Nissl and TUNEL staining (A) of cerebral cortex and cell counting (B) at 72 h following SAH. (A) Representative slides of Nissl staining (A1-D2) and TUNEL staining (A3-D4) at two different magnifications (A1–D1, A3–D3: ×100; A2–D2, A4–D4: ×400). In the control group of Nissl staining (A1, A2), the neuronal cell outline was clear and the structure was compact with abundant cytoplasm and Nissl body. However, evident neuronal loss and neuronal degeneration were observed in the SAH group (B1, B2) and SAH + saline group (C1, C2). Cells arranged sparsely and the cell outline was fuzzy. The cells with eumorphism were significantly reduced. Compared with SAH or SAH + saline group, administration of hydrogen-rich saline substantially increased the proportion of survived neurons (D1, D2). TUNEL staining (A3-D4) showed that the rabbits in the control group display rare apoptotic neurons in the cortex (A3, A4), while obvious TUNEL positive neurons with intense nuclear stained as brown could be observed in the SAH group (B3, B4) or SAH + saline group (C3, C4). In contrast, the proportion of apoptotic neurons decreased significantly in the SAH + hydrogen-rich saline group (D3, D4). (B) Cell counts per visual field (×400) found in the slides with Nissl staining (b1) and TUNEL staining (b2). (b1) #P < 0.05 compared with control group; *P < 0.05 compared with SAH or SAH + saline group. (b2) ##P < 0.05 compared with control group; **P < 0.05 compared with SAH or SAH + saline group.