Which is worse, a repeated short time ischemia or a continuous long time ischemia? An effect of intermittent reperfusion on tissue damage due to ischemia-reperfusion

Objective

The aim of this study is to clarify the effect of repeating ischemia-reperfusion on the tissue damage or which is worse, continuous long time ischemia before reperfusion or repeated short time ischemia-reperfusion before definitive reperfusion.

Materials and methods

Small intestinal segments of Wister male rats were clamped with its mesenterial vessels. In group A, the clamped segment was released 60 min after the clamp; in group B, clamped segment was released 30 min after the clamp (for 10 min), re-clamped, and definitively released 60 min after the first clamp; and in group C, the procedure of clamp-intermittent release-definitive release was similar to that of group B and super-oxide dismutase and catalase were given during the period of intermittent release. Tissue lipid peroxide (LPO) and the activity to produce oxygen free radicals of neutrophils in the draining vein from involved intestinal segment (chemiluminescence [CL]) were measured 10 min after definitive release.

Results

In group A, LPO and CL were increased from 19 to 43 nmol/g and from 30 to 43 counts per cell (cpc), respectively; in group B, those were increased to 118 nmol/g and 64 cpc, respectively, and in group C, 78 nmol/g and 31 cpc, respectively.

Conclusion

In some condition, tissue damage due to reperfusion injury derived from oxygen free radicals is more severe in repeat of short time ischemia with intermittent release than in long continuous ischemia.