The kinetics of copper-zinc superoxide dismutase in experimentally induced ischemia-reperfusion injury of the canine jejunum

[Effect of ischemic postconditioning on oxidative stress and structural tissue changes in intestinal warm ischemic and autotransplantation models]

INTRODUCTION/AIM

Our study investigated the effect of ischemic postconditioning (IPO) in intestinal warm ischemia/reperfusion (I/R) and autotransplantation models.

MATERIALS AND METHODS

Warm ischemia was performed by occlusion of superior mesenteric artery for 1, 3 and 6 hours in white domestic pigs (n = 15). Prior to 3 hours reperfusion the intestine was postconditioned by 3 cycles of 30-seconds ischemia and 30-seconds reperfusion (IPO protocol). In the cold ischemia group (n = 15) the bowel was preserved in University of Wisconsin solution for 1, 3, and 6 hours. Prior to 3 hours reperfusion IPO protocol was applied, too. Tissue samples were collected after laparotomy (control) and at the end of the reperfusion periods. As far as oxidative stress markers, malondialdehyde and reduced glutathione (GSH) levels and superoxide dismutase (SOD) activity were determined. Tissue damage was evaluated by qualitative (Park-classification) and quantitative (Scion Image) methods.

RESULTS

As regards oxidative stress parameters, lipidperoxidation decreased and the protective effect of endogenous antioxidants (GSH, SOD) retained significantly by IPO procedure at the end of reperfusion. Tissue injury correlated significantly by the duration of warm ischemia and cold preservation. Quantitative analysis demonstrated that IPO ameliorated tissue injury in each group (p < 0.05).

CONCLUSION

IPO significantly attenuated intestinal oxidative stress and morphological damages in warm and cold I/R models.

Effects of in vivo freezing and mannitol in intestinal ischaemia-reperfusion injury

PURPOSE

The main purpose of this study was to investigate whether in vivo freezing and mannitol administration can protect the small intestine against ischaemia-reperfusion (I-R) injury.

METHODS

Fifty male Sprague-Dawley rats (200-225 g) were divided into 5 groups each containing 10 rats; group SO, sham operation group; group I, mesenteric ischaemia group; group R, ischaemia-reperfusion (I-R); group FR, I-R plus in vivo freezing; group MR, I-R plus mannitol treatment. Intestinal ischaemia for 30 min and reperfusion for 60 min were applied. Ileum specimens were obtained to determine the tissue levels of malondialdehyde (MDA) and histological changes.

RESULTS

The mucosal injury scores of group R were significantly higher than those of the group I (P<0.0001). The mucosal injury scores in the groups FR and MR were significantly lower than the group R (P<0.0001 and P<0.0001, respectively). In the group FR, mucosal injury scores were not significantly different from those of group I (P=0.123). However, mucosal injury scores of group MR were significantly less when compared to those of group I (P=0.01). Mean MDA levels of group R were significantly higher than those of the group I (P<0.0001). Mean MDA levels of groups FR and MR were significantly lower than those of group R (P<0.0001 and P<0.0001, respectively). In addition, MDA levels of group FR were significantly higher than those of group MR (P<0.0001).

CONCLUSION

In conclusion, these observations suggest that the in vivo freezing of SMA and the pre-treatment with mannitol before reperfusion period may be useful in preventing intestinal reperfusion injury.

Nonspecific ulcerated jejunitis as an unusual complication of laparoscopic cholecystectomy: report of a case

We describe herein the case of a 65-year-old man in whom a lower gastrointestinal hemorrhage developed a few days after he underwent an elective laparoscopic cholecystectomy. A laparotomy was performed on postoperative day 16 and a jejunal segment containing mucosal changes and oozing ulcers was resected. Pathologic examination of the specimen revealed "nonspecific ulcerated jejunitis." There is no explanation for the etiopathogenesis of this pathology; however, we concluded that this clinical picture may be attributed to ischemia-reperfusion injury that occurred following an ischemic period caused by the pneumoperitoneum during laparoscopic surgery.

Copper/zinc superoxide dismutase, nuclear DNA content, and progression in human gliomas

To our knowledge, there have been no previous reports regarding the immunohistochemistry and image cytometry to demonstrate elevated Copper/zinc superoxide dismutase (Cu/Zn SOD) expression and numbers of the clonal cells in human gliomas. In 30 well-studied patients with gliomas, immunoreactivity for Cu/Zn SOD and cytometric evidence of DNA ploidy in the G2M cell cycle phase were evaluated from routinely prepared tissue blocks. Cu/Zn SOD positive tumor cells were shown in 8 of 13 glioblastomas (mean quantitative immunoreactivity SOD score; 1), 3 of 8 anaplastic gliomas (score; 0.6), and none of 9 low-grade gliomas. The differences in SOD score was not significant. In hypertetraploid glioblastomas, time to progression was shorter than for hypertetraploid of anaplastic gliomas, while SOD scores were not significantly different. The same relationship held for tetraploid specimens. Considering variables in combination, hypertetraploid gliomas with high SOD immunoreactivity showed a significantly short time to progression (p < 0.05) (1-5 months after radiotherapy and chemotherapy) compared with hypertetraploid, low-SOD immunoreactivity gliomas or tetraploid, low-SOD immunoreactivity gliomas. The tumor cells with high SOD activity also tended to be resistant for radiotherapy and anticancer drugs. Those results were suggested that the high grade glioma with a single clone and low SOD activity were effective for radiotherapy associated with oxidative stress, and that the high grade gliomas with more than two clones and high SOD activity were very less effective for same therapy. Cu/Zn SOD activity and the degree of the clonality in human gliomas should be very important factors influencing a choice of oxidative cytotoxic treatment.

Immunohistochemical study on tissue transglutaminase and copper-zinc superoxide dismutase in human myocardium: its relevance to apoptosis detected by the nick end labelling method

The influence of free radicals on apoptosis was studied in the human heart; 45 autopsy cases were examined by the nick end labelling method (NELM) that detects DNA fragmentation. Immunostaining for copper-zinc superoxide dismutase (CuZn-SOD) and tissue transglutaminase (tTG) induced frequently during apoptosis were also studied. Positive immunoreaction for tTG was detected in mucinous degeneration of myocardial cells; these same cells were also positive for CuZn-SOD but negative for NELM. Myocardial cells showing basophilic alterations after haematoxylin and eosin staining were also positive for CuZn-SOD but negative for the other markers examined. Positive nuclear reaction by NELM was only observed in myocardial cells showing contraction band necrosis or irregularly shaped nuclei surrounding recent or long-standing infarcted foci. In these the other two markers were negative. Since mucinous degeneration lacks the distinguishing morphological features of apoptosis, immunoreactive tTG in this lesion may not imply that the cells are undergoing apoptosis. tTG can be induced in non-apoptotic conditions and may not be involved in apoptosis induced by infarction. Histological disassociation between CuZn-SOD expression and apoptosis suggests the possibility of a cytoprotective role played by endogenous CuZn-SOD against free radical generation in the human heart.