Matrix formation in nasal septal cartilage of growing rats on a low calcium and vitamin D deficient diet.

Abstract

Rats in the late growing stage were fed for 14 days on a low calcium and vitamin D deficient diet which has previously been shown to cause altered craniofacial growth. The role of the nasal septal cartilage in this viscero-cranial growth aberration was evaluated by comparing the morphology and matrix formation of the nasal septal cartilage in the diet-deficient rats with that of normal rats. The morphology was assessed on dry skulls and the matrix formation by biochemical measurement of the incorporation of radioactive sulphate. Increased matrix formation, indicating an increased interstitial growth capacity, was found in all parts of the nasal septal cartilage in the diet-deficient rats, the antero-posterior length of the septal cartilage was decreased and the posterior height was increased compared with normal rats but the anterior height and the width of the cartilage were the same in diet-deficient and normal rats. The discrepancy between the interstitial growth and the morphology of the septal cartilage suggests that nasal septal cartilage morphology might be influenced by the surrounding skeletal tissues. It seems that the viscero-cranial growth in the diet-deficient rats was not exclusively influenced by nasal septal cartilage growth, supporting the view that the nasal septal cartilage has a subordinate role in midfacial growth.