Physiome and pathophysiome research projects for studying cooperative functions of interstitial space and lymphatic system.

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We have designed and constructed a modified intravital microscope system for investigating murine lymphatic pump activity in vivo and developed a custom organ chamber with a semi-circular channel, being suitable for superfusion of murine mesentery in vivo. Using the new experimental appratus, we have evaluated whether or not thore is rhythmic pumping activity of murine mesenteric lymphatic vessels in vivo. A marked lymphatic pumping activity was observed in the mesenteries of DDY mice, The maximal and minimal diameter and frequency in the pumping activity were 60.9±1.0μm, 53.7±1.8μm and 12.8 min, respectively. Physiological roles of endogenous nitric oxide (NO) in the lymphatic pump activity in vivo were studied using the new appratus. A 15-min superfusion of 30μM-NAME in the mesenteries caused significant increasing the pumping frequency and the pump flow index and a significant decrease of the endo-diastoric and end-systolic diameters. Simultaneous superfusion of 1mM L-arginine with … More 30μM L-NAME produced a signficant reversal of the L-NAME-mediated increase of the frequency and decreace of the end-systolic diameter.We have attempted to examine whether the cultured lymphatic emdothelial cells, similar to angiogenesis of the blood vessels, have an ability to induce in vitro neovascularization of lymph vessels in response to basic fibroblast growth factor (bFGF). The effects of bFGF on the proliferation and migration of the cultured lymphatic endothelial cells isolated from dog thoracic ducts were evaluated by changing the number of the subconfluent cells and by wound migration assay, respectively. The effects of bFGF on invasion and tube formation of the cultured lymphatic endothelial cells into a three-dimensional collagen gel were also investigated by a phase-contrast microscope and an electron microscope. The 10ng/ml bFGF caused a significant induction of proferation and migration of the cultured lymphatic endothelial cells. The bFGF produced significantly invasion and tube formation of the cultured cells into a three-dimensional collagen gel. The bFGF also facilitated to form capillary-like tubes of the cultured cells between twe layers of collagen gets. These findings suggest that the cultured lymphatic endothelial cells have an ability to form lymphatic capillary-like tubes in response to bFGF. Less