Fig. 4.

Nell-1^Wnt1KO young adult mice develop postnatal hydrocephalus. a The gross appearance of the whole body and b skulls of young adult WT and affected Nell-1^Wnt1KO mice (P32) showed classic dome-shaped heads in KO specimens. The skull length (Anteroposterior length, AP), skull height, and body length were measured, showing significant features of hydrocephalus; c Micro-CT imaging with color-coded bone density heat-maps showed distinct decreases in the size and mineral density of the frontonasal bones, defects of the frontal bones (*), widened cranial sutures, premature ossification of the intraphenoidal synchondrosis (ISS, red arrow) and sphenoid-occipital synchondrosis (SOS, yellow arrow) in hydrocephalic Nell-1^Wnt1KO mice compared with WT controls; d 2D coronal and sagittal X-ray images demonstrated an enlarged hydrocephalic skull profile and premature ossification/fusion of the synchondrosis in the cranial base (arrows) in Nell-1^Wnt1KO mice; (e) Histologically, the typical morphological changes of the dilated brain ventricles (*) and the compressed brain cortex in hydrocephalus were revealed from the sagittal and coronal views. f At the cellular level, the composition of the cartilaginous matrix corroborates the ossified synchondrosis observed in hydrocephalic Nell-1^Wnt1KO mice as compared to WT controls; (g) stronger OCN immunostaining was observed in the hydrocephalic samples over WT controls; h The swollen epithelial cells of the choroid plexus were readily observed in hydrocephalic Nell-1^Wnt1KO specimens; i Immunohistochemistry of the markers of epithelial cell of the choroid plexus, prealbumin, and the ependymal cells, vimentin, were performed respectively. The misplaced expression pattern of vimentin was observed in hydrocephalic Nell-1^Wnt1KO specimens; (j) Immunohistochemistry of Pit-2 exhibited dysregulation among CP epithelial and ependymal cells of the dilated brain ventricle and the fourth ventricle in hydrocephalic Nell-1^Wnt1KO specimens. *P < 0.05; ****P < 0.001; n = 6 for a and b; n = 3 for i and j