Nissl staining and cell counting. A: Nissl Staining was evaluated around the ischemic cortex. In all MCAO groups, shrunken neurons with intercellular space enlarged were observed and many unstained regions were observed. Hydrogen saline treated at 3 h after reperfusion preserved Nissl positive cells up to 7 days. B: The number of cells was significantly higher in hydrogen saline group (*P< 0.05 vs. MCAO). (a, b, c, d, e, f, g, h, i: 100 ×; j, k, l, m, n, o, p, q, r: 200 ×; Scale bar: 20 μm).