Brain Tissue Preparation for Enzyme Assays

After 2 and 9 months post-transplantation, brains were dissected sagittally along the midline, and left hemispheres were post-fixed overnight at 4°C in 4% paraformaldehyde (PFA) before cryoprotection at 4°C in a solution of 30% sucrose in Tris-buffered saline. The right brain hemispheres were further sectioned into 2 mm-thick coronal slices using an adult mouse brain slicer matrix (Zivic Instruments, Pittsburgh, PA) and rapidly frozen and stored at −80°C until performing NAGLU and β-hexosaminidase activity assays. 40-μm frozen coronal sections were cut through the rostrocaudal extent of the cortical mantle (Microm HM 430 freezing microtome, Thermo Fisher Scientific, Waltham, MA). Sections were collected in a cryoprotectant solution (tris-buffered saline [TBS]/30% ethylene glycol/15% sucrose/0.05% sodium azide) and stored at 4°C before histological processing.43 (link), 44 (link), 45 (link)