Sarcolemmal integrity during ischaemia and reperfusion of the isolated rat heart

Abstract

The effects of ischaemia and reperfusion on sarcolemmal permeability were studied in the isolated rat heart using an ionic lanthanum probe technique. Detection of increased permeability after exposure to short periods of ischaemia without accompanying reperfusion effects was achieved by employing a substrate-free, low calcium saline solution as vehicle for ionic lanthanum. Quantifiable results showed a rapid increase in sarcolemmal permeability in the subendocardium after 15 min of ischaemia, with the subepicardium showing similar alterations after longer periods. Reperfusion after 15 min of ischaemia led to recovery of normal permeability characteristics, correlating well with ultrastructural and functional recovery. Reperfusion after 25 min of ischaemia did not allow recovery of sarcolemmal permeability, ultrastructure, or function. These results show a clear correlation between the development of irreversible myocardial damage and increased sarcolemmal membrane permeability.

Lanthanum probing of cell membrane permeability in the rat heart: Pathological versus artefactual alterations

“…After 15 minutes of NICA, lanthanum accumulated intracellularly, particularly in and around mitochondria, in the form of discrete spherical deposits of varying size in approximately 70% of the myocytes (Fig. 7b, actual data published in paper by Harper and Lochner, 1989). Results of La influx were qualitatively similar after 25 minutes of NICA (Fig.…”

“…This may be a misleading assumption as glutaraldehyde has recently been shown to alter natural membrane permeability in muscle (Harper, 1986). Unable to obtain credible results using the latter technique, we recently modified the vital lanthanum probe technique and by minimizing reperfusion effects were able to demonstrate differences in sarcolemmal permeability between hearts probed at the end of the ischaemic and reperfusion periods respectively (Harper and Lochner, 1989). In this model we found that the subendocardial sarcolemma became permeable to lanthanum after only 15 minutes of NICA.…”

“…Both ionic and so-called colloidal lanthanum have been used and application of the fixative by means of perfusion, which is clearly a superior method for preservation of ultrastructure (Bullock, 1979) has been compared with immersion fixation. Alterations in the ischaemic myocardia probed with lanthanum prior to fixation (Harper and Lochner, 1989) were used for comparison with the present results, showing that fixation prior to lanthanum probing causes an artefactual increase in membrane permeability.…”

Effects of Specific Sodium/Hydrogen Exchange Inhibitor During Cardioplegic Arrest

“…Otherwise, after 40 minutes of ischemia, sodium continues to increase during reperfusion. Harper and Lochner [27] found that after 25 minutes of normothermic ischemia, isolated rat hearts did not recover sarcolemmal permeability, ultrastructure, or function. Malloy and coauthors [24] also observed that the recovery of myocardial function correlated with the return of intracellular sodium levels (measured by NMR) to baseline during reperfusion.…”

Quantification of the total Na,K-ATPase concentration in atria and ventricles from mammalian species by measuring3H-ouabain binding to intact myocardial samples. Stability to short term ischemia reperfusion

“…The latter may be of special interest on the basis of the concept that ischemic myocytes may enter a reversible phase before irreversible injury occurs (12,25).…”