Objective: The lumbar ligamentum flavum (LF) is an important part of the spine to maintain the stability of the spine. In this study we aimed to examine whether mechanical force by cyclic stretch could induce apoptosis in human LF cells and investigate the underlying mechanism.
Methods: LF cells were isolated from six young patients undergoing spinal surgery and then cultured in vitro. LF cells were subjected to cyclic stretch and the poptosis was detected by flow cytometry. The level of intracellular reactive oxygen species (ROS) and caspase-9 activity were measured.
Results: Cyclic stretch at a frequency of 0.5 Hz with 20% elongation induced the apoptosis of human LF cells in vitro, and this was correlated with increased ROS generation and activation of caspase-9.
Conclusion: Our study suggests that cyclic stretch-induced apoptosis in human LF cells may be mediated by ROS generation and the activation of caspase-9.
Keywords: Apoptosis; Caspase-9; Cyclic stretch; Ligamentum flavum; Reactive oxygen species.