Histological abnormalities in FUS/TLS KO mice. (a, b) HE-staining of TLS WT and KO mouse sections at 8 weeks of age. Vacuole-like structures were found in CA3 and the hilus regions of the knockout animal. Scale bar: 500 μm. (c) Magnified image of the vacuolar structures in a KO animal. Scale bar: 10 μm. (d) Electron microgram of a vacuolar structure in a 12 week-old TLS KO animal. Scale bar: 5 μm. (e) Electron microgram of the inside of vacuole-like structure in a KO mice. Scale bar: 1 μm. (f) Electron microgram of a dark cell found in a 12 week-old KO animal. Scale bar: 5 μm. Scale bar: 10 μm.