| The regulation and structure of hair follicle are | | | | study the regulatory events in hair follicle |
| rather complex - they are composed of more | | | | development and hair growth. These studies are |
| than 20 cells and involve numerous signaling | | | | directly relevant to hair follicle biology in humans. |
| events. These complexities make the | | | | Rodent models are especially valued in many |
| experimental hair research a challenging task. The | | | | researches due to a number of reasons, such as |
| scientists proceed with utmost care in choosing | | | | 1. their ready availability, |
| the experimental model for finding the answer to | | | | 2. rapid breeding, |
| each question related to hair growth or diseases. | | | | 3. known genetics in inbred strains, |
| Analysis in Humans | | | | 4. the ability to modify their genetic profile, |
| The task of monitoring hair growth and hair | | | | 5. the ability to control environmental input, and |
| abnormalities apparently appears to be easy due | | | | 6. the ability to conduct invasive procedures. |
| to their localization on the skin surface. Then you | | | | Transplant models |
| can easily access the hair fibers and hair roots for | | | | Tissue transplant models open up new possibilities; |
| non-invasive collection. Then, the hair cycling | | | | this approach involves the transplantation of |
| anomalies can also be easily evaluated in clinical | | | | diseased hair-bearing human skin onto |
| diagnostics, using simple light microscopy. | | | | immunodeficient mice. This approach is helpful in |
| Phototrichograms, and the recent development of | | | | the study and manipulation of human hair growth. |
| the "trichoscan(TM)" technique, allow quantification | | | | This method has been applied in research on |
| of hair growth in vivo. Moreover, the use of global | | | | androgenetic alopecia where no satisfactory |
| photography techniques has emerged as the | | | | rodent model was available, alopecia areata, and |
| most popular approach in treatment evaluation. It | | | | for the study of several forms of genetic |
| is true that these approaches prove to be | | | | trichoses. This method was also proved to be |
| effective in the diagnosis of disease and clinical | | | | helpful in understanding basic hair biology. The |
| treatment trials; but they provide only limited | | | | advantage of this approach particularly relates to |
| information about the hair follicle in the skin. More | | | | the evaluation of drugs and their impact on hair |
| invasive techniques are needed to characterise | | | | growth. However, the approach has its limitations |
| hair follicles. So far the clinics use techniques such | | | | too. |
| as tissue biopsy and histological analysis of the hair | | | | Cell culture |
| follicle structure. | | | | Culture techniques provide another useful tool for |
| Animal models | | | | functional research. Hair follicles are composed of |
| Using animal models in the experimentations | | | | populations of interacting cells that can be readily |
| relating to hair follicle development and hair | | | | identified and are clustered in discrete sites. This |
| diseases have become more popular in recent | | | | allows the isolation of different cell types to |
| decades. Developmental biology is increasingly | | | | observe pronounced interactive abilities when |
| making use of model organisms such as | | | | cultured in vitro. Primary cell cultures from mouse |
| Drosophila, Xenopus and Zebrafish. These have | | | | and human hair follicles, including hair follicle |
| provided valuable insights into the role of | | | | keratinocytes, dermal papilla cells and |
| conserved signalling pathways including Hedgehog | | | | melanocytes, provide important information on |
| or Wingless in pattern formation and formation of | | | | the expression of mediators and the behaviour of |
| skin appendages in general. Genetically engineered | | | | single cell populations. |
| mice are being used as mammalian models, to | | | | |