The effect of surgical and chemical denervation on ischaemia/reperfusion injury of skeletal muscle

Abstract

Denervation decreases skeletal muscle's energy needs and alters its metabolism and circulation. Our study was designed in two stages to investigate the effects of surgical and chemical denervation on the ischaemia/reperfusion injury of skeletal muscle. Degenerative histological analysis, apoptosis scoring and tissue levels of malonyl-di-aldehyde (MDA) and nitric oxide end products (NOx) were studied to understand the extent of ischaemia/reperfusion injury of skeletal muscles. In the first stage, the effect of surgical denervation was investigated in four groups each containing six rats. The right biceps femoris muscle was used as the experimental muscle flap model. In the control group, only the ischaemia/reperfusion cycle was applied. Ischaemia was created by a tourniquet strictly wrapping the right lower extremity for 4h. After ischaemia, the tourniquet was cut, and the extremity was reperfused for another 4h. In the experimental groups, surgical denervation was applied 1 day, 7 days and 30 days before the ischaemia/reperfusion cycle. On the second stage, the effect of chemical denervation with botulinum toxin type-A (BoNT-A) was investigated in three groups, each containing six rats. In the experimental groups, BoNT-A was applied 1 day, 7 days and 30 days before the ischaemia/reperfusion cycle. The control group had the worst scores in all experiment parameters. Degenerative histology and apoptosis scores were significantly better in groups to which BoNT-A and SD were applied 1 or 7 days before the ischaemia/reperfusion cycle. Regarding tissue levels of MDA and NOx, the experiment groups had significantly better scores comparing to the control group. Both surgical and chemical denervation applied before muscle transfer increased muscle ischaemia tolerance. With similar experimental outcomes, denervation with BoNT-A can be preferred to surgical denervation because of its abundant clinical availability and it can be applied without any secondary surgery.