1
Ld lower than the cumulative doses needed to produce cancer in experimental animals [93-96], and beginning in early adolescence, we pair-fed the rats with either high (60 ) or low (5 ) fat containing diets. The NDEA doses were selected to be far below those needed for carcinogenesis and were based on empirical studies demonstrating absence of acute toxic effects in the rats.Longer durations of NDE
1
S described elsewhere [79]. For molecular and biochemical assays, cerebella were snap-frozen in a dry ice-methanol bath and stored at -80 . We studied cerebellar tissue because the cerebellum: 1) requires intact insulin/IGF signaling to maintain its structural and functional integrity [80,81]; 2) is severely damaged by i.c.-STZ mediated neurodegeneration [19,22]; 3) although relatively spared, it
1
S such as diabetes mellitus [74], chronicTong et al. BMC Endocrine Disorders 2010, 10:4 http://www.biomedcentral.com/1472-6823/10/Page 3 ofalcoholism [75], or obesity with metabolic syndrome [45,46]. These systemic diseases share in common with primary central nervous system (CNS) degenerative diseases, impairments in cognition, and deficits in insulin and IGF signaling mechanisms, insulin/IGF res
1
S performed using the ABC method, and revealed with DAB (brown precipitate)-see Experimental Procedures. Sections were lightly counterstained with Hematoxylin (blue) to help reveal the tissue architecture. Cerebellar layers: ml = molecular layer; pc = Purkinje cell layer; gc = granule cell layer; wm = white matter. Note focal pc loss in A2, and large zones of pc loss in A3 and A4. (Original Magnif
1
Software (GraphPad Software, Inc., San Diego, CA). Software generated significant P-values are shown in the graphs or included in the tables.ResultsEffects of NDEA and HFD on Serum Biomarkers of T2DM (Table 2)Tissue homogenates were prepared in radioimmunoprecipitation assay buffer containing protease and phosphatase inhibitors, as previously described [46]. Direct ELISAs were performed in 96-well
1
Ed, suggestive of increased myelin degeneration, in these two groups. Ubiquitin immunoreactivity was virtually undetectable in control and NDEA-exposed cerebella (Figs. 1-D1, 1-D2), but slightly increased in the Purkinje and granule cell layers of HFD-fed cerebella (Fig. 1-D3). Rats exposed to NDEA, and also chronically fed with the HFD, had prominently increased ubiquitin immunoreactivity in Purk
1
Ative stress with lipid peroxidation, as occur in AD. The finding that chronic HFD feeding did not significantly alter tau or AbPP expression also supports our previous conclusion that HFD feeding contributes to, but is not sufficient to cause AD-type neurodegeneration [45,46]. The combined effect of early, limited NDEA exposure plus chronic HFD feeding significantly reduced insulin and ChAT mRNA
1
Could serve as biomarkers of insulin-resistance mediated neurodegeneration. Finally, the findings suggest that our insulin resistance disease epidemics are linked to sub-mutagenicTong et al. BMC Endocrine Disorders 2010, 10:4 http://www.biomedcentral.com/1472-6823/10/Page 13 ofexposures to nitrosamines and related compounds, combined with chronic consumption of high fat content foods, indicating t