title: Dynamic changes of apoptosis and expression of Bcl-2 family members in the posthatch hippocampus of Bengalese finches.
abstract: The hippocampus of songbirds plays an important role in spatial memory, and probably in song learning. Although prolonged neuronal generation and apoptosis are thought to be closely correlated with memory function, natural changes of the number of neurons and in apoptosis in the hippocampus of songbirds have not been fully investigated during development and in the adult. In the current study, we examined developmental changes in the volume and the number of neurons and apoptotic cells in the hippocampus of songbirds (Lonchura striata) from posthatch day (P5) to adulthood. Apoptotic cells were determined by Nissl staining and immunohistochemistry for cleaved caspase-3, a key apoptotic caspase executioner. The expression levels of Bcl-2 family member mRNA and protein, including Bcl-2, Bcl-xL and Bax, were also investigated. Our results indicated that: (1) the hippocampus volume significantly increased from P5 to P60, although the number of neurons remained stable in all studied stages; (2) the number of apoptotic cells was highest at P45, based either on the Nissl staining or on the immunohistochemistry for caspase-3; (3) Bcl-2 mRNA expression was high from P5 to adulthood, while Bax mRNA declined abruptly from P5 to adulthood, and Bcl-x mRNA was high after P45. Bcl-2 protein was only detected at P5 and P15, while detection of Bcl-xL and Bax proteins paralleled levels of mRNA expression. Our study provides detailed changes of apoptosis in the posthatch songbird hippocampus, suggesting an important role for caspase-3 and Bcl-2 family members in hippocampus apoptosis.
authors.affiliation: College of Life Sciences, Beijing Normal University, Beijing 100875, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zeng
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Lu
authors.forename: Shaoju
authors.initials: S
authors.lastname: Zeng
authors.forename: Yutao
authors.initials: Y
authors.lastname: Lin
authors.forename: Yingyu
authors.initials: Y
authors.lastname: Sun
authors.forename: Xinwen
authors.initials: X
authors.lastname: Zhang
authors.forename: Mingxue
authors.initials: M
authors.lastname: Zuo
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D005260:Female; D046369:Finches; D015870:Gene Expression / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D009474:Neurons / Q000378:metabolism; D017711:Nonlinear Dynamics; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D053148:Caspase 3; D020169:Caspases