Experimental Study Of Renal Injury After Skeletal Muscle Ischemia/reperfusion Injury

Ischemia reperfusion injury is a common and severe complication in surgery, it happens when ischemic tissue and organ regain blood flow, but the functional impairment and structure injury is not relieved, it may even worse than before. The injury does not occur only in the Ischemia/Reperfusion local site, but also the organ far apart by releasing oxygen free radical, activating neutrophile granulocyte, releasing inflammatory cytokine. Limbs trauma, replantation of a severed limb, misapplication of tourniquet, osteofascial compartment syndrome and arterial embolism are common causes of limb reperfusion injury, and the secondum renal injury and orresponding disfunction is complicated, which has a higher mortality rate. The mechanism of skeletal muscle ischemia/reperfusion injury becomes more complicated as there are many factors involved. At present, oxygen free radical, calcium overload and neutrophil are the popular ideas, and nitrogen monoxidum, no reflow and apoptosis are also included. The renal injury after skeletal muscle ischemia/reperfusion injury is more complicated, it is thought that the main pathogenesis of renal injury is myoglobin casts shapes in kidney tubules and block up it. Recent research find that ferroprotoporphyrin from myoglobin plays an important role in the renal injury, except for shaping myoglobin casts, OH- free radicals inducing by heme is more important in oxidize injury of kidney tubules. There is plenty of LDH in normal skeletal muscle, whose sarolemma permeability rises on the early stage of cell injury, so enzyme in the cell is released into blood, resulting in the corresponding changes in the serum enzyme, which can rise as the skeletal muscle injury worsens. So the serum LDH can be a sensitive index of the skeletal muscle injury,the level of which can reflect the degree of skeletal muscle injury. Cr is micromolecule which can filter through glomerulus and is seldom absorbed by kidney tubules, so the serum Cr concentration is chiefly determined by glomerular filtration function, it is a main way to learn the renal function by testing serum Cr concentration.Objective: To investigate the pathogenic mechanism of renal injury after skeletal muscle ischemia/reperfusion injury and the effective treatment of it, we test the serum LDH and Cr level of different non-operation, simply ischemia and ischemia/reperfusion group, at the same time we observe the pathological change of renal tissue of each group after HE staining. Methods: Selected 30 healthy male SD rats, whose weight was 250±20g, they were made into 3 groups at random. A group: there were 10 rats non-operation, which just gave a 3% pentobarbital sodium (3mg?100g) injection to enterocoelia as anaesthesia, and gave a treatment after 4h. B group: there were 10 rats ischemia for 4h, after the same anaesthesia as A group, we made a skeletal muscle ischemia model by dissecting the rats to give a block of abdominal aorta below the level of renal artery with Bulldog nipper, and give a full-thickness suture after confirming the block of blood flow. We gave a treatment after 4h. C group: constructed skeletal muscle ischemia model at first just as B group, unclamped Bulldog nipper to give a reperfusion for 4h after blocking the abdominal aorta blood flow for 4h, then gave a treatment. We gave hemospasia from heart at the time of each group set before to test the change of serum LDH and Cr level, and got fresh renal tissue with a sharp razor blade, which were made into paraffin section and given HE staining to observe the change of tissue morphous. We made a statistical treatment of the experimental result with a software of SPSS 17.0.Results: Compared the simply ischemia B group with non-operation A group, there is no significant change in the level of serum Cr and LDH. There is a significant difference between the ischemia/reperfusion C group and simply ischemia B group in the level of serum Cr and LDH, which means that the skeletal muscle and renal injury of C group is much higher than that of B group. Observation of renal tissue at light microscope was that the morphous of glomerulus was normal, renal tubule lining up in order, the morphous of epithelial cell of renal tubule and endothelial cell of vessel of kidney normal, endochylema well-distributed and erythrophil, nucleus not disfiguration, the chromatospherite clear and no inflammatory cell infiltrate in non-operation group, which was the same as the simply ischemia B group. However the glomerulus is hyperemia, endothelial cell swelling obviously, lumina of renal tubule stenotic, integrity of epithelial cell destroyed, with inflammatory cell infiltrate in the ischemia reperfusion C group.Conclusions: The injury of skeletal muscle is not relieved after ischemia/reperfusion, on the contrary it has a more severe functional impairment and structure injury, at the same time results in the injury of renal tissue.