Fig. 2.
The impairment of Kir4.1 channels expressed in NG2 glia leads to myelin loss in axons from tMCAO mice. (a and b) Representative traces show macroscopic currents and Ba2+-sensitive currents in NG2 glia in both contralateral (a) and ipsilateral (b) hippocampal CA1 regions of tMCAO. The arrow shows a dramatic loss of Ba2+-sensitive Kir4.1 current in ipsilateral NG2 glia after tMCAO. (c) Average I/V plot is for Ba2+-sensitive currents in NG2 glia after tMCAO. The error bars represent s.e.m. ∗∗∗p < 0.001, two-tailed unpaired t-test. n indicates the number of cells recorded. (d) Electron micrographs demonstrate the presence of impaired axons with demyelination in ipsilateral cortex compared with its contralateral region after 40 min tMCAO in wild type mice at postnatal 8 weeks. In contralateral cortex of tMCAO, axons show normal myelin, which exhibits dark, ring-shaped sheaths surrounding the axon. Scale bars: 2 μM. (e) Bar graph and G-ratio of myelinated axons represent the number of myelinated axons and G-ratio between ipsilateral cortex after tMCAO with its contralateral side. n indicates the number of axons from 4 wild type mice. (f) The box-plots represent average of myelin sheath thickness in both wild type mice and Kir4.1 deficient mice after tMCAO. The data were normally distributed and statistical significance was assessed within each group using Tukey–Kramer multiple comparisons test. ∗∗∗p < 0.001, n.s indicates not significant. The analyzed axons are from 4 mice per group. (g and h) Electron micrographs (g), bar graph and G-ratio of axonal diameter (h) show the demyelinated axons in both contralateral and ipsilateral hippocampus after 40 min tMCAO in Pdgfrα-CreER™;Kir4.1f/f mice at postnatal 8 weeks. Scale bars: 2 μM. (i) The box-plots represent the average of G-ratio of myelinated axons in both wild type mice and Kir4.1 deficient mice after tMCAO. The data were normally distributed and statistical significance was assessed within each group using Tukey–Kramer multiple comparisons test. ∗∗p < 0.01, ∗∗∗p < 0.001, n.s indicates not significant. The analyzed axons are from 4 mice per group.