[Changes in phospholipids after repeated induced sublethal spinal cord ischemia in rabbits].
Degradation of membrane bound phospholipids in CNS during ischaemia begins with extreme rapidity. Sublethal ischaemia influences ischaemic tolerance in the affected neurons and is stressful enough to induce neuronal changes such as postischaemic hypoperfusion, transient suppression of protein synthesis and induction of stress (HSP) proteins. It seems, that the nature of factors responsible for ischaemic tolerance may involve the activation of multiple different systems. The aim of this study was to investigate the changes of phospholipids in gray matter regions of spinal cord following sublethal ischaemia repeated in long intervals of reperfusion. Male rabbits, weight range 2.5-3.5 kg were used in the experiment. They were divided in following groups : 1. control animals; 2. animals subjected to 25 min ischaemia; 3. animals subjected to 25 min ischaemia and 3 h of reperfusion; 4. animals subjected to sublethal (8-8-9 min) ischaemia repeated in long-lasting (8-8-24 h) intervals of reperfusion. Phospholipids were separated by thin layer chromatography, lipidic phosphorus was assessed spectrophotometrically. Sublethal ischaemia repeated in long-lasting intervals of reperfusion increased the concentration of phospholipids to control levels in all gray matter regions. The resynthesis in the dorsal horns, of PC and PE in the ventral horns and of PC in the intermediate zone. An excessive renewal of phospholipids after sublethal ischaemia repeated in longer intervals of reperfusion was most pronounced in the eh dorsal horns of the spinal cord and can be the result of many defensive cellular mechanisms.