Protection against intestinal injury from hemorrhagic shock by direct peritoneal resuscitation with pyruvate in rats.

OBJECTIVE: We explored the effects of direct peritoneal resuscitation with pyruvate-peritoneal dialysis solution (PDS) following intravenous resuscitation (VR) on intestinal ischemia-reperfusion injury in rats with hemorrhagic shock (HS). METHODS: Fifty rats were randomly assigned equally to five groups. In group sham, a surgical operation was performed on rats without shock or resuscitation. In group VR, rats were subjected only to VR. In groups NS, LA, and PY, direct peritoneal resuscitation was performed with normal saline (NS), lactate-based PDS (Lac-PDS), and pyruvate-based PDS (Pyr-PDS), respectively, after VR. Mean arterial pressure was monitored in the right common carotid artery. Two hours after resuscitation, the lactate level in arterial blood and the wet weight/dry weight ratio of the intestine were determined. The intestinal mucosal damage index was estimated, and ultrastructural changes in the intestinal mucosa were observed. Malondialdehyde, myeloperoxidase, nitric oxide, and tumor necrosis factor α levels were also measured. RESULTS: Two hours after HS and resuscitation, the increase in arterial blood lactate and intestinal wet weight/dry weight ratio declined significantly in rats from Groups LA and PY compared with groups VR and NS, whereas group PY was more advantageous in the changes of these parameters. The intestinal mucosal damage index and ultrastructural changes were also improved in groups LA and PY when compared with groups VR and NS. Protection was more apparent with Pyr-PDS than Lac-PDS. Hemorrhagic shock resulted in a significant increase in malondialdehyde levels and myeloperoxidase activity and was accompanied by overexpression of tumor necrosis factor α and a reduction in nitric oxide levels. These changes were significantly attenuated by Lac-PDS and Pyr-PDS at 2 h after resuscitation, and Pyr-PDS showed more effective protection for the intestine than Lac-PDS. CONCLUSIONS: Direct peritoneal resuscitation with Lac-PDS and Pyr-PDS after VR alleviated intestinal injury from HS in rats, and Pyr-PDS was superior to Lac-PDS in its protective effect. Mechanisms of action might include the elimination of free oxygen radicals, reduction of neutrophil infiltration, inhibition of the inflammatory response, and regulation of intestinal mucosal blood flow and barrier function.

Transduced PEP-1-heme oxygenase-1 fusion protein protects against intestinal ischemia/reperfusion injury.

BACKGROUND: Heme oxygenase-1 (HO-1) has been shown to have antioxidant and anti-apoptotic properties. The present study transduced HO-1 protein into intestinal tissues using PEP-1, a cell-penetrating peptide, and investigated its potentiality in prevention against intestinal ischemia/reperfusion (I/R) injury. MATERIALS AND METHODS: PEP-1-HO-1 fusion protein was administered intravenously to explore the time and dose characteristics through measuring serum HO-1 levels. Twenty-four male Sprague-Dawley rats were randomly divided into three groups: sham, intestinal I/R (II/R), II/R + PEP-1-HO-1 fusion protein (HO). The model was established by occluding the superior mesenteric artery for 45 min followed by 120 min reperfusion. In HO group, PEP-1-HO-1 was administered intravenously 30 min before ischemia, whereas animals in sham and II/R groups received the equal volume of physiological saline. After the experiment, the intestines were harvested for determination of histologic injury, wet/dry ratio, enzyme activity, apoptosis, and His-probe protein (one part of PEP-1-HO-1). RESULTS: Levels of serum HO-1 were dose- and time-dependent manner after intravenous injection of PEP-1-HO-1. I/R caused deterioration of histologic characteristics and increases in histologic injury scoring, wet/dry ratio, myeloperoxidase activity, malondialdehyde, and intestinal apoptosis. These changes were also accompanied by a decrease in superoxide dismutase activity (P < 0.05). PEP-1-HO-1 treatment significantly reversed these changes (P < 0.05). Furthermore, His-probe protein expression was only detected in PEP-1-HO-1-treated animals. CONCLUSION: Treatment of PEP-1-HO-1 attenuates intestinal I/R injury, which might be attributable to its antioxidant and anti-apoptotic roles of HO-1.