Efeito protetor do óleo essencial de Cymbopogon citratus na injúria de células renais induzidas por isquemia e reperfusão: estudo in vitro e in silico

Abstract

Renal injury due to ischemia and reperfusion (I / R) is one of the main causes of acute kidney injury (AKI) with progression related to oxidative damage, inflammation and cell death, mainly of tubular cells. Different signaling pathways are involved in this process, such as the Ras / Raf1 / ERK and Nrf2-Keap1 transcription pathways. Several antioxidant strategies have been studied in order to prevent or minimize the damage caused by I / R. The essential oil of Cymbopogon citratus has citral as its major component, formed by geometric isomers: trans-geranial and cis-neral. These are described as having anti-inflammatory, antioxidant and potential to modulate the aforementioned transcription pathways. The objective of this study was to evaluate the cytoprotective effect of Cymbopogon citratus essential oil on proximal tubular cells of the LCC-MK2 lineage in an in vitro I / R model, in addition to investigating the interaction of citral isomers, major components of oil, in cell signaling pathways. The cells were exposed to a medium deprived of glucose, pyruvate and fetal bovine serum and subjected to 24 hours of hypoxia, using an anaerobic chamber. Then, reoxygenation and supplementation of the culture medium was performed, followed by treatment with essential oil for another 24 hours. Cell viability was assessed by the 3- (4,5-Dimethylthiazol-2-yl) -2,5-diphenyltetrazolium (MTT) reduction assay. Flow cytometry techniques were used to evaluate the mechanism of cell death, intracellular ROS production and change in mitochondrial transmembrane potential. A marker of renal damage to proximal tubular cells, the renal injury-1 molecule (KIM-1), was determined from the cell supernatant. Ultrastructural changes were analyzed by scanning electron microscopy (SEM). The analysis of the silica models of the citral isomers were performed by molecular docking and pharmacokinetic prediction tools. The results showed a cytoprotective effect of Cymbopogon citratus essential oil by increasing cell viability, reducing intracellular ROS and restoring mitochondrial transmembrane potential after ischemia and reoxygenation. The treatment at a concentration of 125 μg/ml decreased the release of KIM-1 and attenuated the ultrastructural damage caused by I / R. Citral isomers have a greater affinity for the Raf1 protein than for Keap1, with a greater number of hydrophobic bonds and free binding energy. Pharmacokinetic studies did not reveal differences between isomers.