A Phosphodiesterase Type-5 (PDE-5) Inhibitor, Sildenafil, Ameliorates the NEC Induced Inflammation

The connection between intestine microbiota and lung disease is described as the gut-lung axis, these organ systems are somehow interrelated in both homeostasis and disease development. In newborns, the most important gastrointestinal complications are necrotizing enterocolitis (NEC), and the pulmonary complication both cause significant systemic morbidity. In this study, sildenafil administered at varying doses in neonatal rat model of experimental necrotizing enterocolitis and focused on both mRNA expression and histopathological alterations. 15-day-old Wistar Albino rat pups were randomly divided into six groups; Control, NEC, DMSO, Sil_1mg, Sil_5mg, Sil_10mg (n = 5). NEC induction was performed using hypoxia/asphyxia and cold stress. At the end of the experiment, lung tissues were harvested, molecular and histopathological alterations were analysed. Histopathological examination was performed with hematoxylin&eosin and masson trichrome staining in lung samples of neonatal rats and the mRNA expression levels of TNF-alpha, IL-6 and HSPa5 genes were analyzed. The mRNA expression levels of TNF-alpha, IL-6 and HSPa5 were increased in the NEC group compared to the control group and sildenafil treatment could significantly reduced the levels of the genes and inflammation (*p < 0.05 and **p <= 0.0001). Alveolar edema and hemorrhage findings were observed in the lung tissue of the NEC group. Interstitial edema and hemorrhage findings were reduced in the groups treated with sildenafil compared to the NEC group. The data we obtained indicate that sildenafil administering at different doses has therapeutic effect on NEC induced lung tissue inflammation both at the mRNA expression and tissue levels.