Key Points
- To determine whether long-term administration of nifedipine or nisoldipine alters cardiac myocyte structural remodelling and attenuates reparative and reactive myocardial fibrosis in essential hypertension.
- Male spontaneously hypertensive rats (5.5 months old) and Wistar Kyoto control rats received 1000 ppm nifedipine, 1000 ppm nisoldipine, or no treatment for 22 weeks.
- Ventricular myocytes were isolated via retrograde coronary collagenase perfusion to measure cell volume, cell length, cross-sectional area, and total myocyte count.
- Picrosirius red staining of perfusion-fixed myocardium was used to quantify microscopic scarring (reparative fibrosis) as well as interstitial and perivascular (reactive) fibrosis.
- Nifedipine and nisoldipine significantly reduced systolic and diastolic blood pressure and significantly decreased left ventricular weight relative to body weight in spontaneously hypertensive rats, though values remained higher than normotensive controls.
- Microscopic scarring was significantly reduced and reactive interstitial and perivascular fibrosis were substantially decreased following treatment with either drug.
- Cardiac myocyte volume exhibited a slight, non-significant decrease with blood pressure attenuation, and total myocyte counts remained similar across all groups.
Structured PICO
Does nifedipine or nisoldipine prevent structural remodelling and myocardial fibrosis in spontaneously hypertensive rats?
PPopulationFive and a half month old male spontaneously hypertensive rats and Wistar Kyoto (WKY) rats
IIntervention1000 ppm nifedipine or nisoldipine for 22 weeks
CComparatorNo treatment (controls)
OOutcomeStructural remodelling of cardiac myocytes and reparative and reactive myocardial fibrosissurrogate
In a rat model of essential hypertension, long-term treatment with nifedipine or nisoldipine attenuates hypertension, decreases left ventricular mass, and reduces myocardial fibrosis.