Figure 5. Electron microscopy (EM) analysis of capillary basement membrane (BM) thickening in rat retinas. A-D: Effect of fibronectin (FN)-siRNA on retinal capillary BM thickening in diabetic rats. Representative EM images of transverse sections of retinal capillaries of (A) normal rat, (B) diabetic rat, (C) diabetic rat intravitreally injected with FN-siRNA, and (D) diabetic rat intravitreally injected with scrambled siRNA; scale bar=1 μm. Enlarged views: E-H; scale bar=100 nm. FN-siRNA treatment in the diabetic rats specifically prevented BM thickening (arrowheads) compared to uninjected diabetic rats. (I) Graphical representation of retinal vascular BM thickness in four groups of rats: normal, diabetic, diabetic injected with FN-siRNA, and diabetic injected with scrambled siRNA, showing that an intravitreal injection of FN-siRNA reduces retinal capillary BM thickening in diabetic rats. Normal versus Diabetic *=p<0.05; Diabetic versus Diabetic+FN-siRNA **=p<0.05, n=8.