DEVELOPMENTAL REGULATION OF COLLAGEN DIFFERENTIAL EXPRESSION IN THE RABBIT BLADDER

Purpose: It has been suggested that the amount and relative ratios of different types of collagen influence bladder compliance. To understan d the mechanisms regulating collagen synthesis and degradation in the bladder we investigated the gene expression of collagen types I and II I in the rabbit bladder during normal development. Materials and Metho ds: New Zealand white rabbits ages fetus to adult were used for this s tudy. The mid portion of the bladder wall was harvested. Northern blot hybridization was performed to analyze quantitatively collagen types I and III messenger (m) ribonucleic acid (RNA), and in situ hybridizat ion was done to localize the messages. Corresponding protein distribut ions were obtained by immunohistochemical staining. Results: Types I a nd III collagen are developmentally regulated at the level of gene exp ression. The temporal and spatial distribution of the mRNA transcripts of alpha 1(I) and alpha 1(III) correlates with extracellular protein deposition. Differential distribution of the mRNA transcripts is also developmentally regulated. Conclusions: This study characterizes the r elationship between collagen gene expression and normal rabbit bladder development. The expression of alpha 1(I) and alpha 1(III) alters as the bladder grows. High levels and nonconcordant up and down regulatio n of different types of collagen mRNA during early development demonst rate the complexity of the extracellular matrix in a young bladder. Th is observation may be important in our understanding of the injury res ponse in a developing versus mature bladder.