FIG. 1.

Effects of Rac1 knockout on NADPH oxidase and ROS production. Rac1-ko mice (KO) and their WT littermates were injected with STZ. Two months later, NADPH oxidase activation and expression and ROS production in heart tissues were measured. A: Translocalization of Rac1 and p67^phox to the membrane. The protein levels of Rac1 (mRac1) and p67^phox (mp67^phox) were decreased in the membrane fractions of Rac1 KO compared with WT diabetic hearts. The top panel is the representative Western blot for membrane mRac1, mp67^phox, and gp91^phox from three out of five to six different hearts in each group, and the lower panel is the quantification of mRac1, mp67^phox, and gp91^phox. NADPH oxidase activity (B), superoxide production (C), and H₂O₂ production (D) were decreased in diabetic Rac1 KO compared with WT hearts. C is the representative DHE staining (Red signal) for superoxide production from five to six different hearts in each group. E: Rac1, p67^phox, and gp91^pho protein expression. The protein levels of Rac1 and p67^pho were decreased in Rac1 KO compared with WT diabetic hearts. The top panel is the representative Western blot for Rac1, p67^phox, and gp91^phox from three out of five to six different hearts in each group and the lower panel is the quantification of Rac1, p67^phox, and gp91^phox. F: Mitochondrial superoxide production was increased in WT diabetic hearts, which was significantly decreased in Rac1 KO hearts. G: Thioredoxin reductase activity was preserved in Rac1 knockout diabetic hearts. Magnification ×40. Data are means ± SD, n = 5–8. *P < 0.05 vs. sham; #P < 0.05 vs. STZ in WT. (A high-quality digital representation of this figure is available in the online issue.)