ANGIOTENSIN-II AND BASIC FIBROBLAST GROWTH-FACTOR INDUCE NEONATAL BLADDER STROMAL CELL MITOGENESIS

Purpose: Our aims were to establish primary stromal cell cultures from the neonatal rabbit bladder and investigate the potential mitogenic e ffects of angiotensin II and basic fibroblast growth factor on these c ells. Materials and Methods: Primary bladder stromal cell cultures wer e obtained from 3-day-old rabbits, plated at a density of 3 x 10(4) ce lls per ml. and allowed to grow for 24 hours. Subconfluent cells were growth arrested in serum deficient (0.25% newborn calf serum) or serum -free media for 24 hours and then stimulated with 10(-7) M. angiotensi n II or 10 ng./ml. basic fibroblast growth factor for an additional 48 hours. Cell counts and [H-3] thymidine incorporation were done to mea sure cellular proliferation and deoxyribonucleic acid synthesis. Resul ts: Angiotensin II and basic fibroblast growth factor each stimulated neonatal bladder stromal cell proliferation and [H-3] thymidine incorp oration under serum deficient conditions. Angiotensin II provoked an a verage 26% increase in cell number (p <0.01) and 35% increase in [H-3] thymidine incorporation (p <0.01) compared to control values. Basic f ibroblast growth factor was an even more potent mitogen with a 47% inc rease in cell number (p <0.01) and 180% increase in [H-3] thymidine in corporation (p <0.01) compared to controls. In contrast, angiotensin I I and basic fibroblast growth factor each failed to have significant s timulatory effects under serum-free conditions. Conclusions: Angiotens in II and basic fibroblast growth factor induce a mitogenic response t o neonatal bladder stromal cells in vitro. These mitogenic effects req uire the presence of serum factors. Whether angiotensin II and basic f ibroblast growth factor are involved in the in vivo regulation of blad der growth associated with obstructive uropathy requires further inves tigation.