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. 17β-Oestradiol reduces pulmonary repercussions from various acute lung injury forms. Here, we focused on the 17β-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 17β-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)-1β, IL-10 and tumour necrosis factor-α were quantified.

Results: After I/R, higher number of leukocytes in bronchoalveolar lavage were reduced by 17β-oestradiol. The treatment also decreased leukocytes in lung tissue. I/R increased lung myeloperoxidase expression, with reduction by 17β-oestradiol. Serum cytokine-induced neutrophil chemoattractant 1 and IL-1β increased after I/R and 17β-oestradiol decreased cytokine-induced neutrophil chemoattractant 1. I/R increased IL-1β and IL-10 in lung explants, reduced by 17β-oestradiol.

Conclusions: Our results showed that 17β-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 17β-oestradiol might be a supplementary approach leading the lung deterioration after aortic clamping in surgical procedures.