Fig. 3.

Effect of perinatal asphyxia on apoptotic-like cell death in mesencephalon of rat neonates, 24 h after delivery: prevention by systemic nicotinamide treatment. Caesarean-delivered control (CS) and asphyxia-exposed (AS) rats were anaesthetized and transcardially perfused with buffered saline and a formalin solution 24 h after delivery. DNA fragmentation was evaluated in coronal brain sections (20-μm thick) with the TUNEL assay, counterstained with methyl green. The number of TUNEL-positive cells per mm³ was determined in substantia nigra (SN), and ventral tegmental area (VTA). a Representative microphotographs, from SN of control and asphyxia-exposed animals; TUNEL-positive cells are brown (arrows) (bar 10 μm). Inset shows a section from Foster atlas (1998), indicating the sampling area (white rectangles). b TUNEL-positive cells were manually counted on the stage of a Nikon TS100 microscope (magnification ×100), expressed as number of TUNEL-positive cells/mm³ in CS and AS animals, or in parallel animal series following a single dose of nicotinamide (0.8 mmol/kg, i.p.) (CNam, ANam) or saline (0.1 ml, i.p.) (CSal, ASal) 1 h after delivery; also fixed at 24 h (CSal open columns; CNam dashed columns, ASal grey columns, ANam doubled dashed columns). Pair-wise comparisons analysed with Student t test (*p < 0.05; n = 4–5, for each condition)