Abstract:

To observe lipopolysaccharide(LPS) induced apoptosis of human dental pulp cells(HDPC) and its effect on apoptosisrelated cystine protease 3 (caspase3), Bcl2, and Bax activity in vitro. MethodsPulp cells were stimulated with 0, 0.01, 0.10, 1.00, 10.00, 100.00?mg/L LPS. Then the cell proliferation activity was detected using MTT colorimetrics, the cell cycle and apoptosis after LPS stimulation using flow cytometry, and expressions of caspase3, Bcl2, Bax using immunocytochemical staining. ResultsCell growth was significantly inhibited by LPS in a dosedependent manner.  Flow cytometry results showed that  the apoptotic rates were respectively 3.1%, 3.5%, 12.1%, 14.4%, 24.3%, and 59.7% after stimulated by LPS. Immunocytochemical staining showed that Bax expression was increased, while caspase3 and Bcl2 expressions were decreased. ConclusionLPS could significantly inhibit the proliferation of HDPC, induces apoptosis, reduces Bcl2 and caspase3 activity, and increases Bax activity, which is dosedependent.

Key words: Dental pulp; Lipopolysaccharide; Apoptosis; Caspase3; Bcl2