Alterations Of Urotensin â…¡ And Its Receptor In Rats With Vascular Calcification

Objective: To observe the expression of the Urotensin II (UII) and its receptor (UT) in vivo in vascular calcification and to explore the significance of UII/UT system in vascular calcification.Method: 9-week-old male SD rats were randomly divided into four groups: control group, vascular calcification group [Vitamin D3 (300,000U/kg) IM and Nicotine (25mg/kg) intragastric administration twice in the first day, and then fed for four weeks], vascular calcification + L-Arg (1g/kg, intragastric administration for four weeks, one time one day) group and vascular calcification + Met (1g/kg, intragastric administration for four weeks, one time one day) group. One group had 10 rats. Four weeks later, we were going to assay. The extent of calcification was estimated by assaying calcium content, alkaline phosphatase (ALP) activity were detected and Von Konsa staining was used to detect the deposit of calcium in aorta. The content of UII protein in plasma and cardiovascular tissues were determined by radioimmunoassay (RIA), and the protein of UII in rat aorta was observed by the immuno-histochemistry staining. The UT mRNA amount was determined by using RT-PCR. All data was analysed by Prism 4.Result: Von Kossa staining for calcification, showed positive staining as black areas within in the main, large, nodular structures, was been shown in Vascular Media. Compared to control group, calcium content in vascular tissues was increased by 2.2 folds (P<0.01) in vascular calcification group, 1.8 folds (P<0.05) in vascular calcification + L-Arg group and 6.9 folds (P<0.01) in vascular calcification + met group. Compared to control group, ALP activity in vascular tissues was increased by 1.7 folds (P<0.05) in vascular calcification group, but there were no significant differences among the other three groups. Compared to control group, the content of UII protein was increased in vascular by 3.0 folds in vascular calcification group, 2.6 folds in vascular calcification + L-Arg group and 2.9 folds in vascular calcification + met group (P<0.05), and immuno-histochemistry staining showed that the UII expression was increased in this three groups too, but it had no significant differences in plasma in four groups. The gene expression of UT was up-regulated in vascular and myocardium by 1.8 folds, 1.9 folds (P<0.05) in vascular calcification group, 1.5 folds, 1.3 folds (P>0.05) in vascular calcification + L-Arg group and 2.7 folds, 2.2 folds (P<0.05) in vascular calcification + met group as compared to control group.Conclusion: The expression of UII/UT system is increased in calcification cardiovascular tissues, suggesting that UII/UT system plays a role in the pathogenesis of vascular calcification.