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Preventive and therapeutic effects of nitrendipine on hypoxic right ventricular hypertrophy
1Institute of High Altitude Medicine, Third Military Medical College, Chongqing, China.
Aim:
To assess whether nitrendipine (Nit) can be used to prevent and treat the hypoxic right ventricular hypertrophy (RVH).
Methods:
Rats were exposed to a simulated altitude of 5000 m (barometric pressure = 54 kPa) for 30-60 d. Nit (10-20 mg.kg-1.d-1) was administered via gavage. The therapeutic efficacy was evaluated with right ventricular weight index (RVWI), right ventricular systolic pressure (RVSP), and myocardial ultrastructure.
Results:
Chronic intermittent hypoxia for 30 d (8 h.d-1) resulted in an increase of RVSP and RVWI as well as in the changes of RV myocardial ultrastructure. As the hypoxic time was prolonged to 60 d, RVWI and RVSP were not further augmented. Nit (20 mg.kg-1.d-1, i.g.), when administered from the beginning of hypoxia, reduced RVSP (8.1 +/- 1.1 vs 6.0 +/- 1.0 kPa, P < 0.05) and RVWI (1.014 +/- 0.012 vs 0.915 +/- 0.049 mg/g body weight, P < 0.05). After development of hypoxic RVH, Nit (20 mg.kg-1) also decreased RVSP (7.9 +/- 1.0 vs 6.2 +/- 0.8 kPa, P < 0.05) and RVWI (1.02 +/- 0.13 vs 0.88 +/- 0.12 g/kg body weight, P < 0.05). Myocardial blood flow was increased and myocardial ultrastructure became nearly normal in rats treated with Nit.
Conclusion:
Nit prevented and lessened the hypoxic right ventricular hypertrophy.