Simulated orthodontic forces increased interleukin-1 beta mRNA transcript levels in human fibroblasts

Orthodontic tooth movement occurs due to the remodeling of periodontal ligament and bone. Periodontal ligament (PDL) cells are the primary cells that respond to orthodontic forces by expressing cytokines which effect other cells in a paracrine manner. Cytokines observed in response to orthodontic forces drives the osteoclastogenesis causing tooth movement. Among the cytokines reported, interleukin 1 β (IL-1β) has been mostly observed in gingival crevicular fluid in humans. The aim of the study was to determine the effect of four orthodontic forces on the mRNA level of IL-1β in human fibroblasts. Cell cultures of fibroblasts were seeded until confluent. Cells were harvested, counted and placed in a 3-dimensional culture with collagen type 1. Cells were subjected to simulated orthodontic forces of 20g, 60g, 120g and 200g by centrifugation. mRNA was extracted and quantified by real-time PCR. Student\u27s paired t-test was used for data analysis. IL-1β mRNA increased with an increase in simulated orthodontic force. The increase in the mRNA expression was statistically significant between control and experimental groups Specifically, IL-1β was significantly different between light and heavy forces. The study affirmed that IL-1β mRNA is expressed by human fibroblasts and that a direct relationship exists between the force and IL-1β mRNA transcript. These suggest that IL-1β may initiate the remodeling processes involved in orthodontic tooth movement