Radiofrequency electromagnetic field ınhibits HIF-1 alpha and activates eNOS signaling to prevent intestinal damage in a model of mesenteric artery ischemia in rats

Abstract

Background: Pathologies such as mesenteric artery ischemia and reperfusion (MIR) can lead to many organ dysfunctions, including the brain and heart through damage mechanisms induced in response to hypoxic conditions. Radiofrequency electromagnetic field (RF-EMF) can increase the vascularization of tissues by providing endothelial nitric oxide synthase (eNOS)-mediated nitric oxide (NO) release from the endothelium. The aim of this study is to investigate the protective effect and mechanism of RF-EMF in ischemic intestinal injury in the experimental MIR model. Methods: In the study, 32 Wistar Albino rats were divided into four groups: Sham group, MIR group, Prophylactic (Pr) RF-EMF + MIR group, MIR + Therapeutic (Tr) RF-EMF group. At the end of the experimental phase, after sacrifice, blood samples and the 10 cm terminal ileum part of the intestinal tissues was cut and collected for histopathological, immunohistochemical, genetic and biochemical analyses. Results: In the MIR group, Cas-3, TNF-α, VEGF, BAX and HIF-1α expressions increased, while OSI levels, and PCNA, BCL2 and eNOS expressions decreased. In addition marked hyperemia, hemorrhage, edema, inflammatory cell infiltrations, and erosion or ulcers were observed in MIR group. Pr (especially in eNOS expression) and Tr (especially in pathological findings) treatment of RF-EMF reversed all these parameters but more effective recovery was observed in Tr treated group. Conclusion: RF-EMF-treatment preserved the vascularization of the tissue and decreased hypoxia-induced oxidative stress, inflammation, and apoptosis.

Keywords: Apoptosis; Electromagnetic field; Mesenteric ischemia; Oxidative stress Radiofrequency.

Figure 1

The summarize of the cell damage mechanism in MIR. MIR: Mesenteric artery ischemia and reperfusion, POC: Prooxidant cytokines, PIC: Proinflammatory cytokines, TOS: Total oxidant status, IL-6: Interleukin-6, NO: Nitric oxide, HIF-1α: Hypoxic-induced factor-1 alpha, INOS: Inducible nitric oxide synthase, VEGF: Vascular endothelial growth factor, eNOS: endothelial nitric oxide synthase, BAX: B-cell lymphoma 2 Associated X, TNF-α: Tumor necrosis factor-alpha, Cas-3: Caspase-3, PCNA: Proliferating cell nuclear antigen.

Figure 2

Experimental procedures of the study. MIR: Mesenteric Ischemia and Reperfusion group, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field group, Tr-RF-EMF: Therapeutic radiofrequency electromagnetic field group.

Figure 3

Oxidative stress parameters of the study. MIR: Mesenteric Ischemia and Reperfusion group, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field group, Tr-RF-EMF MIR: Therapeutic radiofrequency electromagnetic field group, TAS: Total antioxidant status, TOS: Total oxidant status, OSI: Oxidative stress index, Values are presented as means ± standard deviation. Oneway ANOVA test was used.

Figure 4

Representative histopathological view of the intestine. (A) Normal histology in the control group. (B) Marked ulcers, edema, and inflammatory cell infiltrations (arrow) in the MIR group. (C) Significant decrease in pathological findings in the Pr-RF-EMF group. (D) Almost normal appearance in the Tr-RF-EMF group. HE, Scale bars = 50 μm. MIR: Mesenteric Ischemia and Reperfusion, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field, Tr-RF-EMF: Therapeutic radiofrequency electromagnetic field.

Figure 5

Cas-3 expressions among the groups. (A) Very slight Cas-3 expressions in the sham group. (B) Marked increase in Cas-3 in the MIR group. (C) Slight Cas-3 in the prophylactic RF group. (D) Negative Cas-3 expressions in the therapeutic RF group. Scale bars = 50 μm. MIR: Mesenteric Ischemia and Reperfusion, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field, Tr-RF-EMF: Therapeutic radiofrequency electromagnetic field.

Figure 6

PCNA expressions among the groups. (A) Very slight PCNA expressions in the sham group. (B) Marked decrease in PCNA expressions in the MIR group. (C) Slight PCNA expressions in the prophylactic RF group. (D) PCNA expressions in the therapeutic RF group. Scale bars = 50 μm. MIR: Mesenteric Ischemia and Reperfusion, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field, Tr-RF-EMF: Therapeutic radiofrequency electromagnetic field.

Figure 7

TNF-α expressions among the groups. (A) Very slight TNF-α expressions in the sham group. (B) Marked increase TNF-α expressions in the MIR group. (C) Slight TNF-α expressions in the prophylactic RF group. (D) Negative TNF-α expressions in the therapeutic RF group. Scale bars = 50 μm. MIR: Mesenteric Ischemia and Reperfusion, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field, Tr-RF-EMF: Therapeutic radiofrequency electromagnetic field.

Figure 8

mRNA expression levels of tissues. MIR: Mesenteric Ischemia and Reperfusion group, Pr-RF-EMF: Prophylactic radiofrequency electromagnetic field, Tr-RF-EMF Therapeutic radiofrequency electromagnetic field, BAX: BCL2 Associated X, BCL2: B-cell lymphoma 2, HIF1 α: Hypoxia-inducible factor 1 alpha, VEGF: Vascular Endothelial Growth Factor, eNOS: Endothelial nitric oxide synthase.