Fig. 5. CS-GAGs are required for proliferation of neural precursor cells during forebrain development. (A,B) Photomicrographs of immunohistochemical stainings of E14.5 mouse forebrain cryosections 1 day after ventricular injection with ACSF control (upper panels) or ChABC (lower panels). Cell nuclei were counterstained with bisbenzimide and are shown in blue (DAPI). (A) The dividing progenitors were identified by PH3 immunoreactivity. Note that ChABC treatment caused a significant reduction in the number of neural precursor cells undergoing mitosis. (B) The actively cycling cell population was labeled with BrdU. Note that ChABC treatment caused a significant reduction in the number of neural precursor cells undergoing S phase. (C) Quantification of the total number of PH3-positive cells in selected cortical and striatal (GE) areas revealed a significant reduction in the ChABC-injected (light gray) in comparison with the control-injected (dark gray) embryos (upper panel). ChABC treatment also altered the distribution of the neural precursor cells (lower panel). Note that significantly more cells were in M phase at the ventricular surface in control-injected brains. (D) Quantification of the total number of BrdU-positive cells in defined cortical and striatal (GE) areas revealed a significant reduction in the ChABC-injected (light gray) in comparison with the control-injected (dark gray) embryos (upper panel). Note that in ChABC-injected forebrains, more BrdU-positive cells were located in layers of the VZ/SVZ more distant to the ventricular surface (lower panels). Cor, cortex; ge, ganglionic eminence; lv, lateral ventricle. ^*, P<0.05; ^**, P<0.01; ^***, P<0.001. Scale bars: 100 µm.