Molecular pathological alterations in the brains of GFAP-IL6 transgenic mice. (a) RNase protection assay of poly(A)+-enriched RNA isolated from the brain of nontransgenic (+/+), heterozygous GFAP-IL6 (+/tg), or homozygous (tg/tg) GFAP-IL6 transgenic mice. (b) While cerebral expression of the ICAM-1, Mac-1, EB22/5.3, and GFAP genes was increased in GFAP-IL6 mice, quantitative analysis revealed a marked difference in the levels of expression of the Mac-1 and EB22/5.3 genes between heterozygous and homozygous GFAP-IL6 mice at 3 months but not at 12 months of age. ∗, For ICAM-1, a value of 1 arbitrary unit was assigned to the 3-month-old control group because there was no detectable ICAM-1 signal in these mice.