The Role of Estradiol in Pulmonary Hemodynamics during Ventilation with Hypoxic Gas in Female Rats Subjected to Cirrhosis

Liver diseases may lead to a wide spectrum of pulmonary disorders with a high incidence in women. The aim of this study was to evaluate the effect of liver damage and ovariectomy with or without estradiol on pulmonary hemodynamics during ventilation of animals with normoxia and hypoxia gas. Forty Sprague Dawley female rats were randomly divided into four groups of ovariectomy (OVX); ovariectomy with a daily injection of sesame oil, a solvent of estradiol (OVX+Oil); bile duct ligation with ovariectomy (CBDL+OVX) and associated with estradiol (CBDL+OVX+E2). After 28 days of the first surgery, animals were anesthetized. Tail blood samples were taken to measure liver enzymes, estradiol and NO metabolites. Animals were tracheostomized and femoral vessels were cannulated. Then, arterial pressure and right ventricular systolic pressure were recorded during mechanical ventilation with normoxic and hypoxia gas (10% oxygen). AST, AST/ALT ratio, direct and total bilirubins, and estradiol in the CBDL+OVX and CBDL+OVX+E2 groups were significantly higher than those in the OVX group, and they were higher in the CBDL+OVX+E2 group than those in the CBDL+OVX group. Ventilation of animals with hypoxia gas resulted in an increase in right ventricular systolic pressure (RVSP) only in the OVX group compared to its own base values. The plasma concentration of NO metabolites in the CBDL+OVX+E2 group was significantly higher than that in other groups. Estradiol worsen the liver disorders. Furthermore, pulmonary vascular response to hypoxia gas is disrupted in liver disorders, which may be partly linked to the effect of estradiol and NO productions.