Human-Periodontal-Ligament-Fibroblasts subjected to pressure type force application up-regulated ADAMTS1-metalloproteinase gene

Background: Orthodontic-force-application (OFAP) on deciduous-teeth (DT) contains an inherent risk of root-resorption. This effect is hardly seen in permanent-teeth (PT). Currently, the mechanism of root-resorption-response is unknown. Objectives: 1)To achieve homogenous PDL-Fibroblast-cultures. 2)To establish an in vitro OFAP model with enhanced cell-vitality. 3)To compare gene-expression responses of DT and PT-PDL-fibroblast (D-PDLF,P-PDLF) following pressure-application. Methods: Cell-cultures were prepared from PDL of PT and DT with no successors, by immunomagnetic seclusion (MACS^®) of specific human fibroblast marker (D7-FIB) followed by FACS-analysis. Hydrostatic-pressure and cell-vitality were evaluated by Opticell^TM based model for OFAP. Gene expression of P-PDLF and D-PDLF under pressure for 24h, were compared by Gene-Array-analysis and verified using real-time-RT-PCR. Results: MACS^® treated cultures showed significantly higher D7-FIB-expression compared to untreated cultures (98% vs. 90%). An average of 94% cell-survival was observed in a series of increasing pressure loads and durations inside the Opticell^TM based model. Gene-Array showed higher up-regulation of ADAMTS1's mRNA in pressurized D-PDLF than in pressurized P-PDLF, when compared to untreated fibroblasts (x4.5 and x2.14, respectively, p<0.05). Real-time-RT-PCR-analysis verified elevated ADAMTS1's mRNA expression in pressurized PDLF compared with untreated PDLF. Conclusions: Immunomagnetic fibroblast seclusion is efficient for establishing homogenous cultures. The Opticell^TM OFAP model generated precise hydrostatic-pressure and excellent cell vitality. Up-regulation of ADAMTS1 during force application indicates its involvement in the remodeling of the periodontium. ADAMTS1's higher expression in pressurized D-PDLF compared to pressurized P-PDLF may explain the different DT and PT root-resorption response during OFAP. Understanding root resorption mechanisms will help prevent root resorption during orthodontic treatment.