Changes in the distribution of fibronectin and collagen during development of the neonatal rat heart

Specific antibodies to different types of collagen (I, III, IV and V) and fibronectin were used to investigate the formation of the collagenous connective tissue network in the neonatal rat heart. Immunofluorescence data showed that the staining pattern for fibronectin and Type III collagen was similar as were the patterns for Type I, IV and V collagens. These differences in the staining patterns correlated with previous studies on the development of the connective tissue network and indicated that Type III collagen was the major type of collagen associated with the myocytes. The results of this study showed that by 20 days post-partum the development of the connective tissue network was similar to the adult.