Effects of minocycline on biobehavior of human periodontal ligament cells in vitro

Objective To evaluate the influence of minocycline on the proliferation and biosynthesis of human periodontal ligament cells (HPDLCs) in vitro. Methods Various concentrations of minocycline (1,5,20,100,500,2500 mg/L)were added to the medium of cultured HPDLCs respectively. After co-incubated for 2 days, cell morphology was observed under reverse microscope, 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 H-TdR. Results The presence of minocycline not exceeding 500 mg/L in the medium resulted in no morphological change of HPDLCs. Moreover, at a concentration range of 5 to 100 mg/L, minocycline significantly enhanced the proliferative activity and biosynthesis of HPDLCs (P 0. 01 ). However, higher concentration (2500 mg/L) not only changed cell morphology under microscope, but also significantly inhibited cellular activity. Conclusions The results suggest that proper doses of minocycline could promote biobehavior of HPDLCs, while higher concentrations of minocycline had cytotoxic effect which may intervene affect tissue repair and regeneration.