OBJECTIVETo explore the biological effects of tetracycline on cultured human periodontal ligament fibroblasts (HPDLFs).

METHODSIncreasing concentrations of tetracycline (1, 5, 20, 100, 500, 2500 microg/ml) were added to the medium of cultured HPDLFs, respectively. After co-incubated for 2 days, cell morphology was observed under reverse microscope, meanwhile, cell proliferation activity was assayed using MTT, the total amount of protein was detected with Coumassie Bright Blue method and DNA synthesis was measured by 3H-TdR.

RESULTSOver a concentration range of 1 to 100 microg/ml, cells demonstrated a normal appearance, spindle or fusiform shaped. Moreover, at a concentration range of 20 to 100 microg/ml, tetracycline significantly enhanced the proliferating activity and biosynthesis of HPDLFs (P < 0.01). However, higher concentration (2500 microg/ml) not only changed cell morphology, but also significantly inhibited cellular activity.

CONCLUSIONThe results suggested that proper doses of tetracycline could promote proliferation and biosynthesis of HPDLFs while higher concentrations of tetracycline had cytotoxic effect.