Excess protein aggregation in the frontal brain of ZDF (zucker diabetic fatty rat) compared to Lean. (A) ZDF brain shows doubling of the expression of protein aggregates (tangles). (B) Higher protein synthesis levels in ZDF brains indicated by higher protein/DNA ratio. (C) ZDF brain shows increased number of neurofibrillary tangles. Silver staining depicts tangles in dark brown/black elements with a diameter of 10–20 μm as magnified in top inset. (D) ZDF displays increased levels of tau proteins as found by Western blotting. (E) Real-time PCR analysis of the mRNA expression of total tau relative to β-actin. (F) ZDF displays increased levels of tau protein isomers and tau protein cleavage as found by immunohistochemistry (indicated by →). (G) ZDF displays increased levels of fibronectin as found by Western blotting. (H) Real-time PCR analysis of the mRNA expression of fibronectin relative to β-actin. (I) Immunohistochemistry analysis shows higher fibronectin expression in ZDF rats in comparison with Lean (indicated by →). Magnification 40×, Data are Means ± SEM (n ≥ 5 per group), * <0.0001 (difference to control gray bars in each group); unpaired t-test. Western blot expression is normalized to β-actin; lanes of western blot insets are in the same order as in the X-axis.