[39]

   This study evaluated in vitro the differences in morphological behaviour between fibroblast cultured on smooth and microgrooved substrata (groove depth: 0.5 mm, width: 1 mm), which were subjected to simulated microgravity in a Random Positioning Machine (RPM) for 30m, 2h, and 48 hours. The aim of the study was to clarify which of these parameters was more dominant to determine cell behaviour. Analysis of the cellular response ranged from scanning electron and fluorescence microscopy to cell molecular analysis. Microscopy and image analysis showed that the fibroblasts aligned along the groove direction on all textured surfaces. On the smooth substrata, cells had spread out in a random fashion. The alignment of cells cultured on grooved surfaces under simulated microgravity, after 48 hours of culturing appeared similar to those cultured at 1g, although cell shape was different. Analysis of variance proved that all main parameters: topography, gravity force, and time were significant. In addition, gene levels were reduced by simulated microgravity particularly those of b3-integrin and collagen, however alpha-1 and beta-1 integrin levels were up-regulated. ERK1/2 was reduced in RPM, nonetheless, JNK/SAPK and p38 remained active. The members of the small GTPases family were stimulated under microgravity, particularly RhoA and Cdc42. 

(Supported by NWO-SRON: MG-057 & MG-063)