Objective:

The aim of current research was to determine whether male sex hormones play any role in development of pulmonary hypertension, induced by 1 week of hypoxic exposure.

Methods:

Twenty male Wistar rats were gonadectomized at the age of 4 weeks and twenty male rats were used as matched controls. 4 weeks after operation was performed the rats were divided into 4 experimental groups: 1) normoxic rats with intact testicles 2) normoxic gonadectomized rats 3) hypoxic rats with intact testicles 4) hypoxic gonadectomized rats. Animals designated for exposure to CH were housed in a hypobaric chamber at simulated altitude of 5,000 m, 10 h a day, 7 days. Age-matched normoxic control animals were housed at ambient air. After exposure to hypoxia pulmonary arteries remodeling, calculated as medial area to total vascular area (M/T) and right ventricular hypertrophy calculated as right ventricular to total heart weight ratio (RV/T) were measured as indices of PH. Systemic systolic blood pressure and serum level of testosterone and estrogen were also assessed.

Results:

After 7 days of chronic hypoxic exposure rats from groups 3 and 4 demonstrated significant right ventricular hypertrophy. In group 3 it was also associated with reduction of relative left ventricular weight (50.4±1% vs. 47.1±0,8%, p<0.05). Only rats from group 3 developed pulmonary vascular remodeling (0.37±0.01 vs. 0.47±0.01, p<0.05). Gonadectomized rats showed no significant changes in M/T compared to control (0.35±0.01 vs. 0.39±0.01, p>0.05). Systolic blood pressure and hormonal profile were unaffected by hypoxia in both groups.

Conclusions:

Androgen depletion reverses pulmonary vascular remodeling associated with hypoxic pulmonary hypertension in male rats.