title: Structural features of bone marrow.
abstract: OBJECTIVE
  This article is devoted to the investigation of the structural features of the bone marrow of mature rats.
  
  
  METHODS
  The investigation of the structural features of the bone marrow was performed on the femurs of the mature male rats. General structure of the organ was studied with hematoxylin-eosin and Van Gieson staining of samples. Certain features of the bone marrow structure were studied using immunohistochemical method (CD3, CD79α, S100, myeloperoxidase, and cyclin D1).
  
  
  RESULTS
  We can state that stromal-parenchymal structure is typical for the bone marrow of rats as for any other organ. The stromal component is presented with bone tissue (48.8 ± 3.3% at epiphyses), the net of blood vessels (18.7 ± 2.1%), fat tissue (11 ± 2%), fibrous tissue (0.7 ± 0.2%), and the network of reticular fibers. Hematopoietic tissue covers 20.9 ± 3.7% at the femoral epiphyses and 69.6 ± 2.2% at diaphysis. Among these tissues, myelopoiesis occupies 74.2 ± 4.7%, erythropoiesis - 24.3 ± 4.7%, and lymphopoiesis - less than 5%. Megalokaryocytes take 0.1-0.3%.
  
  
  CONCLUSIONS
  Considering the lack of significant anatomical, morphological, and histological differences of red bone marrow of rats and humans, we can state that hematopoiesis in rats takes place on the basis of the same principles as in humans, although it has certain mechanisms.
authors.affiliation: Department of Pathology, Sumy State University , Sumy, Ukraine.
authors.forename: Anatolii
authors.initials: A
authors.lastname: Romaniuk
authors.affiliation: Normal Anatomy Department with a Topographical Anatomy and Operational Surgery Course, Sumy State University , Sumy, Ukraine.
authors.forename: Yuliia
authors.initials: Y
authors.lastname: Lyndina
authors.affiliation: Department of Pathology, Sumy State University , Sumy, Ukraine.
authors.forename: Vladyslav
authors.initials: V
authors.lastname: Sikora
authors.affiliation: Department of Pathology, Sumy State University , Sumy, Ukraine.
authors.forename: Mykola
authors.initials: M
authors.lastname: Lyndin
authors.affiliation: Department of Pathology, Sumy State University , Sumy, Ukraine.
authors.forename: Ludmyla
authors.initials: L
authors.lastname: Karpenko
authors.affiliation: Foreign Languages Department, Sumy State University , Sumy, Ukraine.
authors.forename: Oksana
authors.initials: O
authors.lastname: Gladchenko
authors.affiliation: Sumy State University , Sumy, Ukraine.
authors.forename: Igor
authors.initials: I
authors.lastname: Masalitin
keywords: bone marrow; erythropoiesis; immunohistochemical method; lymphopoiesis; megalokaryocytes; myelopoiesis