Phosphorylation of retinoblastoma protein in rat brain after transient middle cerebral artery occlusion

• Published in: Neuropathology and applied neurobiology Vol. 26; no. 4; pp. 390 - 397
• Main Authors: Hayashi, T., Sakai, K., Sasaki, C., Zhang, W. R., Abe, K.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.08.2000; Blackwell Science
• Subjects: Animals; Apoptosis; Biological and medical sciences; Blotting, Western; brain; Brain - metabolism; Disease Models, Animal; Immunohistochemistry; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery - metabolism; Infarction, Middle Cerebral Artery - pathology; ischaemia; Ischemic Attack, Transient - metabolism; Ischemic Attack, Transient - pathology; Male; Medical sciences; Neurology; Neurons - metabolism; Neurons - pathology; Phosphorylation; rat; Rats; Rats, Wistar; retinoblastoma protein; Retinoblastoma Protein - genetics; Retinoblastoma Protein - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - metabolism; Signal Transduction; Vascular diseases and vascular malformations of the nervous system; Nervous system diseases; Phosphorylation; Pathophysiology; Rat; Rodentia; Middle cerebral artery; Retinoblastoma protein; Cardiovascular disease; Transitory; Cerebral disorder; Vascular disease; Vertebrata; Mammalia; Ischemia; Animal; Central nervous system disease; Cerebrovascular disease; Brain (vertebrata)
• ISSN: 0305-1846; 1365-2990
• DOI: 10.1046/j.1365-2990.2000.00264.x

Although mature neurones do not replicate genomic DNA, some cell cycle‐related kinases are aberrantly activated in neurones after ischaemia. As hyper‐phosphorylation of retinoblastoma (Rb) protein is the common pathway in mitotic signal cascade, this study investigated the phosphorylation state of the Rb protein as well as its mRNA level in rat brain after transient middle cerebral artery (MCA) occlusion. Immunohisto‐chemical analysis revealed that neurones in the sham‐operated brain expressed Rb protein without the hyperphosphorylated form. Immunoreactivity for the hyperphosphorylated form of Rb protein progressively increased from 1 h to 3 days after ischaemia in neurones in the MCA territory. Western blot analysis demonstrated a similar change. However, reverse transcription‐polymerase chain reaction study revealed that Rb showed no definite change at the mRNA level. These results suggest that Rb protein is progressively hyper‐phosphorylated in the brain after ischaemia, which may activate apoptotic mechanisms in neuronal cells of the brain after ischaemia.