Augmented senile plaque load in aged female beta-amyloid precursor protein-transgenic mice

Transgenic mice (Tg2576) overexpressing human beta -amyloid precursor prote in with the Swedish mutation (APP695SWE) develop Alzheimer's disease-like a myloid beta protein (A beta) deposits by 8 to 10 months of age. These mice show elevated levels of A beta 40 and A beta 42, as well as an age-related increase in diffuse and compact senile plaques in the brain. Senile plaque load was quantitated in the hippocampus and neocortex of 8- to 19-month-old male and female Tg2576 mice. In all mice, plaque burden increased markedly after the age of 12 months. At 15 and 19 months of age, senile plaque load was significantly greater in females than in males; in 31 mice studied at 15 months of age, the area occupied by plaques in female Tg2576 mice was ne arly three times that of males. By enzyme-linked immunosorbent assay, femal e mice also had more A beta 40 and A beta 42 in the brain than did males, a lthough this difference was less pronounced than the difference in histolog ical plaque load. These data show that senescent female Tg2576 mice deposit more amyloid in the brain than do male mice, and may provide an animal mod el in which the influence of sex differences on cerebral amyloid pathology can be evaluated.