Expression of Urotensin II and its receptor on right ventricle in rats of pulmonary hypertension / 中国应用生理学杂志

ABSTRACT

<p><b>AIM</b>To observe the expression of Urotensin II (U II) and its receptor (UT) on right ventricle in rats with chronic pulmonary hypertension induced by hypoxia and hypercapnia.</p><p><b>METHODS</b>Twenty male SD rats were randomly divided into normal control group (NC) and hypoxia-hypercapnia 4-week group(HH). Mean pulmonary arterial pressure(MPAP) and the weight ratio of right ventricle (RV) to left ventricle plus septum (LV+ S) were calculated separately. U II in plasma was measured using radioimmunoassay. The expression of U II was observed in right ventricle myocytes and right ventricle arteries by immunohistochemistry. The expression of U II mRNA and UT mRNA were observed in right ventricle myocytes and right ventricle arteries by in situ hybridization.</p><p><b>RESULTS</b>(1) The MPAP and RV/LV + S of HH group were higher respectively than those of NC group (P < 0.01, respectively). (2) The plasma U II content of HH group did not increased obviously than that of NC group. (3) The expression score of U II, U II mRNA, UT mRNA by right ventricle myocytes in HH group were higher significantly than those of NC group (P < 0.01 respectively). (4) The average value of integral light density (LD) of U II, U II mRNA, UT mRNA by right cardial arteries in HH group were higher significantly than those of NC group (P < 0.01, respectively).</p><p><b>CONCLUSION</b>The expression of U II in right ventricle arteries and right ventricle myocytes increase significantly during the formation of pulmonary hypertension and right ventricle hypertrophy in rats chronically exposed to hypoxia-hypercapnia. These changes indicate that U II might be involved in right ventricle remodeling, which promotes proliferation of cardiac muscle cells.</p>