Cyclic-stretch induces apoptosis in human periodontal ligament cells by activation of caspase-5.

BACKGROUND AND OBJECTIVE: As caspase-5 plays a role in apoptosis, the present study aimed to identify the expression and activation of caspase-5 in human periodontal ligament cells in response to cyclic stretch and the role of caspase-5 in stretch-induced apoptosis.

METHODS: Human PDL cells were exposed to 10% or 20% stretch strain for 6 or 24h, and the mRNA and protein expressions of caspase-5 were analyzed with real-time PCR and Western blot, respectively. The caspase-5 activation was detected by colorimetric assay. Then the influence of the inhibition of caspase-5 on the stretch-induced apoptosis and caspase-3 activation were analyzed with flow cytometry and colorimetric assay, respectively.

RESULTS: Both 6 and 24h stretches increased mRNA, protein expression and activation of caspase-5 in human PDL cells. Inhibition of caspase-5 inhibited the stretch-induced apoptosis and caspase-3 activation in human PDL cells.

CONCLUSION: This study for the first time identified the expression and activation of caspase-5 in cyclic stretched human PDL cells and found that the stretch-induced apoptosis and caspase-3 activation were caspase-5 dependent.