Urotensin â…¡ Receptor Mediates The Expression Of Interleukin-6 In Rat Adventitial Fibroblasts Stimulated By Homocysteine

BackgrounBackgroundHyperhomocysteinemia is a pathological condition characterized by elevation of plasmahomocysteine. Hyperhomocysteinemia is an independent risk factor for atherosclerotic diseaseand other vascular diseases. The mechanisms by which homocysteine contributes toatherosclerotic vascular disease remain poorly understood. Many of the major diseases,including cardiovascular disease, such as atherosclerosis, cardiac hypertrophy and heart failure,are widely recognized as inflammatory diseases. Many reports indicated that adventitialfibroblasts may be an early event with a significant role during the development of vascularinflammatory diseases. Interleukin-6(IL-6)plays a critical role in the development ofcardiovascular diseases, and many studies have proved that IL-6 were promoted inhyperhomocysteinemia, however, its mechanisms of Hcy on the expression of IL-6 in rat aorticadventitial fibroblasts have not been elucidated clearly. Our previous study showed that bothurotensin II (urotensin II, UII) and its receptor UT expression in aorta were increased inhyperhomocysteinemic rats. UII has been demonstrated to be involved in vascular remodeling.It is necessary to explore the relationship between UII /UT system and IL-6 in homocysteineeffects.ObjectiveTo investigate the mechanisms of Hcy on IL-6 expression in rat aortic adventitial fibroblasts,and explore whether urotensin II receptor UT and Rho protein kinase inhibitor Y27632 areinvolved in the process. To investigate whether Hcy has direct effect on the expression of IL-6.Methods①Adventitial fibroblasts isolated from aorta of adult Sprague-Dawley rats were prepared bythe explant culture method. The cells were pretreated by UII receptor antagonist SB710411(10-6mol/l) and Rho protein kinase inhibitor Y27632(10-5mol/l) for 30 min, then incubated with 100μmol/L Hcy for 6h. thereafter, the IL-6 expression were evaluated by RT-PCR.②Incultured adventitial fibroblasts isolated from aorta of adult Sprague-Dawley rats,Growth-arrested adventitial fibroblasts were incubated in serum-free medium withHcy(100μmol/L)for different time(0h, 2h, 4 h, 6h, 8h, 12h, 24h).Then RT-PCR was used todetect the expression of UT.ResultResults1. Hcy could promote IL-6 expression in the adventitial fibroblasts. The effects of Hcy couldbe inhibited by the UII receptor antagonist SB710411(10-6mol/l) and the Rho protein kinaseinhibitor Y27632(10-5mol/l) (P<0.01).2. Hcy induced GPR14 expression in time-dependent manner, with maximal effect at 6 h(P<0.01).Conclusion1. The effects which Hcy promotes IL-6 can be inhibited by UII receptor antagonist SB710411and Rho protein kinase inhibitor Y27632.2. Hcy induced urotensin II receptor expression in time-dependent manner.3. The effects indicating that urotensin II receptor and Rho kinase might mediate the Hcy -induced IL-6 expression in rat adventitial fibroblasts.