In addition to increased expression of GFAP, reactive astrocytes exhibit cellular hypertrophy. We found that most GFAP+ cells in the injured cortices of Mlc1-dnEGFR mice were smaller than those in control mice (Figure 2a). Quantitative analysis showed that despite a similar distribution of GFAP+ cells (Figure 2b), reactive astrocytes with a GFAP-immunoreactive area larger than 300 μm2 were significantly reduced in Mlc1-dnEGFR cortices at several time points after injury (Figure 2c). Consistently, WB showed that the increase in GFAP protein levels in injured cortical tissues from Mlc1-dnEGFR mice was 60.74±23.5% of that from littermate controls (Figure 2d). Reduction of GFAP was caused by an inhibition on GFAP gene transcription, and mRNA level of gfap splicing isoform 1 was significantly reduced (Figure 2e).