[Hypoxia/reoxygenation induced endoplasmic reticulum stress in cultured neonatal rat cardiomyocyte].

Objective: To investigate the effect of hypoxia/reoxygenation on endoplasmic reticulum stress in cultured neonatal rat cardiomyocytes.

Methods: Neonatal rat cardiac myocytes in primary culture were exposed to hypoxia for 5.5 hours and subsequently reoxygenation for 2-24 hours. Western blot and RT-PCR were applied to monitor the expression change of GRP78 (glucose regulated protein 78). 2-deoxy-D-glucose (2-DG) was the positive control of this study. Then Western blot and RT-PCR were used to examine the expression of GRP78.

Results: Cell viability was decreased obviously after hypoxia/reoxygenation. Compared with untreated cells, the GRP78 content of the cells had increased significantly in the hypoxia/reoxygenation cells. The level of GRP78 protein and mRNA elevated from the points of 2 hours to 24 hours after reoxygenation, and increased most obviously at the point of 4 hours after reoxygenation. (4 hours: protein level 142% of the control, mRNA level 200%). 2-DG could induce the increasing expression of GRP78 in a concentration-dependent manner from 10-50 mmol/L.

Conclusion: Hypoxia/reperfusion can induce endoplasmic reticulum stress in rat cardiomyocytes.