Cx43 expression is decreased in diabetic kidneys and high glucose-induced GMCs. (A, B) Phosphorylation of Cx43 and total Cx43 expression in kidneys of db/db mice and STZ-induced diabetic rats were detected by immunoblotting. (C) Cx43 expression was measured by immunohistochemistry in kidneys of STZ-induced rats. Staining without the Cx43 antibody was used as a negative control. (D) Images of frozen kidney sections from STZ-induced diabetic rats stained doubly with anti-Cx43 antibody and anti-Thy-1.1 antibody (a) or anti-RECA-1 antibody (b). Red fluorescence indicates Cx43. Green fluorescence indicates thy-1.1 (a) or RECA-1 (b). Blue fluorescence indicates nuclei. Scale bar represents 10 μm (magnification 400×). (E) GMCs were cultured in DMEM containing normal glucose (NG; 5.5 mmol/L) and serum starved for 16 h before exposure to high glucose (HG; 30 mmol/L). Cx43 expression was measured by immunofluorescence after 30 min of HG stimulation (upper panel). Phase contrast views are also shown (second panel). Green fluorescence indicates Cx43. Scale bar represents 100 μm (magnification 100×). Scale bar represents 20 μm in magnification views (lower panel, magnification 400×). (F) Cx43 was measured by immunoblotting after treatment for 30 min with high glucose (30 mmol/L). Mannitol (30 mmol/L) was used as an osmotic control. Experiments were performed at least three times with similar results. *P<0.05 vs. control group.