Protective Effects of Salidroside on Hypoxia/Reoxygenation Injury by Sodium Hydrosulfite in PC12 Cells

Abstract

Hypoxia/reoxygenation causes cellular injury and death associated with many pathophysiologic conditions, including respiratory disorders, myocardial ischemia, and tumour progression diseases. Neuronal pheochromocytoma (PC12) cells are widely used as a model system for neurologic research and are subject to chemical hypoxia induced with sodium hydrosulfite (Na₂S₂O₄), a common oxygen-consuming agent. Salidroside, which is the main active component of the famous traditional Chinese herb Rhodiola rosea. L. (Crassulaceae), has been proved to possess many bioactivities. In this article, we studied the protective effects of salidroside on hypoxia/reoxygenation injury in PC12 cells induced by Na₂S₂O₄. Cultures of PC12 cells were exposed for 1 h to 10 mM Na₂S₂O₄ for hypoxia, followed by reoxygenation for 2 h. The results showed that salidroside was very stable in medium and was not harmful to PC12 cells at the experimental concentrations of 0 ∼ 200 µg/mL. The cytoprotection by salidroside was dose-dependent, and the cell viability was 41.8 ± 5.7%, 62.4 ± 4.1%, and 92.2 ± 3.7% at 0, 50, and 100 µg/mL of salidroside, respectively. The level of released LDH significantly decreased from 513.5 ± 5.5% (without salidroside) to 258.1 ± 6.3% (with 100 µg/mL salidroside). Flow cytometry was performed to measure apoptotic rate. The results of flow cytometry assay indicated that the apoptotic rate was 17.0 ± 1.2% after hypoxia/reoxygenation injury. When the cells were treated with salidroside 12.5, 50 and 100 µg/mL, the apoptotic rate was 9.5 ± 0.9%, 7.4 ± 0.5%, and 4.5 ± 0.4%, respectively. In addition, our results were confirmed by inspection of cell morphology of PC12 cells. Treatment with salidroside (12.5, 50, 100 µg/mL) significantly prevented the cells from morphologic changes. All the above results showed salidroside could effectively protect PC12 cell against hypoxia/reoxygenation injury.

Keywords:

• Hypoxia/
• reoxygenation, Na₂S₂O₄, PC12 cells, salidrosid