337.1: 17beta-Estradiol and Methylprednisolone Associated Treatment Modulates Early and Late Cytokine Release in Lungs From Female Rats Submitted to Brain Death

Abstract

Introduction: Brain death (BD) causes hemodinamic and immunological alterations that compromise organs quality and viability. Compared to other organs, lungs have the lowest usage rate due to increased vulnerability during retrieval. After BD, lungs from female donors transplanted to male recipients present worse prognostics in comparison to organs from males donors. This is correlated with a higher inflammatory response in females, associated with the acute reduction of female sex hormones. Also, glucocorticoids are hormones known to influence the inflammatory response and, in females, evidence suggests that the presence of both estradiol and glucocorticoids is important to secure an appropriate response to inflammation. The aim of this study is to evaluate the associated treatment of E2 and methylprednisolone (MP) in female rats after BD.= Methods: Female Wistar rats were used and BD was induced by fast inflation of an intracranial balloon catheter. The animals were maintained for 6h. Rats received MP (MP, 4 mg/ml i.v-2 ml/h) or MP and E2 (MP/E2, 50 ug/ml i.v-2 ml/h) after 3h of BD until the end of experiment. As controls, we used non-BD animals (sham-operated (S).) Lung samples were collected after 6h for tissue homogenate, explant (lung tissues kept in culture medium for 24h), and relative gene expression analyzes. IL-1β, IL-6, TNF-α and CINC-1 were quantified in homogenate and explant samples. In parallel, IL-1β, IL-6 and TNF-α gene expression was also evaluated. Results: In lung tissue homogenate, BD increased IL-6 after 6h and the two hormones associated treatment was able to reduce this cytokine (p=0.028). Both treatments were capable of reducing IL-1β (p=0.005). There were no differences among groups in CINC-1 and TNFα concentrations. In lung culture, MP/E2 treatment reduced IL1β (p=0.029) and CINC1 (p=0.007) and both treatments reduced IL-6 (p=0.002). As also observed in homogenate samples, there was no difference in explant TNFα levels. Moreover, lung relative gene expression of IL-1β was reduced by both treatments (p=0.020). Despite being increased after BD, TNFα gene was not altered by the treatments and no differences were observed in IL-6 gene expression. Conclusion: These data suggests that the associated administration of E2 and MP after BD has anti-inflammatory effects by reducing the release and expression of cytokines and chemokines, especially IL-1β, IL-6 and CINC1, right after BD and 24h hours later, as seen in the explant analyzes. These results suggest that, in females, the association of corticoids and estrogens is a potential therapy option to improve organ quality. This study was financed by 2020