The role of urotensin-II and its receptors in sepsis-induced lung injury under diabetic conditions.

This study aimed to investigate the potential role of urotensin-II receptors in sepsis-induced lung injury in diabetic mice using urotensin-II receptor agonists and antagonists. A total of 110 male CD1 mice were used in this study. Diabetes was induced by 200mg/kg streptozotocin. One month after diabetes induction, the cecal ligation and puncture-induced polymicrobial sepsis model was applied in the diabetic and non-diabetic mice. Low and high doses of human urotensin-II agonist (HU-II) and antagonist (palosuran) were administered one hour after sepsis induction. HU-II administration was repeated in two-hour intervals. Blood and tissue samples were collected at 6 and 12H after sepsis induction for biochemical, molecular, and histopathologic examinations. Regarding to the lungs mRNA expression and immunohistochemistry results of TNF-α, IL1 β, IL6, and NF-κB, it was observed that cytokine levels significantly increased in the diabetes group and the sepsis groups compared to the healthy group; this increase was significantly higher in the diabetes-sepsis groups. Our biochemical (superoxide dismutase, glutathione, and malondialdehyde) and histopathological findings in the lungs also supported these results. All increased parameters were significantly reduced dose-dependently by the administration of palosuran, an urotensin receptor antagonist. mRNA expression of urotensin-II and its receptor were examined in the lung tissue. Palosuran administration significantly reduced the urotensin-II and urotensin-II receptor levels that increased in the damaged tissue. This study has shown that urotensin-II and urotensin-II receptors contribute to the aggravation of sepsis-induced lung injury in diabetic mice; palosuran prevents this damage by antagonizing urotensin-II receptors.