Antioxidants

Antioxidants are naturally occurring or synthetic biomolecules that prevent free radical-induced damage by averting the formation of radicals, scavenging them, or promoting their decomposition in the body. Their neutralizing capabilities reside in their ability to donate an electron to ward off the deleterious effects of the highly reactive radicals or by converting ROS into different, less harmful molecules.

There are three main routes of defense antioxidants utilized in combating detrimental ROS levels: prevention, interception, and repair. The seminal plasma transition metals are capable of preventing ROS from initiating chain reaction. These chelating metals are vital in controlling LPO damage to sperm. However, as these chelators become loosely bound to reduced oxygen products, they can generate secondary or even more reactive oxidants.

Certain antioxidants can intercept and impede free radical-induced chain reactions, forming nonradical end products. a-Tocopherol is a form of vitamin E antioxidant with chain-breaking/intercepting abilities [41] . It is capable of inhibiting LPO in membranes by scavenging ROS, such as the peroxyl and alkoxyl radicals. However, this system is highly regulated and a-tocopherol's ability to maintain a steady rate of radical reduction in the plasma membrane is dependent on its recycling by external reducing agents. Therefore, a-tocopherol is able to function even at low concentrations.

The last mechanistic process of defense employed by antioxidants is to simply repair any damage caused. In cases of minimal oxidative damage, normal physiological function may be restored. However, if OS-induced damage subsists, spermatozoa are incapable of repairing this level of injury. This is often due to the lack of an intricate cytoplasmic enzyme/antioxidant system in mature sperm that is required to treat this type of damage, which demonstrates the high susceptibility of spermatozoa to oxidative insults [42].

Antioxidants come in a variety of forms, ranging from those generated endog-enously by the body to those acquired exogenously through the consumption of certain foods or dietary supplements. When the natural balance between oxidants and antioxidants within the body is perturbed via antioxidant deficiency or overwhelming ROS production, the subsequent adverse effects have been found to be diminished, and sometimes resolved, through bodily antioxidant defense and supplementation [43]. Since human spermatozoa membranes are rich in unsaturated fatty acids, they are sensitive to oxygen-induced damage mediated by LPO.

Normally, the seminal plasma is well endowed with an array of antioxidant defense mechanisms to quench ROS and protect against any possible damage to spermatozoa. The variety of pathways compensate for the deficiency in cytoplasmic enzymes in sperm. Potential anti-ROS enzymes and other low molecular weight nonenzymatic substances make up the total antioxidant capacity (TAC) of the seminal plasma. Fertile men were reported to have a higher, more effective TAC in comparison to infertile male subjects [44] . If the male reproductive system becomes compromised by infection or any impairment in spermatogenesis that elevates ROS levels, antioxidant defense mechanisms may be overwhelmed and depleted, and thus result in OS. Given that various studies implicate OS in poor sperm samples, medical treatments that reduce or protect against OS may be an appropriate strategy to alleviate infertility in men with iOAT.

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100 Pregnancy Tips

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