Microwaves from mobile phones are one of the environmental toxicants that are capable of compromising male fertility by inducing oxidative stress and apoptosis in the testes. Melatonin is a lipophilic tryptophan indole amine and a potent antioxidant. The aim of the study was to evaluate the effect of melatonin treatment on oxidative stress parameters and DNA fragmentation in the testicular tissue of rats exposed to microwave radiation (4 h/day). Adult Wistar rats were divided in 4 groups: I--treated with saline; II--treated with melatonin; III--exposed to microwaves; IV--exposed to microwaves and treated with melatonin. The melatonin (2 mg/kg ip) was administered daily. The animals were sacrificed after 20, 40 and 60 days. Melatonin treatment prevented previously registered increases in malondialdehyde after only 20 days. Furthermore, it reversed the effects of microwave exposure on xanthine oxidase (after 40 days) and acid-DNase activity (after 20 days). However, neither protein carbonyl content nor catalase and alkaline Dnase activity were changed due to melatonin treatment. Melatonin exerts potent antioxidant effects in the testes of rats exposed to microwaves by decreasing the intensity of oxidative stress; it also reduces DNA fragmentation.

Coronavirus disease 2019 (COVID-19) is an acute respiratory disease associated with severe systemic inflammation. The optimal status of vitamins and microelements is considered crucial for the proper functioning of the immune system and necessary for successful recovery. Most patients with respiratory distress in COVID-19 are vitamin and microelement deficient, with vitamin D and Se deficiency being the most common. Anyway, various micronutrient supplements are widely and arbitrarily used for prevention or in the treatment of COVID-19. We aimed to summarise current knowledge about molecular and physiological mechanisms of vitamins (D, A, C, B₆, B₉and B₁₂) and microelements (Se, Zn, Cu and Fe) involved in the immune system regulation in consideration with COVID-19 pathogenesis, as well as recent findings related to their usage and effects in the prevention and treatment of COVID-19. In the early course of the pandemic, several, mainly observational, studies reported an association of some micronutrients, such as vitamin C, D and Zn, with severity reduction and survival improvement. Still, emerging randomised controlled trials showed no effect of vitamin D on hospitalisation length and no effect of vitamin C and Zn on symptom reduction. Up to date, there is evidence neither for nor against the use of micronutrients in the treatment of COVID-19. The doses that exceed the recommended for the general population and age group should not be used, except in clinical trials. Benefits of supplementation are primarily expected in populations prone to micronutrient deficiencies, who are, as well, at a higher risk of worse outcomes in COVID-19.

The mechanisms through which melatonin exerts its inhibitory effect on cell death remains insufficiently clarified. The subject of the present study is the evaluation of the hepatoprotective effects of melatonin on the inhibition of apoptotic and oxidative processes and activation of survival pathways, in comparison with betaine, in a primary culture of hepatocytes that have undergone Fas-ligand apoptosis. Melatonin exerted a protective effect on membrane bilayer stability through the inhibition of phosphatidylserine externalization, Bax expression and xanthine oxidase catalyzed free-radical liberation. It also reduced liberation of cellular and membrane-bound enzymes and endonuclease catalyzed DNA fragmentation. Betaine hydrochloride did not exert these effects, when administered alone or co-incubated with anti-Fas antibodies. The in silico Molinspiration tool, which was employed to calculate melatonin and betaine physico-chemical properties and membrane interaction indicated that melatonin may easily cross and interact with biological membranes and maintain membrane phospholipid structural topography. It was documented to occur via non-receptor mechanisms in more than 75%; this may clarify melatonin as suitable for nanoliposome-based delivery, where it was also able to successfully counteract induced oxidative stress. This could not be considered for betaine hydrochloride. The use of lipophilic compounds like melatonin, encapsulated in nanoliposomes, could therefore be a preferable tool in the successful membrane-preservation therapy of liver apoptosis, rather than the use of hydrophilic compounds, like betaine hydrochloride.

Melatonin protects rat thymus against oxidative stress caused by exposure to microwaves and modulates proliferation/apoptosis of thymocytes