| Our hair frames our face. Hair is one of our few physical characteristics we can voluntarily control, through hair length, style, and color. Our hairstyle is often a nonverbal expression of our personality. Androgenetic alopecia (AGA) affects 50% of men by 50 years of age and nearly 50% of women. The slow, relentless, involuntary loss of hair creates emotional stress for millions of men and women. With the improvement of living standards, people increasingly demands diagnosis and treatment of hair loss, modern medicine also increasing emphasis on the study of hair loss. Although, there are safe, effective medications, oral drugs of Finasteride and topical external drugs of Minoxidil, available to treat AGA, which merely slow or prevent hair loss and do not promote re-growth of hair, and hair loss will continue after the stopping the above drugs. In 1959, Orentreich first established the concept of'donor dominance'through clinical trials, hair transplantation has become the most direct and effective treatment to various hair loss. The past decade has seen significant developments in the management of alopecia.In 1984, Headington demonstrated that hairs did not occur singly, but as naturally occurring groups that were referred to as the follicular unit. Each unit consisted of 1 to 4 terminal follicles; associated sebaceous lobules and insertions of the arrectores pili; perifollicular vascular plexus and neural net; and perifollicular collagen. But the following years, the clinician has not been pay more attention to follicular unit transplantation. In 1990s, for the'Rolls Royce of hair transplantation' follicular unit transplantation (FUT), which has now become the gold standard for hair transplantation. Dissection of follicular unit (FU) is the most important steps in follicular unit transplantation. The single strip which dissected from occipital is first dissected into small slivers of 1 or 2 follicular unit width (1-2 mm) under a stereomicroscope. The slivers are then dissected into 1-4 hair follicular unit either under a magnifying loupe or a microscope, or directly pull out follicular unit. Lastly, follicular unit, in a smooth manner, are inserted into the recipient site by other instruments. The grafted hairs may start falling at 2 weeks due to postoperative telogen effluvium. The hairs start growing by 3-4 months at the rate of one cm every month, with full cosmetic results at the sixth month. Sometimes, It is need 2-3 times surgery to get a better aesthetic appearance. In recent years, the technology is widely used in hair, eyebrows, beard, and even pubic hair restoration, because it can shape a more natural appearance.Although follicular unit transplantation has now become the gold standard of hair transplantation, new problems arouse with this technique due to the increased fragility of the follicular unit as compared to larger minimicrografts. Many scholars at home and abroad have done more study on which factors can affect the survival rate after follicular unit transplantation during the hair transplant process But they do not form a consistent view on follicular unit transplantation specific survival rates and the density of the first transplantation in various hospitals and research units. Many factors can affect the survival rates of follicular unit. In 1997, Greco concluded that a human factor (H-factor) could be responsible for poor hair growth. Gandelman concluded that no alterations were detected in follicular unit which had been crushed, bent, or stretched. In his trial, there were two disadvantages:he did not specific describe the size of follicular unit; and in addition, the sample is two small. Seager proposed that follicular unit leaving more protective tissue around them can results in a higher hair yield by comparing the test. Similar study also identified by Michael, but their conclusion of the study is still controversial. At the same time, they do not give a quantitative standard about the size of hair follicle graft.1. The trimming size of hair follicle grafts not only affect their survival rate but also closely related to the density of hair transplantation after restoration. Thought related studies said they should reserve some surrounding tissue such as dermal and sebaceous glands, there is not a quantitative standard about the size of hair follicle grafts. Particularly, for China, there are not study on the relationship between the size of follicular unit and its survival rate.2. In the process of follicular unit transplantation, there is not a quantitative standard about the impact of extrusion of surgical instruments on graft survival rates.Our experiment is to imitate the clinical follicular unit transplantation, to observe the effects of different treatment on graft survival rate, including trimming the different sizes of follicular unit, crushing the different parts of follicular unit with surgical specific instruments. Specific data acquired from experiments can not only provide a relative quantitative criterion for clinical hair transplantation, but also improve transplant survival rates, increase graft density, faster