Related Experiment Video
Updated: Jun 18, 2026

Application of Aorta-gonad-mesonephros Explant Culture System in Developmental Hematopoiesis
Published on: November 3, 2017
Extramedullary hematopoiesis is dysregulated in histamine-free histidine decarboxylase knockout (HDC-/-) mice
Zsuzsanna Horváth1, Eva Pállinger, Gyozo Horváth
1Department of Genetics, Semmelweis University, Nagyvárad tér 4, 1089 Budapest, Hungary.
Objective And Design:
In this study we investigated the role of histamine on the extramedullary hematopoiesis.
Methods:
Male histidine decarboxylase knockout (HDC(-/-)) mice and wild-type mice were used (n = 5/group). Groups of mice received sublethal total-body gamma irradiation at a single dose of 4 Gy. Spleen cells were studied at different time points post-irradiation by flow cytometry, colony forming unit (CFU) assay, and real-time PCR. For statistical analysis Student's t test, ANOVA, and Holm-Sidak post-hoc test were used.
Results:
By day 14 after irradiation, spleen cell counts increased almost eightfold in wild-type and not even fourfold in HDC(-/-) mice (P < 0.01). The proliferative capacity and interleukin-3 signaling of stem cells were impaired in HDC(-/-) mice. STAT5 mRNA expression was decreased in granulocyte-myeloid colonies by 72.9 +/- 8.6% (P < 0.001), compared to the wild-type.
Conclusions:
The absence of histamine adversely affects splenic hematopoiesis via direct and indirect mechanisms.
Related Concept Videos
Regulation of Hematopoietic Stem Cells
Hematopoiesis
Multipotency of Hematopoietic Stem Cells
Hedgehog Signaling Pathway
Overview of Hematopoiesis
Developmental Phases of Hematopoiesis
Initially, HSCs are formed in the embryonic yolk sac, a critical site for early blood cell production. These stem cells subsequently migrate to other...

