Figure 7.

Representative coronal sections from nNOS^−/− mice (A) and eNOS^−/− mice (B) and their respective wild-type controls were stained for apoptosis using Apoptag Peroxidase in situ Apoptosis Detection kit as described in Materials and Methods. The number of cells undergoing apoptosis in the corpus callosum of nNOS^−/− mice fed with cuprizone was significantly lower than that in wild-type mice. Scale bar, 25 μm. Effects of the lack of nNOS (C) and eNOS (D) genes on the accumulation of OPCs in response to cuprizone feeding. OPCs detected using NG2 antibody accumulate in the demyelinating corpus callosum in wild-type mice after 3 and 4 weeks of cuprizone treatment. Few NG2-positive cells were observed in the corpus callosum of nNOS^−/− mice in response to the neurotoxicant. NG2-positive cells were quantified as described in Materials and Methods. Scale bar, 25 μm. *p < 0.05; **p < 0.01.