Quantitative analysis of neurodegeneration (a) and gliosis (b) in GFAP-IL6 transgenic mice. A total of 17 mice were analyzed for selected markers utilized to assess the severity of the cellular neuropathology. GFAP-IL6 mice from both age groups were significantly different from nontransgenic controls on measures of MAP2-IR, parvalbumin-IR, and GFAP-IR. A significant loss of SYN-IR was observed in 3-month-old homozygous (tg/tg) transgenic mice and in both groups of 12-month-old transgenic mice when compared with controls, but not in 3-month-old heterozygous (+/tg) transgenic mice. The loss of calbindin-IR neurons and more intense microgliosis observed in 3-month-old heterozygous, and 12-month-old heterozygous and homozygous GFAP-IL6 mice, was significantly different from controls. Three-month-old heterozygous mice did not differ from controls on these measures. All values were expressed as percent increase or loss compared with age matched controls (mean ± SE). ∗, Significantly different from controls (P < 0.01). ∗∗, Twelve-month-old heterozygous mice were significantly different from 3-month-old heterozygous mice (P < 0.01).