Novel Methods to Study Angiogenesis Using Tissue Explants

Tissue explants of skeletal muscles, brain, kidney, liver and spleen from mice were cultured using collagen gel. Electron microscopic observation revealed that formation of capillary tubes with pericyte-like cells occurred only from the tissue explant of skeletal muscles. The capillary tubes formed in the collagen gel were positive for tomato lectin and platelet/endothelial cell adhesion molecule (PCAM)-1 antibody. Formation of capillary tubes in the rat was more predominant than in the mouse. Plasmalemmal vesicles were clearly observed in the capillary tubes from rat tissue explant. Muscle fiber-type differences were also observed. In the soleus muscle, the formation of capillary tubes was predominant than the tibialis anterior muscle. Using this culture model from the rat soleus muscle, effects of α-isoproterenol (β-adrenergic receptor agonist) and low-frequency electrical stimulation were examined on the formation of capillary tubes and fine structures of skeletal muscle explant. The formation of capillary tubes was promoted by α-isoproterenol administration. At low-frequency electrical stimulation, the formation of capillary tubes was inhibited. Both α-isoproterenol and electrical stimulation reduced the degeneration of skeletal muscles. This culture method of skeletal muscles may provide a useful model that can examine the effects of various drugs and physical stimulations