Neural crest cell migration in relation to extracellular matrix organization in the embryonic axolotl trunk

Temporal and regional aspects of early neural crest cell migration in relation to extracellular matrix (ECM) organization and distribution in the embryonic axolotl trunk were studied by light microscopy, TEM, and SEM. The dominating structure of the interstitial ECM is a complex network of fibrils, which are indicated by ruthenium red staining to consist of collagen in association with ruthenium red-positive components, probably including glycosaminoglycans. The ECM fibrils, which are largely used as substratum for locomotion by the crest cells, have a temporally and regionally specific organization and distribution. Increase in ECM fibrils on the neural tube, ahead of the crest cell front, is correlated with initiation of crest cell emigration, and it is suggested that the fibrils may stimulate this process by providing a suitable substratum for cell locomotion. An increase in ECM fibrils in extracellular spaces surrounding the crest cell population is correlated with an expansion of these spaces and with progressing crest cell migration into them. It is proposed that the spatial organization of the ECM fibrils influences crest cell shape and orientation during early migration.