Transforming growth factor β3 increases chondrocyte proliferation and decreases apoptosis in murine cricoid cartilage in vitro

OBJECTIVE: To determine if the luminal epithelium and/or exogenous transforming growth factor beta (TGF beta) affects growth of the cricoid. DESIGN: Subglottises from 20 neonatal mice were subdivided into four groups: A, five subglottises with luminal epithelium grown in basic medium; 13, five epithelium-free subglottises in basic medium; C, five epithelium-free subglottises in basic medium with supplemental TGF beta 1, and D, five epithelium-free subglottises in basic medium with supplemental TGF beta 3. RESULTS: Groups A and D demonstrated the greatest luminal area expansion. Group A rings demonstrated statistically higher chondrocyte proliferation than Groups B and C and lesser amounts of luminal apoptosis. Groups B and C rings demonstrated the least amount of cell proliferation, and greater luminal apoptosis relative to Group A. Groups A and D rings had similar apoptotic and proliferative results. CONCLUSIONS: Luminal epithelium exerts influence over the cricoid by increasing chondrocyte proliferation and decreasing the relative proportion of luminal chondrocytes that undergo apoptosis. Exogenous TGF beta 3, not TGF beta 1, also increases chondrocyte proliferation within the cricoid and appears to influence apoptosis as well. (C) 2008 American Academy of Otolaryngology-Head and Neck Surgery Foundation. All rights reserved.