The animals were transcardially perfused with 4% paraformaldehyde and 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer (pH 7.4) under deep anesthesia prior to sacrifice on day 3 after operation. After perfusion, about 1 × 1 × 1 mm3 brain blocks were collected from the perihematomal regions of the animals. Afterward, the blocks were immersed in 2.5% glutaraldehyde for 2 h at 4°C. In subsequence, the samples were fixed with 1% OsO4 and then dehydrated in ethyl alcohol. Following infiltration with propylene oxide, the samples were embedded in Eponate and sectioned. Then, the sections were stained with 2% uranyl acetate and Reynolds' lead citrate. The TEM images were captured using a TEM (Philips, Amsterdam, The Netherlands).