Effects of Passaging on the Migration Response of Synovium-Derived Stem Cells to an Applied DC Electric Field

Strategies for cartilage tissue engineering and repair have recently focused on cell sources from the surrounding joint tissue as an alternative to chondrocytes. Synovium-derived stem cells (SDSCs) are found in the intimal layer of the synovium, the thin overlying capsule surrounding the joint space [1] and have been found to exhibit a greater chondrogenic potential than stem cells from other origins such as bone marrow stem cells or adipose derived stem cells [2–4]. Under directed cues, these cells have been shown to be capable of migrating from the synovium membrane into articular cartilage defects, though the mechanism behind such movement is unclear. As a first step, we have previously shown that SDSCs expanded in 2D monolayer culture in a growth factor cocktail of TGF-β1, FGF, and PDGF-ββ exhibit directed cathodal migration with perpendicular alignment when under the influence of an applied DC electric field [5]. As cellular behavior and response to an external stimulus can change with exposure to growth factors and passage number, we look here to characterize the effects of passaging on the migration response of SDSCs to an applied electric field. We hypothesize that if these cells develop more chondrocyte-like characteristics with growth factor passaging, their response will mimic that which has previously been reported for chondrocytes, notably directed cathodal (negative pole) migration and perpendicular realignment of the long axis to the direction of applied field [6].