Part 2: Cinnamon Extract Decreases Size and Lipid Volume In 3T3-L1 Preadipocytes Grown in Three-Dimensional Agarose Culture

In part 1 of the study, the 3D agarose model was presented for its use in 3T3-L1 cells. Growth in 3D agarose allowed 3T3-L1 preadipocytes to differentiate spontaneously without the chemical induction that is used to induce differentiation in monolayer cultures. Part 2 utilizes the previously published 3D agarose culture model to examine the effects of cinnamon extract on the 3T3-L1 cells. Here we report that the morphological changes associated with the 3D agarose cultured 3T3-L1 cells are not altered by the presence of cinnamon extract at the concentration tested. The treated cells remained round with accumulated lipid, as visualized with oil red O staining. However, a significant reduction in median cell size was noted in cultures treated with cinnamon extract. Differentiation was confirmed at all time points by both oil red O staining and immunohistochemistry detection of a known marker of differentiation, PPARγ. Results demonstrate that the decreased size of the cinnamon treated cells is associated with a decreased lipid volume, but only in cells grown in the 3D agarose culture. The same trend was not observed in monolayer treated cells. Modified monolayer experiments, designed to explore the effects of cell rounding on lipase activity, suggest that lipase activity is suppressed when rounded cells are treated with cinnamon extract, an observation that is not replicated in cinnamon treated flat cells. Extrapolation of this data suggests a possible use for cinnamon that could lead to reduced lipid volume storage in adipose cells, although additional studies should be conducted to determine safety and extraneous reactions possible by cinnamon.