Sexual differences in cell proliferation in the ventricular zone, cell migration and differentiation in the HVC of juvenile Bengalese finch.
Song control nuclei have distinct sexual differences and thus are an ideal model to address how brain areas are sexually differentiated. Through a combination of histological analysis and electrical lesions, we first identified the ventricle site for HVC progenitor cells. We then found that there were significant sex differences in the cellular proliferation activity in the ventricular zone of the HVC, the number of migrating cells along the radial cells (positive immunoreactions to vimentin) and differentiation towards neurons. Through co-culturing of male and female slices containing the developing HVC in the same well, we found that the male slices could produce diffusible substances to masculinize the female HVC. By adding estrogen, an estrogen antagonist, brain-derived neurotrophic factor (BDNF) or its antibody into the culture medium, separately or in combination, we found that these diffusible substances may include estrogen and BDNF. Finally, we found that 1) estrogen-induced BDNF upregulation could be detected 48 hr after estrogen treatment and could not be blocked by a vascular endothelial growth factor (VEGF) receptor inhibitor and 2) the amount of VEGF mRNA expressed in the developing HVC and its adjacent area did not display any significant sex differences, as did the distribution of VEGF and laminin-expressing endothelial cells in the developing HVC. Because these findings are largely different from previous reports on the adult female HVC, it is suggested that our estrogen-induced BDNF up-regulation and the resultant sexual differentiation might not be mediated by VEGF and endothelial cells, but instead, may result from the direct effects of estrogen on BDNF.
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China; Department of Laboratory Medicine, The Third Affiliated Hospital, Guangzhou Medical University, Guangzhou, China.
Qiong
Q
Chen
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China; College of Life Sciences, Hainan Normal University, Haikou, China.
Xuebo
X
Zhang
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China.
Yueliu
Y
Zhao
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China.
Xin
X
Zhou
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China.
Lina
L
Sun
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China.
Shaoju
S
Zeng
Beijing Key Laboratory of Gene Resource and Molecular Development, Beijing Normal University, Beijing, China.
Mingxue
M
Zuo
College of Life Sciences, Hainan Normal University, Haikou, China.
Xinwen
X
Zhang
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation / Q000502:physiology*; D005260:Female; D046369:Finches; D053400:High Vocal Center / Q000166:cytology*; D008297:Male; D012727:Sex Characteristics