localized in endothelial cells, but not in vascular smooth muscle cells and macrophages. Magnification×40. Data shown are representative of 4 separate experiments.