Abstract
We designed experiments to determine whether intermittent hypoxia would produce significant pathologic and physiologic changes in rats and whether pretreatment with a calcium channel blocker, nitrendipine, would reduce the pulmonary vascular remodeling and right ventricular hypertrophy caused by intermittent hypoxia. Intermittent exposures to hypobaric hypoxia (0.5 atmospheres) 10 h a day for 30 days increased the hematocrit (65 ± 1 versus 42 ± 1%, mean ± SEM), right ventricular systolic pressure (33 ± 1 versus 20 ± 1 mmHg), and right ventricular weight adjusted for body weight (RV/BW) (126 ± 6 versus 60 ± 2 mg/100 g) in male Sprague-Dawley rats. Intermittent hypoxia also increased the percentage of small pulmonary vessels with muscle (76 ± 3 versus 19 ± 5%) and the thickness of the vessel wall as a percentage of the total vessel diameter (34 ± 1 versus 22 ± 1%). Nitrendipine (10 mg/kg) prevented the acute increase in right ventricular systolic pressure caused by hypoxia. Chronic treatment with nitrendipine (10 mg/kg given twice a day by gavage for 30 days) significantly reduced the increase in hematocrit (61 ± 1 versus 65 ± 1%), right ventricular systolic pressure (29 ± 1 versus 33 ± 1 mmHg), and RV/BW (108 ± 4 versus 126 ± 6 mg/100 g) caused by hypoxia. Chronic treatment with nitrendipine also reduced the percentage of small pulmonary vessels with muscle (38 ± 8 versus 76 ± 3%) and prevented the increase in vessel wall thickness (20 ± 2 versus 34 ± 1%). Thus, nitrendipine treatment significantly reduces the right ventricular hypertrophy and pulmonary vascular changes caused by intermittent hypoxia.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 375-379 |
| Number of pages | 5 |
| Journal | American Review of Respiratory Disease |
| Volume | 133 |
| Issue number | 3 |
| State | Published - Jun 11 1986 |
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine