Evaluation of the therapeutic effects of oestradiol on the systemic inflammatory response and on lung injury caused by the occlusion of the proximal descending aorta in male rats.

OBJECTIVES: Ischaemia and reperfusion-induced microvascular dysfunction is a serious problem encountered during a variety surgical procedures, leading to systemic inflammation and affecting remote organs, specially the lungs. 17ß-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17ß-oestradiol therapeutic effects after aortic ischaemia and reperfusion (I/R) by evaluating lung inflammation. METHODS: Twenty-four Wistar rats were submitted to I/R by insufflation of a 2-F catheter in thoracic aorta for 20 min. Reperfusion took 4 h and 17ß-oestradiol (280 µg/kg, i.v.) was administered after 1 h of reperfusion. Sham-operated rats were controls. Bronchoalveolar lavage was performed and lung samples were prepared for histopathological analysis and tissue culture (explant). Interleukin (IL)-1ß, IL-10 and tumour necrosis factor-α were quantified. RESULTS: After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17ß-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17ß-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1ß increased after I/R and 17ß-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1ß and IL-10 in lung explants, reduced by 17ß-oestradiol. CONCLUSIONS: Our results showed that 17ß-oestradiol treatment performed in the period of reperfusion, modulated the systemic response and the lung repercussions of I/R by thoracic aortic occlusion. Thus, we can suggest that 17ß-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.

Modulatory effects of 17ß-estradiol on acute lung inflammation after total occlusion of the descending aorta in male rats.

As a consequence of systemic inflammation caused by ischemia and reperfusion (I/R) due to aortic occlusion, the lungs can exhibit increased microvascular permeability, local release of pro-inflammatory mediators, and leukocyte infiltration. Lung tissue infiltration by activated neutrophils is followed by acute respiratory distress syndrome, which is linked to acute pulmonary microvascular damage, high mortality rates, and organ dysfunction. Previous studies have demonstrated that female sex hormones modulate the inflammatory response and that prophylactic treatment with 17ß-estradiol (E2) can prevent fatalities and preserve mesenteric perfusion and intestinal integrity after ischemia/reperfusion induced by aortic occlusion. In this study, we focused on the protective effects of estradiol after aortic ischemia/reperfusion by evaluating lung injury and endothelial alterations. Upon anesthesia and mechanical ventilation, male rats were subjected to aortic occlusion for 20 min, followed by 2 h of reperfusion. In parallel, one group of rats received a single injection of estradiol (280 µg/kg, i.v.) 30 min before ischemia. We observed increased serum concentrations of IL-1ß, IL-6 and IL-10 in the I/R rats and E2 was able to reduce them. E2 effects after 2 h of reperfusion resulted mainly in decreasing of edema, iNOS expression and preventing leukocyte infiltration. Overall, our data indicate that estradiol might be a supplementary approach to deal with systemic processes and lung deterioration.

Protective effects of 17ß-oestradiol on coagulation and systemic inflammation after total occlusion of the descending aorta in male rats.

OBJECTIVES: The surgical treatment for diseases of the descending aorta is related to a high mortality rate because of the activation of a systemic inflammatory process due to ischaemia and reperfusion (I/R) injury. Activation of coagulation can contribute to the inflammatory process, resulting in microcirculatory damage and multiple organ failure. Our goal was to evaluate the role of prophylactic intravenous 17ß-oestradiol (E2) in coagulation, the inflammatory response and hepatic injury after occlusion of the descendent proximal aorta in male rats. METHODS: Wistar male rats were randomized and allocated to 3 groups (n = 8 per group): sham, surgically manipulated; IR, animals subjected to I/R; and E2, animals treated with E2 (280 µg/kg, intravenously) before I/R. I/R was induced by insertion of a 2-Fr Fogarty arterial embolectomy catheter in the descending aorta, which was occluded for 20 min, followed by a reperfusion period of 2 h. Serological markers, platelet aggregation, hepatic vascular flow, systemic and liver inflammatory response and apoptosis were analysed. The coagulation process was evaluated by thromboelastometry. RESULTS: The aortic occlusion led to a reduction in plasma fibrinogen concentration in parallel with increased clotting time, greater clot firmness and reduced lysis. E2 treatment was able to increase fibrinogen, prevent the increase in clotting time and normalize clot firmness, but it exerted only a mild effect on clot lysis. Platelet aggregation was increased by IR, and E2 treatment was able to reduce it. There was a reduction in flow percentage in the IR group that was not prevented by E2. In parallel, higher aggregate formation was observed in the vessels of the IR group of animals. There was increased systemic release of interleukin-1-ß, interleukin-6 and interleukin-10 in the IR group, which was reduced in the treated animals. CONCLUSIONS: The current results suggest that pretreatment with E2 before an ischaemic period induced by occlusion of the proximal descending aorta is effective in preventing alterations in coagulation and systemic inflammation due to I/R injury.

