Details

Autor(en) / Beteiligte

• Zhang, Feng-Xiang
• Chen, Ming-Long
• Shan, Qi-Jun
• Zou, Jian-Gang
• Chen, Chun
• Yang, Bing
• Xu, Dong-Jie
• Jin, Yu
• Cao, Ke-Jiang

Titel

Hypoxia reoxygenation induces premature senescence in neonatal SD rat cardiomyocytes

Ist Teil von

• Acta pharmacologica Sinica, 2007, Vol.28 (1), p.44-51

Ort / Verlag

United States: Nature Publishing Group

Erscheinungsjahr

2007

Quelle

MEDLINE

Beschreibungen/Notizen

• Aim： To investigate whether hypoxia reoxygenation induces premature senescence in neonatal Sprague-Dawley （SD） rat cardiomyocytes. Methods： Cardiomyocytes were isolated from neonatal SD rat heart and identified by immunohistochemistry. The control cultures were incubated at 37℃ in a humidified atmosphere of 5% CO2 and 95% air. The hypoxic cultures were incubated in a modular incubator chamber filled with 1% 02, 5% CO2, and balance N2 for 6 h. The reoxygenated cultures were subjected to 1% O2 and 5% CO2 for 6 h, then 21% oxygen for 4, 8, 12, 24, and 48 h, respectively. Cell proliferation was determined using bromodeoxyuridine labeling. The ultrastructure of cardiomyocytes was observed by using an electron microscope. β-Galactosidase activity was determined by using a senescence β-galactosidase Staining Kit. p16^INK4a and telomerase reverse transcriptase （TERT） mRNA levels were measured by real time quantitative PCR. TERT protein expression was determined by immunohistochemistry. Telomerase activities were assayed by using the Telo TAGGG Telomerase PCR ELISA^plus kit. Results： The initial cultures consisted of pure cardiomyocytes identified by immunohistochemistry. The proportion of BrdU positive ceils was reduced significantly in the hypoxia reoxygenation-treated group （P〈0.01）. Under the condition of hypoxia reoxygenation, mitochondrial dehydration appeared; p 16^INK4a and TERT mRNA levels, β-galactosidase activity, TERT protein expression and telomerase activities were all significantly increased （P〈0.01 or P〈0.05）. Conclusion： These data indicate that premature senescence could be induced in neonatal SD rat cardiomyocytes exposed to hypoxia reoxygenation. Although TERT significantly increased, it could not block senescence.