Figure 8. Amyloid-related protein expression in needle stick brain tissue.

A: Western blot of tissue near and including a needle track, labelled with the 4G8 antibody (which labels Aβ peptide and precursor molecules such as APP). Protein samples (50 µg/lane) were processed from animals surviving 1 d, 3 d, 5 d, 7 d, 14 d and 30 d after the lesion. Lane C shows a sample from an unoperated (age-matched control) brain. Labelling at 4 kDa (monomeric Aβ) was not obtained. Twin bands were observed at 122 kDa, corresponding to the size of APP. Labelling at molecular weights characteristic of oligomers was obtained (20/15/12 kDa). These bands showed intensification above control (C) levels, most prominently at 3 d and 7 d. As expected, a 4 kDa band was observed for the Aβ_1–40 standard. B: Western blot of the same tissue, using the A11 antibody (which labels oligomeric Aβ). A11 labelling identified a single band at 100 kDa, presumed to be a pre-fibrillar form of oligomeric Aβ. GAPDH (37 kDa) was used as a loading control. C: Densitometry analysis of the A11 labelling in B, normalised to GAPDH. Labelling (for oligomeric Aβ) shows limited upregulation at 3 d and 5 d, and again in the older animals (A1 and A2). Error bars represent standard error of the mean, n = 4 separate experiments.