Effects of Beet Juice Supplementation on Monocrotaline-Induced Pulmonary Hypertension in Rats.

BACKGROUND Recently, attention has been focused on the cardiovascular protective effects of beet juice (BJ) with high amounts of nitrate. In this study, we examined the effect of BJ supplementation in a rat model of monocrotaline (MCT)-induced pulmonary hypertension (PH). METHODS MCT (60 mg/kg) was subcutaneously administered to rats, and BJ (prepared by dissolving BJ powder at a concentration of 1 g/l or 10 g/l in drinking water) supplementation was started from the day of, 1 week before, and 2 weeks after MCT injection. Saline-injected rats given drinking water were used as controls. RESULTS Low-dose BJ supplementation starting from the day of MCT injection exerted protective effects on the MCT-induced elevation of right ventricular systolic pressure, right ventricular hypertrophy, and pulmonary arterial remodeling, without causing a significant increase in plasma nitrite plus nitrate (NOx) levels. On the other hand, such beneficial effects were not observed with high-dose BJ supplementation, although the NOx levels were slightly higher than those in the low-dose group. In addition, low-dose BJ supplementation starting from 1 week before MCT injection did not improve PH symptoms, as described above. Furthermore, low-dose BJ supplementation starting from 2 weeks after MCT injection was ineffective against functional and morphological alterations in pulmonary circulation associated with MCT-induced PH. CONCLUSIONS Habitual ingestion of a suitable amount of BJ could be a potential option for preventing PH. However, beneficial effects cannot be expected when PH has developed to some degree.