| Abstract: | Regeneration of lymphatic vessels after transection of the muscle coat in the rat jejunum was studied by histochemical methods. The lymphatic regrowth occurred behind the regeneration of blood vessels. Enzyme histochemistry for 5 -nucleotidase (5-Nase) demonstrated the manner of lymphatic regrowth, which was essentially attributed to vascular sprouting from preexisting lymphatics, and structural changes of the endothelial cells indicating their high migratory potential. The lymphatic regeneration progressively advanced with vascular maturation throughout the experimental period. The expression of 5-Nase in the regenerating lymphatics was increased in proportion to their growth. VEGF-C, a highly specific lymphangiogenic factor, was highly expressed in a subpopulation of interstitial cells, being close to the regrowing lymphatics with immunoreactivity of its receptor, VEGFR-3, in the regenerative area. The present findings suggest that transection of the intestinal muscle coat affords a useful experimental model for the investigation of lymphatic regeneration in tissue repair and that the interstitium may play a crucial role in lymphangiogenesis. |
