Effect of pulsed electromagnetic field on rat muscle ischemia reperfusion injury

Introduction and Aim: Ischemia is defined as the reduction or cessation of blood flow to a tissue. Reperfusion is maintaining the blood flow to the tissue again. These changes in blood flow to the tissues cause damage. This damage depends on the cause, duration, and severity of ischemia, as well as reperfusion. It is so-called ischemia reperfusion (I-R) injury. Although I-R injury has a complex pathophysiological process accompanied by many mechanisms, the elucidation of these mechanisms has led to a search for solutions in order to prevent the damage. Despite numerous surgical and pharmacological studies, a safe treatment that can reverse I-R damage has not been found yet. Pulsed electromagnetic field (PEMF) therapy is a treatment modality that has been used for many years and has proven its effectiveness on bone healing, wound healing, tissue regeneration, and anti-inflammatory properties. Our study aims to examine the effects of PEMF application on skeletal muscle damage after I-R injury in the lower extremity of the rat. Material and Method: 40 male Wistar-Albino rats, aged between 4-6 months, with a starting weight of 250-350 g, were divided into 4 different groups. Group 1 was the control group and no application was made (n=10). In groups 2, 3, and 4, the blood flow of the lower extremities of the rats was stopped in accordance with the hindlimb ischemia method by constricting the femoral artery-vein system with micro clips, and ischemia was created for 4 hours. Reperfusion was achieved after 4 hours. Group 2 did not receive any treatment (n=10). In Group 3, PEMF treatment was applied for 1 hour per day for 30 days after I-R damage was created (n=10). In Group 4, PEMF treatment was applied 2 hours per day for 30 days after I-R damage was created (n=10). After 30 days, the lower extremities of the rats were evaluated macroscopically by Ischemia Score. After the application of indocyanine green (ICG) from the tail vein, the lower extremity perfusion was visualized and mapped with the SPY device. After the evaluation, the rats were sacrificed and samples were taken from the gastrocnemius muscles. The samples were examined under a light microscope and electron microscope. In addition, in order to examine the muscle functions biophysically, the isometric contraction forces of the muscles were evaluated by taking them into an isolated organ bath. Results: As a result of the macroscopic evaluation according to the Ischemia Score, all groups were evaluated as Normal. Percentage mapping was performed in the imaging performed on the SPY device, and it was observed that the perfusion in Group 3 and Group 4 was better than Group 2 and similar to Group 1. In the light microscope, it was observed that the leukocyte density decreased in Group 3 and Group 4, and the decrease in Group 3 was more in the comparison between these groups. It was observed that lymphocyte density increased in all groups in which I-R was created. Neovascularization was evaluated by capillary density, and it was observed that it increased significantly in Group 3 and Group 4, where PEMF was applied. In the electron microscopy examination, reversal of muscle degenerations in Group 3 and Group 4 was observed, and the morphology in Group 4 was similar to Group 1. A statistically significant difference was observed when the contraction forces were XIII compared in the evaluation of isometric muscle contraction (p<0.01). Group 1 and Group 4 were observed to have similar strengths. When the contraction times were compared, a significant difference was observed between the groups (p<0.024). There was no statistically significant difference between relaxation times. Conclusions: There are many studies on the effects of PEMF application in the literature, and healing effects on tissues, especially on bone, and anti-inflammatory effects have been demonstrated. However, the limited number of studies on I-R injury and the fact that these studies did not evaluate the loss of function after I-R injury makes our study different. PEMF application can be considered as a treatment option because it has effects on many pathways involved in the mechanism of I-R injury, has accelerating effects in the recovery process after the injury, and has no systemic side effects. In addition, the fact that it is effective in restoring the loss of strength in the skeletal muscle after I-R injury makes PEMF treatment different from all other treatment modalities.