Increased RNA oxidation in motor neurons and oligodendrocytes of SOD1^G93A spinal cord at pre-symptomatic stage.

<p>Lumbar spinal cord sections from different ages of SOD1^G93A mice (<i>G93A</i>) and non-transgenic littermates (<i>WT</i>) were immunolabeled with 15A3 antibodies. The intensity of 15A3 immunofluorescence in SOD1^G93A mice was significantly increased at 45 days of age (D), further enhanced at 60 days of age (B, E), and then diminishes during the symptomatic stage (F, G, H), while only a very faint signal was detected in non-transgenic littermates (A, C). 15A3 immunoreactivity was prominent in the ventral horn motor neurons and the white matter oligodendrocytes (K, L), as identified by CC1 immunostaining (M). No increase of 15A3 immunofluorescence was observed in the brain sections (N, O). The immunoreactivity was diminished greatly by the RNase treatment (J) and when the antibody was pre-incubated with 8-OHG (I). Scale bar, 50 µm. (P) Statistical analysis of motor neuron 15A3 immunofluorescence intensity (n = 20). Asterisks indicate statistical significance compared with WT, 60 d (*<i>P</i><0.0001).