Abstract: AIM: To investigate the therapeutic effect of chloride channel blocker tamoxifen on hypoxia pulmonary hypertension in rats.Methods: Sixty male Wistar rats were randomly divided intotherapeutic group (H/Q group), hypoxia group(H group), normal control group(C group).Mean pulmonary artery pressure(mPAP), the ratio of the weight of right ventricle to that of left ventricle plus septum[RV(LV+S)], and the ratio of the pulmonary arteriole wall area to that of vascular total area(WA/TA), were measured at 4, 7, 14, 21 days.Results: The mPAP began to increase from 7 days, and reached peak at 21 days in hypoxia group, however it is obviously lower in therapeutic group at same time.The ratio of RV/(LV+S) began to increase from 14 days, and reached peak at 21 days in hypoxia group, however it is obviously lower in therapeutic group at same time.The ratio of WA/TA at 21 days in hypoxia group was significantly higher than therapeutic group, respectively(P<0.05).The ratio of VA/TA at 21 days in hypoxia group was significantly lower than therapeutic group, respectively (P<0.05).Conclusion: The data suggested Tamoxifen could reduce hypoxia-induced increased pulmonary artery pressure, inhibit hypoxia-induced hypertrophic right ventricle and pulmonary small artery thickness.Tamoxifen may be used in the treatment of hypoxia induced pulmonary hypertension.

Key words: tamoxifen, hypoxia pulmonary hypertension, hypoxia