(A) ELISA of TNF-α showing significant decreases in various TNF-α shRNA vectors. Statistical significance was determined by Mann-Whitney test (*P < 0.05 vs. untreated; #P < 0.05 vs. TNF-α alone, n = 5). (B) Akt phosphorylation activity increased significantly after treatment with shRNA alone, shRNA+salmeterol, and salmeterol-alone samples. (C) Western blot analysis of phosphorylation of IRS-1Ser307 showed a significant decrease in shRNA alone and shRNA+salmeterol-treated cells compared with the high-glucose samples. Treatment with salmeterol also significantly decreased the phosphorylation of IRS-1Ser307 in Müller cells. Significance was determined by one-tailed, nonparametric Mann-Whitney tests on Western blot data (*P < 0.05 vs. 25 mM glucose, $P < 0.05 vs. salmeterol n = 4, #P < 0.05 vs. 5 mM Glucose, n = 4).