Ts65Dn mice develop megakaryocytic myeloproliferative disease. (A) Complete blood counts (CBCs) are altered in Ts65Dn peripheral blood in comparison with euploid littermate controls. MCV indicates mean corpuscular volume; RBC, red blood cells. n = 14 Ts65Dn; n = 22 euploid same sex littermates. P < .05 for all parameters at all time points. Complete actual values and statistics are provided in Table S2. Error bars represent SE. (B) Hematoxylin and eosin staining of bone marrow and spleen sections (left and middle panels, respectively) highlight megakaryocyte hyperplasia in Ts65Dn animals, while reticulin staining reveals bone marrow fibrosis (right panels). indicate megakaryocytes; indicate reticulin fibrosis. All images were captured at 200× original magnification.