Protective effect of apigenin in a rat model of lung ischemia-reperfusion

Objectives: Ischemia-reperfusion injury describes the sequence of pathological alterations occurring after cessation and reinstitution of blood circulation in a tissue. Lung Ischemia-Reperfusion Injury (LIRI) may result from trauma, pulmonary embolism, pulmonary thrombosis, and surgical procedures, such as lung transplantation and cardiopulmonary bypass during heart operations. The aim of our study was to examine the protective function of the flavonoid apigenin in a rat model of LIRI of the left lung.

Material and methods: For our purpose 32 male Wistar rats of 250-300g, were used and divided into eight groups: baseline and sham group, and 6 investigation groups with ischemia of either the left lung hilum or the left pulmonary artery. This includes 2 control groups without study medication (NaCl) and 2 groups each with one or two doses of apigenin intraperitoneally. In investigation animals thirty minutes of ischemia and 60 minutes of reperfusion were applied, whereas all vital parameters were continuously monitored. The animals were sacrificed at the end of reperfusion; the heart and both lungs were extracted and examined for morphological changes and blood samples were obtained. The phosphorylation of NF-κB was measured by Western-blot, as well as levels of IL-1β, Il-6, IL-10, iNOS and TNFα were analyzed.

Results: The Western-blot analysis revealed a markedly activation of NF-κB in the sham group and in the intervention group using NaCl, while the activation was suppressed in the apigenin-applicated groups. Levels of TNFα, iNOS and IL-6 also showed correlated values. The light microscopy confirmed the induction of tissue injury in both lungs in all but the baseline groups. The results suggest that the surgical procedure itself can induce a large damage to the lung tissue. The application of apigenin, especially in a single dose, had a beneficial effect confining the tissue damage.

Conclusion: The surgical procedure itself can induce a large damage to the lung tissue, with the effect being detrimental in both lungs. Administration in a single dose of apigenin can limit the ischemia-reperfusion damage.