Figure 5: Effect of GRK2 inhibition on oxidative stress. (a) The expression of gp91phox mRNA was measured by real-time quantitative polymerase chain reaction (PCR). The data were presented as the fold change relative to the non-diabetic controls. (b) gp91phox protein expression was measured by western blot analysis. β-actin was used as a loading control. (c) Expression levels of gp91phox protein were normalized to β-actin. (d) ROS production in cavernosal tissue was expressed as CPM mg-1 protein. Results were reported as mean ± standard deviation (s.d.). *P < 0.05, the indicated group versus control group; ‘P < 0.05, the indicated group versus T2DM+vehicle group; n = 20 per group. All results are representative of three independent experiments. CPM: counts per min; GRK2: G protein-coupled receptor kinase 2; T2DM: type 2 diabetes mellitus; ROS: reactive oxygen species.