Evaluation of the antioxidant effects of melatonin on the larynx mucosa of rats exposed to environmental tobacco smoke

Melatonin as a powerful antioxidant

Melatonin is a hormone that has many body functions and, for several decades, its antioxidant potential has been increasingly talked about. There is a relationship between failure in melatonin production in the pineal gland, an insufficient supply of this hormone to the body, and the occurrence of free radical etiology diseases such as neurodegenerative diseases, cardiovascular diseases, diabetes, cancer and others. Despite the development of molecular biology, numerous in vitro and in vivo studies, the exact mechanism of melatonin antioxidant activity is still unknown. Nowadays, the use of melatonin supplementation is more and more common, not only to prevent insomnia, but also to slow down the aging process and provide protection against diseases. The aim of this study is to get acquainted with current reports on melatonin, antioxidative mechanisms and their importance in diseases of free radical etiology.

Protective effect of aerobic exercise on the vocal folds against cigarette smoke exposure

PURPOSE

Laryngeal pathologies due to cigarette smoking vary among individuals, whereas some smokers remain disease free. These differences can be explained by multiple factors among individuals. In this context, an animal study was designed to determine if there is any protective effect of aerobic exercise against the detrimental effects of cigarette smoke on laryngeal tissues.

METHODS

A total of 24 male Wistar albino rats were divided into three groups of eight animals each: control (no smoke exposure), smoking (smoke exposure), and exercise (smoke exposure and exercise) groups. Histopathological (light and electron microscopy) and immunohistochemical (GSTA1, CYP1A1, CYP2E1) evaluations of the vocal folds were performed at the end of experimental period.

RESULTS

Exercise group revealed statistically significant decrease in edema (p = 0.03) and inflammatory cell infiltration (p = 0.02) compared to smoking group. In electron microscopic evaluation; cytoplasmic vacuoles were also present in exercise group, but were smaller than smoking group. Edema and swollen mitochondria were also less prominent in exercise group. Condensed chromatin material in the periphery of nucleus was observed only in few cells in exercise group, and observed in more cells in smoking group. GSTA1 expression was higher (p = 0.047) and CYP1A1 expression was lower (p = 0.01) in exercise group than smoking group.

CONCLUSIONS

Our results indicate that aerobic exercise has a protective role on the larynx against the damaging effect of cigarette smoke. Smokers who exercise regularly may be at a lower risk of cigarette smoke-related laryngeal diseases, as compared with those who do not exercise.

Protecting the BBB endothelium against cigarette smoke-induced oxidative stress using popular antioxidants: Are they really beneficial?

Blood Brain Barrier (BBB) exposed to realistic concentrations (comparable to a chronic heavy smoker) of Cigarette Smoke Extract (CSE) triggers a strong endothelial inflammatory response which can lead to the onset of neurological disorders. The involvement of Reactive Oxygen Species (ROS) in this inflammatory cascade is evident from the up-regulation of nuclear factor erythroid 2 related factor 2 (Nrf-2), a transcription factor involved in anti-oxidant response signaling in CSE exposed endothelial cells. We have shown that pre-treatment with α-tocopherol and/or ascorbic acid is highly protective for the BBB, thus suggesting that, prophylactic administration of antioxidants can reduce CSE and/or inflammatory-dependent BBB damage. We have assessed and ranked the protective effects of 5 popular OTC antioxidants (Coenzyme Q10, melatonin, glutathione, lipoic acid and resveratrol) against CSE-induced BBB endothelial damage using hCMEC/D3 cells. The analysis of pro-inflammatory cytokines release by ELISA revealed that resveratrol, lipoic acid melatonin and Co-Q10 inhibited the BBB endothelial release of pro-inflammatory cytokines IL-6 and IL-8, reduced (not Co-Q10) CSE-induced up-regulation of Platelet Cell Adhesion Molecule-1 (PECAM-1), Vascular Cell Adhesion Molecule-1 (VCAM-1) & E-selectin and inhibited monocytes-endothelial cell adhesion. The anti-inflammatory effects correlated with the anti-oxidative protection endowed by these compounds as evidenced by upregulation of NADPH: Quinone Oxidoreductase 1 (NQO1) and reduced cellular oxidative stress. CSE-induced release of Vascular Endothelial Growth Factor (VEGF) was inhibited by all tested compounds although the effect was not strictly dose-dependent. Further in vivo studies are required to validate our results and expand our current study to include combinatorial treatments.