Evaluation of the cardiovascular effects of varenicline in rats

Abstract

BackgroundCardiovascular disease is an important cause of morbidity and mortality among tobacco users. Varenicline is widely used worldwide to help smoking cessation, but some published studies have reported associated cardiovascular events.ObjectiveTo determine the cardiovascular toxicity induced by varenicline in rats.Materials and methodsWe randomly separated 34 rats into two groups: 1) the control group (given only distilled water orally, n=10) and the varenicline group (given 9 μg/kg/day varenicline on days 1–3, 9 μg/kg twice daily on days 4–7, and 18 μg/kg twice daily on days 8–90 [total 83 days], n=24). Each group was then subdivided equally into acute and chronic subgroups, and all rats in these groups were euthanized with anesthesia overdose on days 45 and 90, respectively. Body and heart weights, hemodynamic (mean oxygen saturation, mean blood pressure, and heart rate, electrocardiographic (PR, QRS, and QT intervals) biochemical (oxidants and antioxidants), and histopathological analyses (including immunostaining) were performed.ResultsAcute varenicline exposure resulted in loss of body weight, while chronic varenicline exposure caused heart weight loss and decreased mean blood pressure, induced lipid peroxidation, and reduced antioxidant activity. Both acute and chronic varenicline exposure caused impairment of mean oxygen saturation. QT interval was prolonged in the chronic varenicline group, while PR interval prolongation was statistically significant in both the control and acute varenicline groups. Caspase-9 activity was also significantly increased by chronic exposure. Moreover, histopathological observations revealed severe morphological heart damage in both groups.ConclusionAdverse effects of chronic varenicline exposure on cardiovascular tissue were confirmed by our electrocardiographic, biochemical, and histopathological analyses. This issue needs to be investigated with new experimental and clinical studies to evaluate the exact mechanism(s) of the detrimental effects of varenicline. Physicians should bear in mind the toxic effects of varenicline on the cardiovascular system when prescribing it for smoking cessation.

Melatonin provides protection against heat stroke-induced myocardial injury in male rats

“…Pathological and morphological changes were observed under a Karl Zeiss microscope (Göttingen, Germany). The severity of myocardial damage was semiquantitatively scored as 0 point (normal), 0.5 points (minor, 1.0 point (mild), 2.0 points (moderate) and 3.0 points (severe) …”

Disease-modifying antirheumatic drugs and remote ischemic postconditioning ameliorate the myocardial injury in rats under cerebral stroke

“…An overall score of cardiac damage severity was semiquantitively assessed regarding apoptosis, necrosis, isolated lymphocyte increase, ovoid nucleus loss, congestion, vascular proliferation, and edema. The severity of myocardial damage was semiquantitatively scored as 0 (normal), 1.0 (mild), 2.0 (moderate), and 3.0 (severe) as previously described by Selcuk et al (10).…”

“…The severity of myocardial damage was semiquantitatively scored as 0 (normal), 1.0 (mild), 2.0 (moderate), and 3.0 (severe) as previously described by Selcuk et al (10).…”

“…Previous studies have shown that ischemic postconditioning reduces the size of the infarct by preventing the formation of free radicals and slowing apoptosis (9). Cardiac ischemia includes myxoid changes in the myocardium, such as neutrophil/leukocyte infiltrations among muscle fibers, necrosis, and subsequent fibrosis (10).…”

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“…14) that typifies the elastic lamina found in human and animal blood vessels. The study of aortic microstructure and age-related changes is an urgent area of medical research (Novotny et al, 2017;Tonar et al, 2015;Akhtar et al, 2011;Selçuk et al, 2015).…”