Cell proliferation and synaptogenesis in the cerebellum after focal cerebral ischemia.
Cerebral ischemia induces cortical function reorganization and neocortical neurogenesis in the cerebral hemisphere. However, whether the cerebellum undergoes corresponding dynamic change after cerebral injury has not been determined. We investigated the characteristics of cell proliferation and synaptogenesis in the cerebellum after focal cerebral ischemia. After induction of focal cerebral ischemia in rats, bromodeoxyuridine (BrdU, 100 mg/kg, intraperitoneally, daily) was administered for 5 days. Brain sections were analyzed using immunohistochemistry at days 7, 14, and 28. BrdU+ cells and Iba-1+ cells were counted, and cerebellar synaptophysin immunoreactivity was quantitatively analyzed. Rats with cerebral ischemia showed increased numbers of BrdU+ cells in the cerebellum at day 28 compared to sham-operated rats. Neither neuronal markers nor GABAergic markers were co-labeled with BrdU+ cells, suggesting that none of the proliferating cells contributed to neurogenesis. Instead, the number of Iba-1+ cells in the cerebellum was increased, which suggests that microglia are activated in the cerebellum after cerebral ischemia. The optical density of synaptophysin in the cerebellum of rats with cerebral ischemia was significantly increased in the molecular and granular layers at days 7 and 14. Cerebellar synaptophysin expression was significantly correlated with cerebellar cell proliferation. This study shows that the cerebellum undergoes specific and dynamic changes at the cellular level after focal cerebral ischemia, including cell proliferation and synaptogenesis.
Jung
Se Hee
SH
Department of Rehabilitation Medicine, Seoul National University Boramae Medical Center, Seoul, South Korea.
Lee
Soon-Tae
ST
Chu
Kon
K
Park
Jung-Eun
JE
Lee
Shi-Uk
SU
Han
Tai-Ryoon
TR
Kim
Manho
M
D000818:Animals; D002545:Brain Ischemia / Q000473:pathology*; D002452:Cell Count; D049109:Cell Proliferation; D002531:Cerebellum / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000378:metabolism / Q000473:pathology; D016708:Synaptophysin / Q000378:metabolism*
D016708:Synaptophysin