The proliferative activity of the follicular cells, which influences hair shaft production, could be assessed by applying immunohistochemical methods for visualizing the cell cycle
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Figure 9.5 Detection of apoptosis in the hair follicle melanocytes after laser treatment by simultaneous visualization of pMel-17 (Rhodamine) and TUNEL staining (FITC). A—in anagen hair follicle, pMel-17 immunofluorescence (Rhodamine) was detected in the hair matrix (arrow) and no TUNEL positive cells were detected; B—immediately after treatment with 5 J/cm2 laser, appearance of apoptotic TUNEL positive melanocytes expressing pMel-17 protein were seen in hair follicle melanogenic area above the dermal papilla (arrow), and TUNEL positive cells were detected in the differentiating keratinocytes of the hair shaft containing melanin granules (asterisk); C— in hair follicles exposed to 10 J/cm2 laser, the number of TUNEL-positive cells in the hair matrix and the hair shaft increased (arrow and asterisk, respectively), and appeared in the dermal papilla. |
associated antigens. One such antigen that is broadly used for the detection of proliferating cells is Ki-67. The monoclonal antibody against Ki-67 can be used to recognize a proliferation specific antigen expressed in the nuclei during the G1, S, G2, and M phase of growth, but not in the G0 phase [81]. In the hair follicle, Ki-67 immunoreactivity is usually seen in cells of the hair bulb and in distinct cell population of the outer root sheath of the anagen hair follicle, while it is progressively decreased with development of catagen phase. Quantitative analysis of Ki-67 in the hair follicles in response to different laser treatments could provide information on status of proliferative activity of follicular cells, which reflects the ability of the hair follicle to produce the hair shaft.