Platonin mitigates vascular hyporeactivity of thoracic aorta in septic rats

Background Vascular hyporeactivity contributes to hemodynamic alterations and circulatory failure in severe sepsis. Among the identified mechanisms, inflammation and oxidative stress are the most crucial ones in mediating the development of vascular hyporeactivity induced by sepsis. Platonin, a photosensitive dye and an antioxidant, possesses potent antiinflammation effects. We elucidated whether platonin could mitigate vascular hyporeactivity of thoracic aorta in septic rats. Material and methods Adult male Sprague–Dawley rats were randomized to receive sham operation (Sham), Sham plus platonin (100 μg/kg), cecal ligation and puncture (CLP), or CLP plus platonin (10, 50, or 100 μg/kg) and designated as the Sham, P, CLP, CLP + P(10), CLP + P(50), and CLP + P(100) group, respectively (n = 6 in each group). After maintaining for 12 hours, surviving rats were euthanized and thoracic aorta was isolated and vascular reactivity of aortic rings was determined. Results Vascular reactivity induced by vasoconstrictors phenylephrine and angiotensin II of the Sham and the P groups (n = 6 in both groups) were similar, whereas vascular reactivity of the CLP group (n = 5) were significantly lower than those of the Sham group (both P < 0.001). Of note, vascular reactivity induced by phenylephrine and angiotensin II of the CLP + P(10) group (n = 5) and the CLP group were not significantly different. In contrast, vascular reactivity induced by phenylephrine and angiotensin II of the CLP + P(50) and the CLP + P(100) groups (n = 6 in both groups) were significantly higher than those of the CLP group (phenylephrine: P = 0.024 and 0.017; angiotensin II: P = 0.031 and 0.036). Conclusion Platonin could mitigate vascular hyporeactivity of thoracic aorta in septic rats