Figure 6. Cx37 expression at venous valves is maintained after a prolonged disruption of blood flow.
(A) Cx37 immunostaining of a vein valve section from a WT saphenous vein ligated for 24 hrs shows that Cx37 expression persists at the valve (arrow) after a prolonged disruption of venous blood flow, although the Cx37 staining appears somewhat disorganized. (B) Cx37 expression at the valve (arrow) is still detected in a saphenous vein ligated for 72 hrs. (C) Phase contrast image of the vein shown in B. (D) At 24 hr post-ligation, Cx43 but not Cx37 expression is strongly induced in the non-valve endothelium (arrowheads) of the ligated saphenous vein, where there is normally no Cx43 expression. (E) At 8 hr post-ligation, Cx43 expression is already induced in the non-valve endothelium of the saphenous vein. The image shows a high magnification view of Cx43 staining in a glancing section of the non-valve endothelium. (F) The same section as in E immunostained for Cx37, shows that Cx37 is not induced by the 8 hr ligation. (G,H) Adjacent sections of a ligated saphenous vein immunostained for Cx37 (G) and Foxc2 (H), shows that Foxc2 expression is maintained at the valve (arrows) along with Cx37 when flow is disrupted. Blood flow would normally be from left to right in these specimens. Scale bars: (A) 50 µm; (B and C) 50 µm; (D) 50 µm; (E and F) 10 µm; (G and H) 10 µm.