transfer speed, reduce the difficulty of transplantation, facilitate small and medium-sized hospital in the popularization and application of hair transplant technology 1. Firstly, human hair follicles were isolated by microdissection. Secondly, 1-hair of follicular unit were divided A, B and C groups based on thickness of retained protective tissue around the outer root sheath. Thirdly, three groups treated with HE staining to detect the histological changes of cells and organ cultured for 6 days to observe the morphological changes and elongation of follicular unit.2. Human Follicular units were isolated by microdissection under a stereo dissecting microscope. Then,1-hair of anagen follicular unit were randomly divided into A, B and C groups, A and B groups submitted to controlled injury with microsurgery imposed to the dermal papilla and the bulge of follicular unit, respectively, C was control group without any treatment. Thirdly, three groups treated with HE staining to detect the histological changes of cells and organ cultured for 6 days to observe the morphological changes and elongation of follicular unit.1. The source and the preparation of specimens. Occipital scalp skin was obtained form healthy patients at plastic surgery of hair transplantation. Isolation of anagen hair follicles was achieved by using a surgical blads, microscissors, and watchmakers forceps under a stereo dissecting microscope(×10 to×20) and was preserved in sterile Petri dishes containing 0℃saline. As in micrograft preparation for hair transplantation procedures, each follicle was isolated intact as a whole, always maintaining a significant amount of tissue (epidermis, dermis, subcutaneous fat) around the entire length of the follicle.2. Experimental group We choice 1-hair of follicular unit form specimens and were divided A, B and C groups based on thickness of retained protective tissue around the outer root sheath,0.3mm is a standard unit. Based on the first part,1-hair of anagen follicular unit were randomly divided into A, B and C groups, A and B groups submitted to controlled injury with microsurgery imposed to the dermal papilla and the bulge of follicular unit, respectively, C was control group without any treatment.3. Detection intex follicular unit were used for organ culture. Methods of organ culture were described elsewhere. Every day follicular unit was observed to detect the morphological changes of hair follicles with Inverted microscope. Three groups treated with HE staining to detect the histological changes of cells and organ cultured for 6 days to observe the morphological changes and elongation of follicular unit.The final data are represented by x±S. The significance test of mean between multiple groups was used the One-way ANOVA and LSD-t ways by the statistical analysis software which was SPSS 13.0. But we used the Welch's approximate ANOVA and Dunnett's T3 to test the datas when the equal variances were not assumed. We usedχ2 test to test the datas in R-C tables. The a's value is equal to 0.05 in all statistical analysis proceedings.1. There is not significant morphologic change among hair follicles after organ culture for 6 days. Hair growth rate of hair follicle after a 6-day organ culture period is 81.5%,91.7%,92.6%, respectively. The mean hair elongation of hair follicle after a 6-day organ culture period is (1.24±0.10), (1.36±0.10), (1.36±0.12) mm, respectively. There are significant difference between A and B, and, A and C, (P< 0.05 and P<0.05).2. There is not significant morphologic change among hair follicles after organ culture for 6 days. Hair growth rate of hair follicle after a 6-day organ culture period is 75.6%,90.0%,92.2%, respectively. The mean hair elongation of hair follicle after a 6-day organ culture period is (1.11±0.11), (1.26±0.09), (1.29±0.10)mm, respectively. There are significant difference between A and B, and, A and C, (P< 0.05 and P<0.05).1. Our trial confirms that there are no significant difference among three groups of hair follicles after 6-day organ culture, but there are significant difference between A and B, and, A and C, meanwhile, A group was lower than B, C group. Hair follicles were fully exposed will affect its activity, the growth rate of hair follicle will be significantly reduced. Although we do not know whether the conclusions of this study are still relevant in the body, for vitro experiments, the hair follicle outer root sheath which is left 0.3 mm thickness of protection organization can ensure its survival rate. Because the thickness of 0.3 mm is very thin, hair follicles are not suitable to separate under naked eyes.2. In the process of hair transplantation, we have to be careful operation, in particular, should not to rudely clamp dermal papilla. The damage to dermal papilla will affect the hair growth. This experiment was carried out in vitro. For in vivo, since the hair will go through a shedding period and then re-grow hair shaft after transplantation, whether the conclusions are applicable to the body is not sure, so we have to be further explored.
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