Abstract
Objective: To visualize and analyze spatiotemporal dynamics of individual living monocyte during transendothelial migration (TEM). Methods and Results: We developed a new experimental system to observe TEM with following two improvements. (1) Ultra thin collagen gel layer (30-50 μm thick) constructed under endothelium for 3D observation with high magnification. (2) Appropriate fluorescent labeling of living monocytes and endothelial cells to keep highest cell activity. Individual monocyte behaved quite diversely. About 70% of adhered monocytes directionally crawled to intercellular junction. Time from adhesion to start of invasion was 8.6±5.4 min (n=61 monocytes). However, remaining 30% did not transmigrate. Some of them could not find the invasion spot despite actively crawled on endothelium. Time from start to finish of invasion was 6.3±3.2 min (n=53 monocytes). About 20% of once invading monocytes hesitated transmigration, and returned onto endothelial surface. Conclusions: Using our new system, we visualized and quantitatively analyzed for the first time detailed spatiotemporal, 3D dynamics of individual living monocyte during TEM. Complete transmigration of individual monocyte could be achieved only when both vitality of the monocyte and the local condition of endothelium constructively couple together to proceed TEM. [Jpn J Physiol 54 Suppl:S93 (2004)]
