Abstract

The objective of this work was to evaluate the effect of a bradykinin‐potentiating factor (BPF) isolated from Leiurus quinquestriatus scorpion venom as a natural modulator of radiation‐induced cardiac damage. Four groups of rats were treated as follows; control group, group receiving BPF (1 µg/g b.wt i.p./biweekly) for 4 weeks, group irradiated at 6 Gy, group receiving BPF post‐irradiation for 4 weeks. Irradiation induced a significant elevation of myocardial parameters: atrial natriuretic peptide (ANP), cardiac troponin I (cTnI), potassium (K+) and creatine kinase (CK); vascular indices: lactate dehydrogenase (LDH), inducible nitric oxide synthase (iNOS) and endothelin I; oxidative stress indices: malondialdehyde (MDA) associated with a significant depletion of both reduced glutathione (GSH) in the cardiac tissue homogenate and serum ferric reducing antioxidant power (FRAP) depletion and significantly reinforced elevation of Renin Angiotensin Aldosterone System (RAAS) indices: serum angiotensin II (AngII) and aldosterone, and also protein expression of cleaved caspase‐3 and cyclophilin A. BPF administration altered the biochemical damage of radiation, specifically inhibited AngII formation, aldosterone release and prevented the histopathological and immunohistochemical alterations which were observed in cardiac tissue with significant reduction in mean arterial blood pressure (MAP) caused by irradiation. In conclusion, biochemical assays, histopathological and immunohistochemical findings of the present study demonstrated that exogenous BPF isolated from scorpion venom reduced the cardiomyopathy alterations induced by irradiation via remodelling of the RAAS pathway.