Selective loss of basal forebrain cholinergic neurons in APP770 transgenic mice

Objective To determine whether cholinergic neurons in the basal nucleus magnocellularis (N BM) and the medial septum are affected in transgenic mice overexpressing human a myloid precursor protein 770 (APP(770)).Methods Eight age groups, from 3 months old to 10 months old, of either heterozygous tra nsgenic or non-transgenic mice were used for choline acetyltransferase (ChAT) s taining using immunohistochemistry. The number of ChAT-positive neurons was co unted on the MCID Image Analysis System. Neurons in the cerebral cortex and are a CA1 of hippocampus were also stained with cresyl violet and counted using opti cal dissector technique. Results There is no change in the number of forebrain cholinergic neurons in the transge nic mice up to 9 months of age. A loss of these cholinergic neurons starts in 9 months old transgenic mice, with a further decrease in the number of NBM and me dial septum neurons in 10-month-old transgenic mice. On the other hand, the n umber of neurons in the cerebral cortex and hippocampal area CA1 remained unchanged.Conclusion These results demonstrate a selective loss of basal forebrain cholinergic neuron s in APP(770) transgenic mice.