Influence Of Urotensin Ⅱ On Proliferation And Collagen Synthesis In Cultured Cardiac Fibroblasts

Objective: human Urotensin II (hU2) is known to be the most potent endogenous human vasoconstrictor. hUII and its receptor, orphan G protein-coupled receptor-14 (GPR14), diffusely express in cardiovascular system. It is proposed that hUII could be another type of neuroendocrine regulator that takes part in the development of cardiovascular disease. To provide laboratory evidences, this work has designed to observe the impact of hU II on the collagen synthesis and cardiac fibroblasts (CFs) proliferation in cultured CFs of neonatal Sprague-Dawley (SD) rat origin. Whether urotensin II had acted as a neuroendocrine mediator through non-hemodynamic manner on myocardial remodeling, a pathologic process that was seen in heart failure, were then discussed.Methods: CFs of neonatal SD rats were isolated by trypsin digestion method and growth-arrested CFs were stimulated by hU2 with varied concentrations. MTT assay was employed to measure CFs proliferation and determine the cell number, l3]H-proline incorporation was used to determine collagen synthesis and the expression of collagen type I mRNA was detected by RT-PCR.Results: (1) Highly enriched fibroblast cultures were obtained as measured by immunohistochemical staining, vimentin positive rate was >90%; (2) MTT assay results shown that accompanying with the increase of hU II concentration, OD570 of CFs increased at first then decreased. Those cells treated with 10'8 hU2mol/L or 10-9mol/L hU2, OD570 was significantly higher than that of the control(both P<0.01); (3)CoL-1 mRNA levels of the cells treated with 10~7mol/L, 10"8mol/L or 10"9 mol/L hU II were significantly higher than that of the control; (4)hU II promoted [3]H-proline incorporation rate in CFs in a concentration-dependent manner. [3]H-proline incorporation value of 10~7mol/L, 10"8mol/L and 10~9mol/L hU II group were higher than that of control group(all, P<0.01).Conclusions: hUIInot only directly induce the proliferation of CFs, but also stimulate H-proline incorporation and significantly increase the collagen type I mRNA expression, characterized in a concentration-dependent manner. From this work we proposed that hUII could be another potent activator causing cardiac fibrosis, independent of other hemodynamic regulators and, with other neuroendocrine mediators, hUII may jointly takes part in the development of myocardial remodeling.