Protective influence of edaravone on cellular membrane and mitochondria of replanted rat extremities following ischemia/reperfusion injury due to cryopreservation and rewarming

ABSTRACT

BACKGROUND:

A lot of important organs are worthless for clinical application because they are hard to store for a long time. In addition, tissues or organs which are dealt with cryopreservation also attack ischemia/reperfusion injury with the recovery of blood flow; especially, skeletal muscle is the most involved tissue.

To observe the protective influence of edaravone on cellular membrane and mitochondria of replanted rat extremities following ischemia/reperfusion injury due to cryopreservation and rewarming.

Randomized contrast animal study.

Basic Medical College of Southern Medical University; Department of Hand and Foot Surgery, Shandong Provincial Hospital.MATERIALS The experiment was carried out in the Cryopreservation Laboratory, Shandong Provincial Hospital from April to November 2006. A total of 36 healthy adult male Wistar rats were provided by Experimental Animal Center of Medical College of Shandong University. All rats were randomly divided into control group, cryopreservation group and edaravone group with 12 in each group.

Femoral artery and vein of rats in control group were exposured, but extremities were not blocked. Rats in other two groups were used to establish ischemia/reperfusion injury models of replanted extremities. Before cryopreservation, their right hindlimbs were cut off and maintained in liquid nitrogen container for 1 month. After the operation mentioned above, the broken limbs were rewarmed, perfused with routine eluant and replanted. Four hours later, blood supply of extremities was recirculated and the samples were selected. Eluant in edaravone group contained 0.5 mg/kg edaravone. Samples of skeletal muscle were selected at the same time point to establish cellular membrane and extract mitochondria. Furthermore, fluorescence polarization of cellular membrane (reflecting liquidity in cellular membrane lipid area), malondialdehyde (MDA) content of mitochondria, superoxide dismutase (SOD) activity and respiratory controlling rate were measured; meanwhile, mitochondrial ultrastructure of skeletal muscle was observed under transmission electron microscope.MAIN OUTCOME

①Fluorescence polarization of cellular membrane, MDA content of mitochondria, SOD activity and respiratory controlling rate of skeletal muscle; ②mitochondrial ultrastructure of skeletal muscle.

All 36 rats were involved in the final analysis without any loss. ①SOD activity and respiratory controlling rate of mitochondria in skeletal muscle The values of these two items were higher in edaravone group that those in cryopreservation group (P＜0.05).②Fluorescence polarization of cellular membrane and MDA content of mitochondria in skeletal muscle The values of these two items were lower in edaravone group than those in cryopreservation group (P＜0.05). ③Mitochondrial ultrastructure of skeletal muscle Injured degree of skeletal muscle was milder in edaravone group than that in cryopreservation group.

Edaravone can relieve ischemia/reperfusion injury of skeletal muscle and protect cellular membrane and mitochondria of skeletal muscle. Its mechanism may be related to directly inhibiting hydroxy free radicals, increasing SOD activity of skeletal muscle, reducing generation of MDA and promoting normal oxidative phosphorylation.