Epidemiological evidence demonstrates positive correlation between environmental and occupational
arsenic or
fluoride exposure and risk to various cardio-respiratory disorders.
Arsenic-exposure has been associated with
atherosclerosis,
hypertension,
cerebrovascular diseases,
ischemic heart disease, and peripheral vascular disorders, whereas
Fluoride-exposure manifests cardiac irregularities and
low blood pressure (BP). Present study aims to study the combined effects of these toxicants on various cardio-respiratory variables in male rats. Single intravenous (i.v.) dose of
arsenic (1, 5, 10 mg/kg) or
fluoride (5, 10, 20, 36.5 mg/kg) either alone or in combination were administered. Individual exposure to
arsenic or
fluoride led to a significant depletion of mean arterial pressure, heart rate (HR), respiration rate and neuromuscular (NM) transmission in a dose-dependent manner. These changes were accompanied by increased levels of blood
reactive oxygen species (ROS) and decreased
glutathione (GSH) concentrations. An increase in the blood acetyl
cholinesterase (AChE) activity was observed in both
arsenic or
fluoride exposed rats. These changes were significantly more pronounced in
arsenic-exposed animals than in
fluoride. During combined exposure to
arsenic (5 mg/kg) +
fluoride (20 mg/kg) or
arsenic (10 mg/kg) +
fluoride (36.5 mg/kg) the toxic effects were more pronounced compared to individual toxicities of
arsenic or
fluoride alone. However, combined exposure to
arsenic (5 mg/kg) +
fluoride (36.5 mg/kg) resulted in antagonistic effects on variables suggestive of altered cardio-respiratory function and oxidative stress. The results from the present study suggest that
arsenic or
fluoride individually demonstrate cardio-
respiratory failure at all doses whereas during combination exposure these toxins show variable toxicities; both synergistic and antagonistic effects depending upon the dose. Moreover, it may be concluded that
arsenic and/or
fluoride cardio-respiratory toxicity may be mediated via oxidative stress. However, these results are new in the discipline thus requires further exploration.