Pregnancy alters the proliferation and apoptosis of mouse splenic erythroid lineage cells and leukocytes.
Pregnancy induces dynamic changes in the maternal environment that include reversible modifications in response to systemic mediators and local signals. The spleen can be used to determine the effects of pregnancy on multiple cellular populations, including those of the erythroid lineage and the immune system. Current evidence suggests that the transient increase in the size of the spleen during pregnancy is due to the expansion of erythroid precursors. However, it is unclear what factors contribute to this increase. Moreover, the additional erythroid cells may compete with neighboring leukocytes for growth factors or space, and this may in turn alter the function of these populations. Therefore, we assessed proliferation and apoptosis throughout gestation using in vivo bromodeoxyuridine incorporation and the TUNEL assay, respectively. Here, we show that erythroid-lineage TER-119(+) cells expanded significantly in midgestation because of enhanced proliferation and diminished apoptosis. This correlated with increased expression of the erythropoietin receptor (Epor) and decreased expression of the death receptor Fas, respectively. Leukocytes demonstrated population-specific responses. Natural killer cells proliferated in early pregnancy. Both lymphocytes and CD11B(+) cells underwent enhanced proliferation during midgestation. In contrast, neutrophils exhibited augmented proliferation throughout pregnancy. These subset-specific alterations in proliferation and death in the spleen suggest that complex regulation of population dynamics exists during pregnancy.
Department of Obstetrics, Gynecology, and Reproductive Sciences, The University of Vermont College of Medicine, Burlington, Vermont 05405, USA.
Michelle T
MT
Norton
Karen A
KA
Fortner
Peyman
P
Bizargity
Elizabeth A
EA
Bonney
D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D001772:Blood Cell Count; D001789:Blood Group Antigens / Q000378:metabolism; D019070:Cell Lineage / Q000502:physiology; D049109:Cell Proliferation; D041905:Erythroid Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D005865:Gestational Age; D007962:Leukocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009929:Organ Size; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood / Q000276:immunology / Q000502:physiology; D013154:Spleen / Q000033:anatomy & histology
D001789:Blood Group Antigens; C489122:TER-119 antigen, mouse