17ß-Estradiol Treatment Protects Lungs Against Brain Death Effects in Female Rat Donor.

BACKGROUND: Brain death (BD) affects the viability of lungs for transplantation. A correlation exists between high-lung inflammation after BD and the decrease in female sex hormones, especially estradiol. Therefore, we investigated the effects of 17ß-estradiol (E2) treatment on the lungs of female brain dead rats. METHODS: Female Wistar rats were divided into 4 groups: BD (submitted to BD for 6 h), sham (false operated), E2-T0 (treated with E2 immediately after BD; 50 µg/mL, 2 mL/h), and E2-T3 (treated with E2 after 3 h of BD; 50 µg/mL, 2 mL/h). Lung edema, hemorrhage, and leukocyte infiltration were analyzed. Adhesion molecules were evaluated, and analysis of NO synthase gene and protein expression was performed using real-time PCR and immunohistochemistry, respectively. Release of chemokines and matrix degradation in the lungs was analyzed. RESULTS: BD increased leukocyte infiltration, as shown by intravital microscopy (P = 0.017), bronchoalveolar lavage cell count (P = 0.016), the release of inflammatory mediators (P = 0.02), and expression of adhesion molecules. BD also increased microvascular permeability and the expression and activity of matrix metalloproteinase-9 in the lungs. E2 treatment reduced leukocyte infiltration, especially in the E2-T3 group, release of inflammatory mediators, adhesion molecules, and matrix metalloproteinase activity in the lungs. CONCLUSIONS: E2 treatment was successful in controlling the lung inflammatory response in females submitted to BD. Our results suggest that E2 directly decreases the release of chemokines, restraining cell traffic into the lungs. Thus, E2 has a therapeutic potential, and its role in improving donor lung quality should be explored further.

Treatment with 17ß-estradiol protects donor heart against brain death effects in female rat.

The viability of donor organs is reduced by hemodynamic and immunologic alterations caused by brain death (BD). Female rats show higher heart inflammation associated with the reduction in female sex hormones after BD. This study investigated the effect of 17ß-estradiol (E2) on BD-induced cardiac damage in female rats. Groups of female Wistar rats were assigned: Sham-operation (Sham), brain death (BD), treatment with E2 (50 µg/ml, 2 ml/h) 3 h after BD (E2-T3), or immediately after BD confirmation (E2-T0). White blood cell (WBC) count was analyzed; cytokines and troponin-I were quantified. Heart histopathological changes and expression of endothelial nitric oxide synthase, endothelin-1, intercellular adhesion molecule-1, BCL-2, and caspase-3 were evaluated. Cardiac function was continuously assessed for 6 h by left ventricular pressure-volume loop analysis. E2 decreased the BD-induced median serum concentration of troponin-I (BD:864.2 vs. E2-T0:401.4; P = 0.009), increased BCL-2 (BD:0.086 vs. E2-T0:0.158; P = 0.0278) and eNOS median expression in the cardiac tissue (BD:0.001 vs. E2-T0:0.03 and E2-T3:0.0175; P < 0.0001), and decreased caspase-3 (BD:0.025 vs. E2-T0:0.006 and E2-T3:0.019; P = 0.006), WBC counts, leukocyte infiltration, and hemorrhage. 17ß-estradiol treatment was effective in reducing cardiac tissue damage in brain-dead female rats owing to its ability to reduce leukocyte infiltration and prevent cardiomyocyte apoptosis.