Figure 2

Effects of sevoflurane preconditioning on neuronal apoptosis after spinal cord ischemia reperfusion (IR) injury. (A) Representative micrographs of TUNEL staining (green) and DAPI (blue) in laminae IX of the ventral gray matter at 36 h after IR injury. Scale bars are 200μm. (B) Representative immunohistochemical localization of neurons (NeuN; green) and cleaved-caspase-3 (red) in laminae IX of the spinal cord at 36 h after IR injury. Arrows delineate colocalization. Scale bars are 100μm. Immunohistochemistry data showing that IR led to a decrease in neuronal number in the spinal ventral horn and an increased percentage of NeuN/cleaved-caspase-3-positive cells, suggesting the loss of neurons is partly a result of apoptosis. Pretreatment with sevoflurane and downregulation of MMP-9 by intrathecal injection of MMP-9 siRNA had neuroprotective effects reflected in decreased neuronal apoptosis. (C) Quantification of TUNEL-positive neurons in laminae IX of the ventral horn as averaged across three independent experiments. (D) Quantification of colocalized cells (cells with yellow signals) in laminae IX. (E) Representative western blot and quantitative protein analysis of cleaved caspase-3 in the spinal cord 36 h after surgery. Relative integral density values (IDVs) were calculated after normalizing to the sham group in each sample. All data are presented as mean±SEM (n = 8 per group). **P < 0.05 vs. sham group; ^##P < 0.05 vs. IR group.