Wednesday, September 25, 2019

Molecular basis of aging in relation to fertility Essay

Molecular basis of aging in relation to fertility - Essay Example Aging is defined as â€Å"a progressive, time-dependent deterioration of an organism’s capacity to respond to environmental changes, which ultimately makes it susceptible to death† (Allen and Balin 4). It is a widely-accepted idea that aging is a natural process that occurs in all living organisms. Since the process of aging most likely would be affecting an organism’s overall body functions, it would also greatly affect its capacity to reproduce, eventually leading to a decrease or the loss of fertility of the said organism (Liu and Case 1169). At present, there are numerous links between chromosomal and DNA damage not just to the aging process of an organism but also on fertility. A female’s capacity to conceive and give birth, or a male’s capability to contribute in conceiving a child is called fertility (Masoro 161). In order to proliferate the species well into numerous and succeeding generations, organisms must be able to produce as much offsp ring as possible that are able to adapt to the current environment that they live on. For that to happen, the process called natural selection takes place (Torday and Rehan 12). Also, the energy that flows within the organism is appropriated in such a way that during the process of reproduction, most of the energy from the consumption of food is distributed to the body’s reproductive systems, mostly to the rapidly-dividing cells called the gametes. However, once the organism starts the process of aging, the energy being exerted for reproduction is reduced and more focus is given to the maintenance of the organism’s body, especially when there is the presence of a rapid breakdown of cells as well as the decline of cell-to-cell communication within the systems and organs (13). Not only is the production of cells affected by aging, but also the process of DNA replication and repair as well. Due to the proliferation of damaged DNA especially in the sex cells of the organis m, it would eventually contribute to the creation of deformed or dysfunctional oocytes or spermatozoa that would eventually be the cause of the loss of reproductive capability or infertility among aging organisms (Sikka 78). Among pregnant women, the imbalance of antioxidants and pro-oxidants may result to oxidative stress due to reactive oxygen species (ROS), which could affect DNA production when in excess, or affect cell-signaling pathways when deficient (Dupont, Cordier and Junien 25). Also, due to the age-associated decline of female fertility can be attributed to the abnormalities found in the oocytes themselves. Due to the abnormalities in the folding of the DNA and eventually, the abnormalities in the alignment of the chromosomes during meiosis and diakinesis which can be attributed to the mutations in the microtubules, preimplantation of embryos or aneuploidy in the fertilized egg may cause spontaneous abortions among older pregnant females (The Practice Committee of the Am erican Society for Reproductive Medicine (PCASRM) 248). Male fertility is also greatly affected by ROS, wherein the spermatozoa membranes would be highly-susceptible to oxygen damage due to the peroxidation of lipid membranes, damaging the sperm and rendering them incapable of fertilizing the ovum (Sikka 78). Also, the presence of errors in the DNA called nicks could also contribute to male infertility due to loosely-packed DNA and chromatin disorganization (Sakkas, Urner and Bizzaro 11). These nicks may be attributed to age-induced DNA

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