Background: The aim of this study was to investigate the effects of intraluminal hyperoxygenated solution (HOS) on enterocyte mitochondrial structure and respiratory function after intestinal ischemia-reperfusion (IR) in rabbits.
Materials and methods: Thirty-two rabbits were divided randomly into four groups: control group in which sham operation was performed (Sham group), ischemia-reperfusion group (IR group), and two HOS treatment groups (H1 group and H2 group). Intestinal IR model was produced by clamping superior mesenteric artery (SMA) with an atraumatic vascular clamp for 1 h, followed by reperfusion for 2 h. Animals in the H1 group and H2 group received intraluminal HOS infusion for 1 h immediately after occlusion of SMA, and the rates of infusion were 10 and 20 mL/kg.h, respectively. After 2 h of reperfusion, enterocyte mitochondria morphological quantitative analysis was made with electron microscopy and biogenetics stereology, and the following parameters, including mitochondrial respiratory control ratio (RCR), intestinal O(2) extraction ratio (ER), and mucosal ATP contents, were measured, respectively.
Results: After IR, the mitochondria was severely swollen with broken cristae, and mean transaction area, diameter, surface density, and volume density of the mitochondria increased significantly. Meanwhile, specific surface and numeral density of the mitochondria decreased significantly. The mitochondrial RCR, intestinal O(2) ER, and mucosal ATP contents were all decreased significantly. There were no differences in all parameters between the IR group and H1 group. In the H2 group, the mitochondria were slightly swollen, and mean transaction area, diameter, surface density, and volume density of the mitochondria were all significantly lower, with the specific surface and numeral density of the mitochondria significantly higher compared with the IR group. The mitochondrial RCR, intestinal O(2) ER and mucosal ATP contents in H2 group were all significantly higher than those in IR group.
Conclusions: Intraluminal HOS infusion at 20 mL/kg.h during ischemia ameliorates structural and functional changes of enterocyte mitochondria associated with intestinal IR injury, which is a safe, simple, and effective measure to protect the intestine from IR injury.