Magnolol attenuates the lung injury in hypertonic saline treatment from mesenteric ischemia reperfusion through diminishing iNOS.

Background: Hypertonic saline (HTS) administration can decrease the inflammation following ischemia reperfusion. Magnolol is a potent antioxidant. The present study investigated whether combined treatment of magnolol and HTS could provide further protection in mesenteric ischemia reperfusion injury.

Methods: Male C3H/HeOuJ mice were randomly segregated into the following groups: sham-operated (sham), vehicle treatment and mesenteric ischemia reperfusion (MSIR) (vehicle-treated), magnolol treatment and MSIR (magnolol-treated), HTS treatment and MSIR (HTS-treated), as well as co-administration of magnolol plus HTS and MSIR (combined-treated). In MSIR, mice were subjected to mesenteric ischemia for 60 min followed by reperfusion for 30 min. Lung injury was evaluated by lung edema (water ratio) and myeloperoxide (MPO) activity; RNA expression of inducible nitric oxide synthetase (iNOS), TNF-α, and IL-6 were assayed by real time RT-PCR. The formation of peroxynitrite in plasma was assayed by the peroxynitrite-dependent oxidation of dihydrorhodamine 123 (DHR 123) to rhodamine.

Results: Compared with those in the sham-treated group, lung edema and MPO activity, expressions of iNOS, TNF-α and IL-6, and plasma peroxynitrite were significantly increased in the vehicle-treated group. Significant attenuations of these parameters were found in the magnolol-treated or HTS-treated animals. Combined treatment of magnolol and HTS further suppressed the lung edema, iNOS, and TNF-α expressions, and plasma peroxynitrite, compared with the results of a single treatment of magnolol or HTS.

Conclusions: Compared with single-agent use, co-administration of magnolol and HTS further decreases iNOS expression and plasma peroxynitrite as well as the degree of lung injury from MISR. These results may provide another treatment measure for post-injury immunomodulation.