ROS and its correlation with unexplained subfertility and Unexplained REc abortios

Problem & Solutions:--The etiologies of unexplained infertility and recurrent pregnancy loss has remained  unknown to many of us . This poses  a scientific challenge because even  a senior clinician can’t focus on any definite etiology in a given case.  But many basic scientists uphold the view that  at least in some of such so called UNEXPLAINED cases “Reactive Oxygen Species” ,  Oxidative Stress may play a big role in spoiling the game.

Q.1; Back to basics-What is known to us? :-We know that the  most stable form of an atom is its ground state where each outermost shell electron is paired with a complimentary electron. These electron pairs spin in opposite directions creating a balanced atom.

Q.2:-What are Free radicals ? Ans: These are  independent atomic species with unpaired outer shell electrons. As covalent bonds are broken between molecules, lone pair electrons accompany each separated atom.

 Q. 3: What are ROS ?? Ans:- Free radicals with oxygen centers are commonly known as reactive oxygen species (ROS). ROS have two unpaired electrons that are located in the outer shell of the atom. To achieve a ground state, free radicals commonly steal electrons from neigh- boring molecules. The stealing of a single electron results in the formation of a free radical containing one final unpaired  electron. Consequently, electrons spinning antiparallel to this final unpaired electron are stolen from a bystander molecule which returns the unstable atom to its preferred ground state. An oxidant-antioxidant balance exists in vivo.

Q.4:-Where Free radicals are commonly seen ? Which parts of body are common sites??  Ans:-Oxygen species are most commonly formed during the A) inner mitochondrial membrane’s electron transport chain, specifically via the intermediate reduction states of complex I and complex III. Unlike other oxidants (e.g., molecular oxygen) ROS are unstable and aggressive molecules that are not capable of diffusing across biological membranes due to their polar nature

B) Mitochondrial energy production is impeded :--We know that the electron transport chain (one carbon metabolism)  utilizes oxygen to produce adenosine triphosphate (ATP), energy that a cell exploits to sustain its metabolic activity.

C)  DNA damage and  increases cell apoptosis, Finally death of cells.

Q.5:- What are the ill effects of ROS?? Ans:-Reactive oxygen species function as either oxidants or reducers in response to their changing molecular environments. They also act distinctly when present in diverse tissue concentrations. For example, the presence of ROS in tissue at moderate levels indicates their function as normal cell signal responders. But once ROS are present in high concentrations, it is probable that their overabundance is a product of oxidative damage which triggers DNA damage and  increases cell apoptosis, also referred to as cellular death.

Q. 6:  How to Classify the types of ROS? Ans:-. A number of ROS are commonly generated in the female reproductive tract including the 1) hydroxyl radical (OH-), 2) hydrogen peroxide (H2O2), and 3) the superoxide anion radical (O2-). The superoxide anion radical is a primary ROS of medium reactivity . It is produced when an oxygen molecule gains one electron, consequently allowing the unstable atom to maintain an additional unpaired outer shell electron.

Q.7: What are secondary ROS?? Ans:  When ROS is present at high concentrations, then free O2 - supports cell component modifications and is susceptible to producing secondary ROS through metal-catalyzed or enzyme-catalyzed processes. The superoxide anion itself converts to H2O2--a com- pound easily catalyzed by the enzyme superoxide dismutase (SOD) in the production of supplementary secondary ROS.

Universal chain reactions lead to the generation of the mitochondrial superoxide anion in vivo. This radical’s rate of formation depends on oxygen flow through the mitochondria. Hydrogen peroxide is produced readily in vivo by assorted reactions as well. The hydrogen peroxide radical conversion is catalyzed by glutathione peroxidase during the alteration of glutathione to oxidized glutathione, converting H2O2 to H2O. Hydrogen peroxide may also be converted to the hydroxyl radical via the Harber-Weiss reaction.

Q. 8: Which one is the most powerful free radical?? The Convid -9 ?  Ans:-Hydroxyl radicals are the most powerful free radicals due to their simultaneous short life spans and damaging properties.

Hydroxyl radicals cause DNA damage by breaking nucleic acid strands via the modification of pyrimidines and purines.