• Home
  • Search Results
  • The detection of β-amyloid plaques in an Alzheimer's disease rat model with DDNP-SPIO.

The detection of β-amyloid plaques in an Alzheimer's disease rat model with DDNP-SPIO.

Clinical radiology (2014-12-03)
D Zhang, H-B Fa, J-T Zhou, S Li, X-W Diao, W Yin
ABSTRACT

To detect the β-amyloid plaques (Aβ) in a rat model of Alzheimer's disease (AD) using superparamagnetic iron oxide nanoparticles coated with 1,1-dicyano-2-[6-(dimethylamino)-naphthalene-2-yl] propene carboxyl derivative (DDNP-SPIO). DDNP-SPIO was prepared in a previous trial. The binding affinity of DDNP-SPIO to Aβ was tested using fluorescence spectrophotometry in vitro. In vivo, five AD rats and five non-AD rats were intravenously injected with DDNP-SPIO at a dose of 76 μmol Fe/kg. Coronal T2*-weighted images were collected at baseline and repeated at 10, 30, and 60 min post-injection. Enhancement features of the two groups were analysed. After imaging, brain specimens were resected for Congo red and Prussian blue staining to assess the binding of DDNP-SPIO to Aβ deposits. In vitro experiments indicated that the DDNP-SPIO nanoparticles displayed high binding affinities towards Aβ with a Kd value of 29.4 nmol/l. A significant decrease in SI was detected in the hippocampal area of AD rats after intravenous injection of the nanoparticles, but not in non-AD rats. The measurement of the percentage signal loss decreased to 52% in AD rats. In non-AD rats, only 10% signal loss was observed. There was a significant difference between the two groups (t = 4.533, p < 0.05). The signal decrease resulted from the binding of the DDNP-SPIO nanoparticles to the Aβ plaques, which was identified with Congo red and Prussian blue staining. The DDNP-SPIO nanoparticles could potentially be used for visualizing Aβ plaques, which may be helpful for diagnosing the early stages of AD and monitoring the effects of drug therapy.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acrylonitrile, ≥99%, contains 35-45 ppm monomethyl ether hydroquinone as inhibitor
Sigma-Aldrich
Congo Red, Dye content ≥35 %
Sigma-Aldrich
Congo Red, certified by the Biological Stain Commission, BioXtra
Sigma-Aldrich
Iron(III) ferrocyanide
Sigma-Aldrich
2-Naphthylamine, powder
Sigma-Aldrich
Acrylonitrile, ≥99%, contains 35-45 ppm monomethyl ether hydroquinone as inhibitor
Supelco
Acrylonitrile, analytical standard
Supelco
Congo Red, analytical standard
Supelco
2-Naphthylamine, analytical standard
Supelco
Acrylonitrile solution, certified reference material, 5000 μg/mL in methanol