Acute effect of tetrandrine pulmonary targeting microspheres on hypoxic pulmon ary hypertension in rats

Objective To assess the effect of tetrandrine (Tet) pulmonary targeting microspheres on hy poxic pulmonary hypertension and evaluate its selective action on pulmonary circ ulation.Methods Twenty rats were exposed to hypoxic conditions for 3 weeks. Ten rats were used as normoxic controls. We administered Tet pulmonary targeting microspheres to 1 0 hypoxic rats and Tet aqueous solution to 10 hypoxic rats and the 10 control ra ts. Mean pulmonary arterial pressure (mPAP) was measured by a right cardiac cat heterization, and mean systemic blood pressure (mSBP) was measured by left femor al catheterization. Results Rats exposed to hypoxia developed pulmonary hypertension. The decrease in mPAP in rats treated with Tet pulmonary targeting microspheres was significantly grea ter than that in rats receiving Tet aqueous solution (P<0.05), and the effe cts were longer with Tet pulmonary targeting microspheres. Moreover, Tet pulmon ary targeting microspheres, unlike Tet aqueous solution, did not decrease mSBP. Conclusion Tet pulmonary targeting microspheres were more effective than Tet aqueous soluti on in treating hypoxic pulmonary hypertension and acted selectively on the pulmo nary circulation.