[Internalization of beta amyloid protein in primary cultured cortical neurons in mouse]

To observe the internalization of beta-amyloid protein (Abeta) in primary cultured neurons and effect of astrocyte on it.

The purified cortical neurons of mouse were cultured for 14 d, and were divided into a control group and an Abeta group. Each group was further divided into 3 subgroups. The neurons and 3 different concentration fluorescein or Abeta1-42-fluo were co-incubated for 24 h. The internalization of Abeta and the location of Abeta in subcellular structure were examined by the laser scanning confocal microscope combined with the image analysis method directly or after immunofluorescence staining. Neurons and astrocytes were co-cultured for 14 d. The cultured neurons and astrocytes were divided into a control group and a Abeta group. The cultures were treated with 200 nmol/L fluorescein or 200 nmol/L Abeta1-42-fluo for 24 h respectively. The effect of astrocyte on the internalization was analyzed by the above method.

There were no fluorescent granules within neurons in every fluorescein group. The purified cortical neurons could internalize 100 nmol/L, or 200 nmol/L Abeta1-42-fluo in 24 h. The fluorescent granules of Abeta1-42 distributed within perikaryon and processes. The internalization was related to the concentration of Abeta. The part of Abeta was located in the lysosome of neurons indicated by immunofluorescence staining. Compared with the purified neurons, the neurons co-cultured with the astrocytes internalized Abeta increased in the internalization of Abeta. There was significant difference between the purified neurons and the co-cultured neurons with astrocytes (P<0.05).

Neurons could internalize the proper concentration of Abeta. Astrocyte might facilitate the internalization of Abeta in neurons.