Correlation of the expression level of C1q mRNA and the number of C1q-positive plaques in the Alzheimer disease temporal cortex analysis of C1q mRNA and its protein using adjacent or nearby sections
I. Tooyama et al., Correlation of the expression level of C1q mRNA and the number of C1q-positive plaques in the Alzheimer disease temporal cortex analysis of C1q mRNA and its protein using adjacent or nearby sections, DEMENT G C, 12(4), 2001, pp. 237-242
We compared the expression level of Clq mRNA and the number of Clq-positive
plaques in adjacent or nearby brain sections from Alzheimer disease (AD) a
nd control cases, Small blocks of temporal cortex were fixed wi th 4% paraf
ormaldehyde for 2 days at 4 degreesC. After cryoprotection with solutions c
ontaining 10-20% glycerol and 2% dimethylsulfoxide, 40-mum sections were cu
t from the tissue blocks. A section from each case was stained by immunohis
tochemistry using a C1q antibody, while RNA was purified from adjacent or n
earby sections using a combination of proteinase K pretreatment followed by
extraction using Trizol reagent. The expression of C1q B chain mRNA was an
alyzed in these samples by the reverse-transcription polymerase chain react
ion (RTPCR), The intensities of the PCR products were measured by an image
analyzer. The expression of C1q B chain mRNA was significantly more abundan
t in AD than in control cases (p < 0.05). Immunohistochemical analysis show
ed that C1q protein was localized in senile plaques in the AD brain. The nu
mber of C1q-positive plaques correlated with the expression level of C1q ge
ne (p < 0.05). The present results suggest that C1q protein in senile plaqu
es originates is endogenously produced in the AD brain. Copyright (C) 2001
S. Karger AG. Basel.