Alleviative effects of green tea polyphenols on cyclosporine A-induced inhibition of vasorelaxation / 中国组织工程研究

ABSTRACT

BACKGROUND: Vasorelaxation plays an important role In the occurrence of cyclosporine A (CsA)-induced nephrotoxlcity.OBJECTIVE: To observe the alleviative effects of green tea polyphenols (GTP) on CsA-induced inhibition of vasorelaxation and the underlying mechanisms.METHODS: Sprague-Dawley rats were randomly and evenly divided into four groups CsA, control, CsA + GTP, and GTP. After 5 weeks of drug treatment, blood urea nitrogen (BUN) and creatinine (Cre) levels were determined. Then the thoracic aorta rings were mounted on a bath system, and acetylcholine was used to induce vasorelaxation. The effects of L-NAME and indomethacin and the denuded vasorelaxation were evaluated.RESULTS AND CONCLUSION: The BUN and Cre levels in the CsA group were significantly higher than those in the control group (P < 0.05). The maximal response (Emax%) for acetylcholine-induced vasorelaxation in the CsA group was significantly lower than that in the control and GTP groups. After pretreatment with L-NAME, vasorelaxation was significantly lower in the CsA,CsA+GTP and GTP groups than in the control group. After pretreatment with indomethacin, vasorelaxation was significantly higher in the control, CsA +GTP, and GTP groups than in the CsA group. The level of nitric oxide metabolites in the vascular tissue in the CsA group was significantly lower compared with other groups. The results demonstrated that CsA can decrease nitric oxide levels in vascular tissues and induce abnormal endothelium-dependent vasorelaxation, which is mediated by nitric oxide pathway.