Effects of GA on PrPSc accumulation in scrapie-infected mouse spleens at mid-incubation.
Transgenic mice overexpressing ovine PrP (tg338 line) were intraperitoneally infected with scrapie (127S strain) and treated with GA by the same route. Two independent experiments (shown respectively in panels a and b) have been performed, in which the dose and overall number of treatments varied, as indicated. Dextran Sulfate 500 (DS500, a) or GA solvent alone (5% glucose, a and b) served as positive and negative controls, respectively. In each treated group, triplicates of healthy mice were euthanized ∼50 days post-infection and the rate of PrPSc detectable in their spleens was determined by Western blot (see Materials and Methods). The same amount of spleen tissue material has been loaded on the gels. For each triplicate, Western blot of spleen PrPSc and densitometric quantification are shown. Each dot of the graph represents the PrPSc content of a single spleen. The dark horizontal line is the mean value. Statistical significance (p) was assessed using the non-parametric Kruskal-Wallis test. ns: not significant. Note that GA did not significantly affect spleen PrPSc level, although it showed a beneficial effect on mouse survival in both sets of independent experiments (see Table 1).