Figure 6.

IEX-1 KO mice develop MDS after total body irradiation (TBI). Eight-week-old WT and IEX-1 KO mice were treated with a single low (3Gy) dose of radiation and platelet (A) and RBC (C) counts in circulation were monitored monthly for a total of 8 months post-TBI. Thrombocytopenia in the mice was functionally corroborated by prolonged bleeding times at 8 months post-TBI, in which the time in seconds (s) to the cessation of blood flow was recorded (B). Representative results of increased reticulocytes in IEX-1 KO mice after TBI are shown in comparison with non-radiated mice (D). Reticulocytes containing residual ribosomal RNA were readily recognized by new methylene blue staining, marked with a white star (E). Increased Howell-Jolly bodies (F) and extramedullary hematopoiesis indicated by splenomegaly (G) were demonstrated only in IEX-1 KO mice post-TBI. Granulocytic dysplasia in irradiated IEX-1 KO mice was shown by a hyposegmented neutrophil with clumped chromatin (Pseudo-Pelger-Huet cell) (H). Symbols represent individual mice and horizontal lines indicate the mean in B, D, F, and G. n= 12 for IEX-1 KO and 8 for WT mice in A and C. Original magnification 100× for E and 200× for H.