� � Jun-23-2009
In a major breakthrough, Japanese researchers have discovered that trauma causing damage to DNA is primarily responsible for grey hair. The findings of a recent study undertaken by scientists from different universities in Japan involving mice has revealed that stress, specially the type that harms DNA, is liable for the attractive brown fur of an aging mouse turning grey.
During the course of their experimentation on mice, Emi Nishimura of the Tokyo Medical and Dental University, Ken Inomata of Kanazawa University and their associates cut into pieces the ostensible means that leads to the discoloration of the hair through the aging process. In the course of their study, the researchers made the mice undergo a very high degree of a kind of stress known as 'genotoxic stress' that results in the injury of DNA. The type of stress applied on the mice may be described as something similar to what all living beings regularly endure because of coming into contact with ultraviolet rays, several additional emissions as well as some specific sorts of chemicals.
According to Emi Nishimura of the Tokyo Medical and Dental University, it has been approximated that a solitary cell in mammals are able to endure around 100,000 occurrences that dent DNA during the course of a single day! Normally, the cells possess the mechanism to repair the damages done to them on their own, but severe injuries to cells owing to extreme pressure or stress are often permanent and cannot be overturned.
It is worth mentioning here that during the trials, the researchers caused the mice to undergo profound stress by subjecting the mice to X-rays and/ or impregnating them with chemicals like hydrogen peroxide that damage DNA. Having put the mice under tremendous stress, the scientists meticulously examined the transformations in their cells. Hair spores possess stem cells that comparatively do not have any special functions, but when mature, they are capable of becoming specialized cells. The stem cells in the hair create cells that produce pigments and are known as melanocytes. Although the stem cells reproduce from time to time, the melanocytes never reproduce and ultimately expire.
During the course of the experiments, the scientists discovered that once the stem cells in the hair are damaged on being subjected to 'genotoxic stress', instead of continuing to be stem cells, they transform into full-grown melanocyte cells. Nevertheless, it was also found that these damaged cells stay put in the regions where the stem cells are normally found. In other words, after enduring the 'genotoxic stress' these mature melanocytes are not found in areas where the melanocytes normally develop. In fact, during earlier studies undertaken on the topic, scientists were bewildered to note that while a living being aged, these mature melanocytes were found in the 'wrong' areas.
Since the melanocytes never reproduce and expire after a brief existence, it generally leads to a diminishing population of stem cells causing the hair to turn grey provided an excessive of stem cells transform into mature melanocytes. Nevertheless, the investigators have put forward the theory that transformation of harmed stem cells into melanocytes may perhaps be necessary to ascertain that the population of the stem cells remains healthy on the whole and also to thwart the perils of cancer.
During the course of their research, the scientists also discovered that the usual adaptation of a defective gene engaged in untimely aging conditions is able to safeguard the stem cells from maturing into adult pigment or color cells. The findings of this study back the theory that the damage to the long-lasting stem cells may perhaps be the reason behind the noticeable indications of aging.
Cells producing melanin as well as containing them are known as melanocytes. Melanin is a type of insoluble pigment present in almost all animals and is responsible for their skin's dark color. Melanin cells are present in all individuals and they have several functions in our body. It may be noted that the color of an individual's skin does not depend on the number of melanin cells he/ she has in their body, but the extent of their activeness. For instance, in the case of albinism, melanin cells are present in the body of the individual suffering from this condition, but their actions are restrained and, therefore, they are unable to produce pigment.
Besides being present in the skin, melanocytes are also found inside the brain, the heart, eyes as well as inside the ear, in addition to other different body parts. Usually, these cells lie buried under the exterior. Melanocyte cells make melanin acting in response to cues from the environment, which includes coming in contact with specific chemicals as well as ultraviolet (UV) radiation. Melanin produced by melanocytes goes out of these cells to the exterior of the tissue where the melanin cells are usually found. During the course of time, the melanin cells break down and require replacements with new melanin supplies from the basic melanocyte layer.
Disorders related to pigmentation or coloring, counting the inherited conditions and also those that are acquired, have the aptitude to influence the manner in which melanocytes function. In some cases these cells have a restrained activity which results in the formation of white or pale patches on different parts of the body, especially where the melanocyte cells do not produce any melanin. On the other hand, some melanocyte cells work overtime to produce excessive melanin and this leads to the color of the skin becoming dark. In fact, specific medicines also work in a similar fashion and this perhaps explains the reason as to why over a period of time, people who take certain prescription drugs develop dark skin.
Melanin found in the skin also possesses protective attributes. It soaks up ultraviolet (UV) radiation, thereby stopping it from moving to the nearby body tissues. Consequently, people who live in regions where they are exposed to the sun more frequently and also intensely usually have additional melanocyte cells in their body. These melanocyte cells work to make sure that there is a healthy layer of melanin cells in the bodies of these people so that they do not suffer from sunburns easily. In addition, a vigorous layer of melanin on their body also prevents any harm caused by the ultraviolet rays of the sun.
In addition to its protective properties, melanin also has several other roles in our body. For instance, it seems that melanin is the basis for a number of essential elements for some neurotransmitters in the brain. When the brain is in short supply of chemicals that it requires to carry out its functions, it requires synthesizing these chemical, especially in people who suffer from restricted production of melanin in the brain. It has been observed that such people endure decreased concentration of a number of neurotransmitters. In addition, people suffering from degenerative brain ailments may possibly also endure melanocyte destruction, thereby a decline in the functioning of melanin, which eventually results in decreased functioning of the brain. The part of the brain that is called the substantia nigra has been named so because it contains elevated melanin levels.