Collagenase inhibitor stimulates cleft formation during early morphogenesis of mouse salivary gland.

A collagenase inhibitor obtained from the culture medium of bovine dental pulp markedly enhanced the cleft formation of mouse embryonic salivary gland epithelium when the inhibitor was included in the culture medium for 12-day and 13-day salivary glands. Determination of collagenase activity using [3H]collagen as substrate indicated that there was a latent collagenase activity in 12-day glands. In addition, a highly purified Clostridial collagenase freed from protease and hyaluronidase activities, strongly inhibited initiation of the cleft formation of the 12-day epithelium. Scanning electron microscopic observation showed that abundant collagen-like fibrils were seen on the epithelium in the collagenase-inhibitor-treated glands compared to those in the control. These findings suggest that during early morphogenesis tissue collagenase may regulate the cleft formation in the epithelium.